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- Ecology, driven from the Greek root oikos and logos, is the study of the interaction between the living organism and the environment.
- Ecology reveals the richness of the biosphere - the entire portion of the earth that's inhabited by life, and also helps with the understanding of the threats to the environment caused by human activities.
- Ecology and evolutionary biology are closely related in organic events that translate into effects over the longer scale of evolutionary time.
- The environment of any organism includes two components
- Abiotic, the nonliving components, such as chemical and physical factors like temperature, light, water, and nutrients.
- Biotic, the living organisms, or the biota.
- Ecology can be divided into areas of study ranging from the ecology of individual organisms to the dynamics of the ecosystems and landscapes.
- Organismal ecology, the study of how an organism's structure, physiology and behavior meet the challenges posed by the environment.
- Population ecology concentrates mainly on the factors that affect how many individuals of a particular species live in an area.
- Community ecology deals with the whole array of interacting species, such as predation, competition, and disease, affects a whole community.
- Landscape ecology focuses on the factors controlling the exchanges of energy, materials, and organisms among the ecosystem patches making up a landscape or a seascape.
- Biosphere is the global ecosystem --- the sum of all the planet's ecosystems.
- Interactions between organisms and the environment limit the distribution of species
- Biogeography is the study of the past and present distribution of individual species, in the context of evolutionary theory.
- Biogeography provides a good starting point for the understanding of what limits the geographic distribution of a species.
- Dispersal and Distribution
- Dispersal is the movement of individuals away from the centers of the high population density or from their area of origins.
- A successful transplant is not only that some of the dispersed organisms, but they must also survive and reproduce in the new area.
- If the species transplants are successful, then the potential range of the species is larger than its actual range.
- Behavior and Habitat Selection may limit dispersal and distribution even if the species are physically able to disperse into the unoccupied areas.
- Some insects only oviposit in response to a very narrow set of stimuli.
- Biotic factors that may limit distributions of a species
- Abiotic factors that may limit distributions of a species
- Temperature differences from one place to another
- Water availability differences
- Sunlight availability differences
- Degree of power of the wind
- Rocks and soils with difference in the pH value
- Temperature, water, sunlight, and wind are all the major compents of climate, the prevailing weather conditions in a particular area
- Macroclimate patterns on the global, regional, and local level
- Bodies of waters influences the climate along with the coasts of the continents by heating or cooling overlying air masses.
- Mountains have a significant effect on the amount of sunlight reaching an area, as well as on local temperature and rainfall.
- In addition to the global changes in day length, solar radiation, and temperature described earlier, the changing angle of the sun over the course of the year affects local environments.
- Microclimate patterns on those encountered by the community of organism, such as under a fallen log.
- Long-Term Climate Change
- Global climate change currently under way will profoundly affect the biosphere.
- Abiotic and biotic factors influence the structure and dynamics of aquatic biomes.
- Biomes are major types of ecological associations that occupy broad geographic regions of land or water.
- Aquatic biomes are distinguished by the ecologist into three zones
- Photic zone, where there is sufficient light for photosynthesis
- Aphotic zone, where little light penetrates.
- Benthic zone, made up of sand and organic and inorganic sediments.
- Benthic zone is occupied by communites of organisms collectively called benthos, which feed on detritus, a kind of dead organic matter which rains down from the productive surface waters of the photic zone.
- Major aquatic biomes
- Lakes are standing bodies of water covering thousands of square kilometers
- A wetland is an area covered with water for a long enough period to support aquatic plants
- The most prominent physical characteristic of streams and rivers is current
- Headwater streams are generally cold, clear, turbulent, and swift
- Farther downstream, where numerous tributaries may have joined, forming a river, the water is generally warmer and more turbid.
- An estuary is a transition area between river and sea with very complex flow patterns.
- An intertidal zone is periodically submerged and exposed by the tides, twice daily on most marine shores.
- The oceanic pelagic biome is a vast realm of open blue water, constantly mixed by wind-driven oceanic currents.
- Reef building corals are limited to the photic zone of relatively stable tropical marine environments with high water clarity
- A coral reef, which is formed largely from the calcium carbonate skeletons of corals, develops over a long time on oceanic islands
- The marine benthic zone consists of the seafloor below the surface water of the coastal zone and the offshore zone.
- Climate largely determines the distribution and structure of terrestrial biomes
- A climograph is a plot of the temperature and precipitation in a particular region.
- Vertical stratification is an important feature of terrestrial biomes
- In many forests, the layers consist of the upper canopy, the low-tree stratum, the shrub understory, the ground layer of herbaceous plants, the forest floor, and the root layer.
- The area of intergradations between the boundaries of different biomes are called an ecotone, may be wide or narrow.
- Terrestrial biomes
- Tropical rain forests is a forest with relatively constant of 200 to 400 cm annual rainfall.
- Desert landscapes are dominated by low, widely scattered vegetation; the proportion of the bare ground is high compared with other terrestrial biomes.
- Savanna is piece of land that's warm year-round at 24 - 29oC, with scattered trees and thorny grass
- Chaparral occurs in the midlattitude coastal regions on several continents.
- The veldts of South Africa, the puszta of Hungary, the pampas of Argentina, the steppes of Russia and plains and prairies of central North America are all temperate grassland.
- Coniferous forest is the largest terrestrial biome on Earth
- Temperate Broadleaf forest has distinct, highly diverse, vertical layers.
- Tundra covers expansive areas of the Arctic, amounting to 20% of Earth's land surface.
Concept Check 50.1
- Ecology is the scientific study of the interactions between organisms and the environment. Environmentalism is advocating for the protection or preservation of the natural environment. Ecology helps human to understand the current and past environmental problems caused by humans and how humans could work together and change the world.
- The hawks feeding on the mice would slowly change the surviving mice's gene on the skin and fur camouflage. Event of an ecological time scale can change the gene pools of a species in an evolutionary time scale.
- In population ecology, an ecologist might study the distribution and abundance of red kangaroos in Australia. In community ecology, an ecologist might study changes in which plant species are most abundant in a forest following a wildfire.
Concept Check 50.2
- The human transplant of a kind of plants is an expansion of a species' distribution by changing its dispersal. When a human gave protection to a species of plant or animal from predators, the species' biotic interactions are altered.
- The sun's heating of Earth's surface influence global climate patterns by distributing heat unevenly across the earth, resulting in varying temperatures and amount of light, the circulations of winds, and rain. For example, the tropic receives more sunlight than Arctic Circle, and thus the climates are different.
Concept Check 50.3
- Stoneflies would more likely to live in oligotrophic lakes because of the high concentration of oxygen.
- Phytoplankton is the dominant photosynthetic organisms of the oceanic pelagic biome because the benthic zone is too deep underwater for the sunlight to reach, so there would be a low rate of photosynthesis there.
Concept Check 50.4
- Deserts have a higher temperature than dry tundra.
- The biome I live in is desert because I receive very little rainfall, and the temperature is very high. The temperature also varies quickly between day and night. Yes, since I live in Los Angeles, California, I am basically surrounded by a huge desert that covers all the way to Nevada. However, this does not reflect my actual surroundings, because the home I live in it's another environment separated from the outside. Home, sweet home.
- C. landscape ecology
- C. dispersal occurs only on an evolutionary time scale
- D. a loss of seasonal variation at northern and southern latitudes
- A. in biomes at different latitudes
- D. regulating the pH of freshwater biomes and terrestrial groundwater
- B. aphotic zone
- D. eutrophic lakes are richer in nutrients
- D. vegetation demonstrating stratification
- tropical forests - nearly constant day length and temperature
- A. tropical rain forest
The animals or plants' adaption to the place they live and reproduce could cause changes within their habits and genes based on their flexibility to the surroundings. The small changes in the ecological times would play a large role in evolutionary time because the species are evolving accordingly to the environment they live in. Generally, ecological and evolutionary times always correspond.
Examples are that the hawks feeding on mice would immediately kill the preys with a skin color that's easily seen according to the environmental background. And the surviving mice would have a dark skin, and thus the children of those mice would also have darker skin. The hawks' eyes are also getting better and better at identifying dark skin mice, and thus kill and eat the prey they can see except for those mice with very dark skin. This process goes on for a long time, and in the end there would be mice with very black camouflage fur and hawk with very sharp eyes.
By taking seeds from the plant species growing at the low elevation, you can plant it at a high elevation and compare the differences in growth of the seed you planted with the rest of this species at the low elevation. You can do the same for the plants for the high elevations. If the first experiment's result is that the plant from low elevation's growth is the same as it was in high elevation, the species would be considered as developmental flexible to the condition it's under.
Chapter 51 Behavioral Ecology
- Behavioral ecologists distinguish between proximate and ultimate causes of behavior
- What is behavior?
- Behavioral traits are as much a part of an animal's phenotype as the length of its appendages or the color of its fur.
- Most of what we call behavior is the visible result of an animal's muscular activity.
- Proximate and ultimate questions
- Proximate questions about behavior focus on the environmental stimuli, if any, that trigger a behavior, as well as the genetic, physiological and anatomical mechanisms underlying a behavioral act.
- Ultimate questions address the evolutionary significance of a behavior.
- Ethology, the scientific study of how animals behave, particularly in their natural environments.
- Fixed action patterns are a sequence of unlearned behavioral acts that is essentially unchangeable and, once initiated, is usually carried to completion.
- A FAP is triggered by an external sensory stimulus known as a sign stimulus.
- Imprinting is a type of behavior that includes both learning and innate components and is generally irreversible.
- Imprinting is distinguished from other types of learning by having a sensitive period, a limited phase in an animal's development that's the only time when certain behaviors can be learned.
- Many behaviors have a strong genetic component
- Direct movements are the movements of animals controlled by genes.
- Kinesis is a simple change in activity or turning rate in response to a stimulus.
- Taxis is a more or less automatic, oriented movement toward or away from some stimulus.
- Animal signals and communications
- Signal is a behavior that causes a change in another animal's behavior.
- Communication is the transmission of, reception of, and response to signals.
- Many animals that communicate through odors emit chemical substances called pheromones. This is a form of chemical communication.
- Auditory communication is for example, the songs of birds.
- Behavioral research has uncovered a variety of mammalian behaviors that are under relatively strong genetic control, as well as the physiological mechanisms for these behaviors.
- Environment, interacting with an animal's genetic make up, influences the development of behaviors
- Dietary influence on mate choice behavior
- One example of environmental influence on behavior is the role of diet in mate selection by Drosophila Mojavensis, which mates and lays its eggs on the rotting tissues of cactus.
- Learning is the modification of behavior based on specific experiences.
- Habituation is a loss of responsiveness to stimuli that convey little or no information.
- Spatial learning is the modification of behavior based on experience with the spatial structure of the environment, including the locations of the nest sites, hazards, food, and prospective mates.
- Cognitive map is an internal representation, or code, of the spatial relationships between objects in an animal's surroundings.
- Associative learning is the ability of many animals to associate one feature of the environment with another.
- A type of associative learning is called classical conditioning, in which an arbitrary stimulus, in this case an odor, is associated with a reward or punishment.
- Cognition and problem solving
- Cognition is the ability of an animal's nervous system to perceive, store, process, and use information gathered by sensory receptors.
- Cognitive ethology is the study of animal cognition.
- Behavioral traits can evolve by natural selection
- When behavioral variation within a species corresponds to variation in environmental conditions, it may be evidence of past evolution
- An example of genetically based variation in behavior within a species is pretty selection by the garter snake Thamnophis elegans.
- Foraging is behavior associated with recognizing, searching for, capture, and consuming food.
- Foraging behavior is the food obtaining behavior, not only eating, but also nay mechanisms an animal uses to recognize, search for, and capture food items.
- Optimal foraging theory views foraging behavior as a compromise between the benefits of nutrition and the costs of obtaining food, such as the energy expenditure or the risk of being eaten by a predator while foraging.
- Risk of predation
- An animal that feeds in a way that maximizes energy benefits and minimizes energy coasts without regard to its risk of becoming a meal for some predator has not optimized its foraging behavior.
- Mating behavior and mate choice
- Mating systems and parental care
- Promiscuous mating is when no strong pair bonds or lasting relationships
- Monogamous mating is when one male mates with one female
- Polygamous mating is when an individual of one sex mates with several of the other
- Polygyny is when one males mates with many females
- Polyandry is when one female mates with several males
- Sexual selection and mate choice
- Mate choice by females may play a central role in the evolution of male behavior and anatomy through intersexual selection
- Male competition for mates
- Agonistic behavior is an often ritualized contest that determines which competitor gains access to a resource, such as food or mates.
- Applying game theory evaluates alternative strategies in situations where the outcome depends not only on each individual's strategy but also the strategies of other individuals.
- The concept of inclusive fitness can account for most altruistic social behavior
- Altruism is selflessness.
- Inclusive fitness is the total effect an individual has on proliferating its genes by producing its own offspring and by providing aid that enables own offspring and by providing aid that enables other close relatives, who share many of those genes, to produce offspring.
- Hamilton's Rule and Kin Slection
- Coefficient of relatedness equals the probability that if two individuals share a common parent or ancestor, a particular gene present in one individual will also be present in the second individual.
- Kin selection is the natural selection that favors this kind of altruistic behavior by enhancing reproductive success of relatives.
- Reciprocal altruism is the commonly invoked to explain altruism between unrelated humans.
- Social learning is the learning through observing others.
- Mate choice copying is a behavior in which individuals in a population copy the mate choice of others.
- Evolution and human culture
- Human culture is related to evolutionary theory in the discipline of sociobiology, whose main premise is that certain behavioral characteristics exist because they are expressions of genes that have been perpetuated by natural selection.
Concept Check 51.1
- The proximate question would be how the squirrel makes that loud call. Another proximate question would be how development influences the squirrel's calling behavior. The two ultimate questions would be why does the squirrel make this kind of call, and why does this loud call increase the squirrels' survival and fitness.
- This example given in the question is a fixed action pattern. A proximate question would be the egg or white ball outside of the net may each be a sign stimulus that cause the mother goose to retrieve it back to the nest. Ultimate explanation would be that the mother's action can increase the offspring's survival and fitness.
Concept Check 51.2
- I think both nature and nurture exhibit great influences on the development of behaviors. However, I don't think either of them possesses absolute control over the behaviors. They work together.For example, in human world, teachings from the society are not always influencing people's behavior. Police officers tell the students not to do drugs, but some still do. And yet the genes of the humankind cause the children to be somewhat like their parents, but never exactly similar because the world is changing, and thus the societal influences on parents and children are different.
- The researchers cross mated migratory blackcaps from southern Germany with nonmigratory blackcaps from Cape Verde and subjected their offspring to environments simulating one location or the other. The percentage that's raised in both conditions that shows migratory restlessness can conclude whether this migration behavior is under genetic control or not.
Concept Check 51.3
- Cognitive map can develop a specific code or representation of the surroundings, which is helpful for the animals in their spatial learning. It's almost like a set of index cards of their locations.
- Diet, society, and learning (from experiences individual receives) are the three ways in which an animal's environment can influence the development of its behavior.
- Associative learning explains why unrelated distasteful or stinging insects have colors. Because those colors became a warning sign of the bad taste and stings. The animals that had once gotten a sting or a bad state in their mouths would be associated with those bugs. They learned that the color would be an indicator of bad taste or stings.
Concept Check 51.4
- The amount of food available to the two garter snake habitats would change the snakes' eating habit. The snakes that live in the area with less food would be learned to eat new foods. Thus the snake that lived in the coastal areas feed on slugs because it's available to them. This behavior of eating slugs became a part of the genes of the coastal garter snake evolved by natural selection.
- To show the different degrees of aggressiveness are due to variations in genes.
- The conclusions are that the blackcap migratory patterns are that migratory orientations are based upon different genes they possess. The laboratory-raised offspring of British and German blackcaps have different migratory orientations, and it's upon different genes.
Concept Check 51.5
- Paternity's chance of conceiving the offspring is higher than the external fertilization.
- The mule deer are at forest edges, they spend significantly more time scanning their surroundings than when they are in either open areas or forest interiors. The evidence indicates that mule deer foraging behavior reflects variation in predation risk more than variation in food availability. The optimal foraging theory explains that mule deer focus more on the cost of getting food (risks of being eaten).
- Because if a male has strong, healthy body and beautiful colors, the chances are that its children would also be healthy and have a higher chance of survival.
Concept Check 51.6
- The ultimate cause for altruistic behavior is that by helping kin, the reproductive success of the entire species is increased.
- The cooperative behavior among nonrelated animals could be explained that the helper expects favors returned in the future. There could also be some benefits resulting from helping a species.
- The changes in behaviors produced by cross fostering of white-footed mice and California mice could extend into the future generations because it's genetically based.
- D. innate behaviors are expressed in most individuals in a population across a wide range of environmental conditions
- D. a fish orienting itself into a river current
- D. spawning in the home stream results in higher survival of young salmon
- A. the annual addition of new syllables to a canary's song repertoire
- C. the cultural tradition of using stones to crack nuts has arisen in only some populations
- A. in each individual, the form of the behavior is determined entirely by genes
- D. it usually results in death or serious injury to one or both of the competitors
- C. polyandry
- B. natural selection favors altruistic acts when the resulting benefit to the beneficiary, multiplied by the coefficient of relatedness, exceeds the cost to the altruist
- C. much human behavior has evolved by natural selection
The human behavior of "falling in love" before mating should be considered less meaningful in an evolutionary base. The evolution involves upon the reproductive ability of the animals. So on an evolutionary base, the human feelings do not matter since reproduction of a stronger generation is the key to natural selection and evolution and mutation.
The helpers that assist the birds to mate were probably doing it out of altruism for the whole species, because there must be more mating birds than helpers. The helpers were assisting the mating birds simply so there could be more chance of survival for the whole species.
I would test my hypothesis by studying the percentage of helpers compared to the mating birds. And then I would observe if the helpers would receive anything in return from the mating birds. If the helpers did not receive any helps back from the mating birds and the percentage of helpers to mating birds are basically the same every generation, then my hypothesis is correct.
Chapter 52 Population Ecology
- Population ecology is the study of populations in relation to the environment, including environmental influences on population density and distribution.
- A population is a group of individuals of a single species living in the same general area
- Dynamic biological processes influence population density, dispersion, and demography.
- Population density, the number of individuals per area or volume, results from the combination of births, deaths, immigration, and emigration.
- Dispersion is the pattern of spacing among individuals within the boundaries of the population
- Environmental and social factors influence the spacing of individuals
- In clumped patterns, individuals are aggregated in patches
- In uniform patterns, individuals are evenly spaced
- Animals often exhibit uniform dispersion as a result of antagonistic social interactions, such as territoriality, the defense of a bounded physical space against encroachment by other individuals
- In random dispersion, individuals are unpredictably spaced, and the position of each individual is independent of others
- This occurs in the absence of strong attraction or repulsions among individuals of a population
- Populations grow from births and immigration and shrink from deaths and emigration
- Immigration is the influx of new individuals from other areas
- Emigration is the movement of individuals out of a population
- Demography is the study of the vital statistics of populations and how they change over time
- Of particularly interest to demographers are birth rates and how they vary among individuals and death rates
- Life tables are age-specific summaries of the survival pattern of a population
- the best way to construct one is to follow the fate of a cohort, a group of individuals of the same age, from birth until all are dead
- A survivorship curve is a plot of the proportion or numbers in a cohort still alive at each age
- Type I curve is flat at the start, reflecting low death rates during early and middle life, then drops steeply as death rates increase among older age group
- Type II curves are intermediate, with a constant death rate over the organism's life span
- Type III curve drops sharply at the start, reflecting very high death rates for the young, but the flattens out as death rates decline for those individuals that have survived to a critical age
- Reproductive tables, or fertility schedules, are age specific summaries of the reproductive rates in a population
- The traits that affect an organism's schedule of reproduction and survival from birth through reproduction to death make up its life history.
- They are evolutionary outcomes reflected in the development, physiology, and behavior of an organism.
- Semelparous organisms reproduce a single time and die.
- Iteroparous organisms produce offspring repeatedly.
- Life history traits such as brood size, age at maturity, and parental caregiving represent trade-offs between conflicting demands for limited time, energy, and nutrients.
- The exponential model describes population growth in an idealized, unlimited environment.
- The per capita birth rate (b) is the number of offspring produced per unit time by an average member of the population The per capita death rate (m) is the number of individuals of a population that die per unit time
- The per capita rate of increase (r), or a population's growth rate, equals birth rate minus death rate.
- R = b - m
- Growth occurs when r>0 and decline occurs when r<0
- Zero population growth occurs when the per capita birth and death rates are equal (r = 0)
- Exponential population growth is population increase under the ideal conditions of abundant food and the freedom to reproduce at physiological capacity
- Under these conditions, the per capita rate of increase may assume the maximum rate for the species, called the intrinsic rate of increase and denoted as rmax
- The exponential growth equation dN/dt = rmaxN represents a population's potential growth in an unlimited environment. dN denotes change in population, while dt denotes change in time
- The logistic growth model includes the concept of carrying capacity.
- Carrying capacity (K) is the maximum population size that a particular environment can support
- It is not fixed, but varies over space and time with the abundance of limiting resources
- Exponential growth cannot be sustained for long in any population.
- A more realistic population model limits growth by incorporating carrying capacity
- According to the logistic equation dN/dt = rmaxN (K - N)/K, growth levels off as population size approaches the carrying capacity.
- The logistic model fits few real populations, but it is useful for estimating possible growth.
- K-selection is density-dependent selection
- r-selection is density-independent selection
- Populations are regulated by a complex interaction of biotic and abiotic influences.
- In density-dependent population regulation, death rates rise and birth rates fall with increasing density
- In density-independent regulation, birth and death rates do not change with increasing density.
- Density-dependent changes in birth and death rates curb population increase through negative feedback and can stabilize a population near its carrying capacity.
- Limiting factors include intraspecific competition for limited food or space, increased predation, disease, stress due to crowding, and buildup of toxins.
- The study of population dynamics focuses on the complex interactions between biotic and abiotic factors that cause variation in population size.
- Immigration and emigration influences populations more when a group of populations is linked, forming a metapopulation.
- Human population growth has slowed after centuries of exponential increase
- Since 1650, the global human population has grown exponentially, but within the last 40 years, the rate of growth has fallen by nearly 50%.
- Currently the global population numbers over 6 billion
- Two possible configurations for a stable population are:
- Zero population growth = high birth rate - high death rate
- Zero population growth = low birth rate - low death rate
- The movement toward the second state is called the demographic transition.
- Differences in age structure show that while some nations are growing rapidly, others are stable or declining in size.
- Infant mortality is the number of infant deaths per 1000 live births and life expectancy at birth, the predicted average length of life at birth, vary widely among human populations.
- The ecological footprint concept summarizes the aggregate land and water area appropriated by each nation to produce all the resources it consumes and to absorb all the waste it generates
- The ecological capacity is the actual resource base of each country
- Humans could also run out of nonrenewable resources, such as certain metals and fossil fuels.
Concept Check: 52.1
- The species of bird that's highly territorial have uniform pattern of dispersion. The species of the bird that live in flocks is going to have a clumped pattern of dispersion.
- The survivorship pattern is likely to be type III because most of the eggs die before they can reproduce.
- The average would be 50%
Concept Check: 52.2
- The spring fed river is more likely to support many species of iteroparous animals because the populations are more stable there. The competitions for nutrients are also less intense, and the young have a better chance of survive and reproduce.
Concept Check: 52.3
- A constant increasing population produces a growth graph that is J-shaped curve because the population is increasing exponentially.
- In a newly formed volcanic island is where a plant population is more likely to grow exponentially because there are more spaces and less competition for light and nutrients.
Concept Check: 52.4
- A population that fits the logistic growth model increases more rapidly at intermediate size than at small or large sizes because when the population is below the carrying capacity, there are not a lot of parental organisms to reproduce. However, when the population is near the carrying capacity, there are not enough resources to support everyone in the population.
Concept Check: 52.5
- The three density-dependent factors that limit population size are 1. Competition for resources that's becoming more intense as the population grows. Therefore the chance of survival is getting lower.
- Diseases are killing more quickly because as population grows, the virus or bacteria can quickly spread.
- Individuals competing for territorial spaces.
Concept Check: 52.6
- A population with a high proportion of young will be declining. A population with a high proportion of old and a low proportion of young will be remaining stable.
- Carrying capacity is the amount of people a nation can support based on its ecological resources that could provide for everyone in the nation. The ecological footprint concept summarizes a nation's land and water area to use the sufficient amount of resources it consumes and to recycle all the waste.
- C. the members of the population are competing for access to a resource
- C. determine the birth rate and death rate of each group in a population
- C. population growth is zero when N equals K
- D. may change as environmental conditions change
- D. iteroparous; K-selected
- E. about six times higher
- C. the most obvious, plausible hypothesis about the cause of population cycles is not necessarily the correct one
- D. 6 billion
- C. life history is r-selected
- D. the ecological footprint of the United States is larger than the ecological capacity of its land
In desert or environments where there aren't enough nutrients for a seasonal or annual reproduction, the semelparity would be favored the most. The iteroparity just cannot reproduce as frequently in the desert than in a nutrient-sufficient environment.
However, on the contrary, in jungle or rainforest, the semelparity would be at a disadvantage because the one time reproduction does not give the seed high probability to grow themselves since there were competitions for water and sunlight. The iteroparity would be greatly beneficial at the nutrient-sufficient area because every year it produces new seeds to grow, and thus increases the chance of growing and competing with other plants.
I grow a type of tree in my backyard, and grow fungi too. After a while, I would begin to grow more of those trees. I would observe every day the influences of the increasing density of the backyard on the growth of the fungi.
I need to collect data of the how fast the fungi are spreading. I also need to observe the amount of fungi to the growth of more trees. If my hypothesis is correct, then the fungi's growth should be directly proportional the growth of the backyard tree density.
Chapter 53 Community Ecology
- A community's interactions include competition, predation, herbivory, symbiosis, and disease.
- Interspecific competition occurs when species compete for a particular resource that is in short supply.
- Competitive exclusion principle states that even a slight reproductive advantage will eventually lead to local elimination of the inferior competitor.
- Ecological niches is the sum total of a species' use of biotic and abiotic resources in its environment
- Two species cannot coexist in a community if their niches are identical
- Ecologically similar species can coexist in a community if there are one or more niches are identical.
- Resource partitioning is the differentiation of niches that enables similar species to coexist in a community.
- Character displacement is the tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species.
- Predation refers to a +/- interaction between species in which one species, the predator, kills and eats the other, the prey.
- Cryptic coloration or camouflage makes prey difficult to spot.
- Aposematic coloration is an effective chemical defense often exhibit bright warning coloration.
- Batesian mimicry is a palatable or harmless species mimics an unpalatable or harmful model.
- Herbivory refers to a +/- interaction in which an herbivore eats parts of a plant or alga.
- Parasitism is a +/- symbiotic interaction in which one organism, the parasite, derives its nourishment from another organism, its host, which is harmed in the process.
- Endoparasites are parasites that live within the body of their host.
- Ectoparasites are parasites that feed on the external surface of a host.
- Parasitoidism is a particular type of parasitism that usually laid eggs on or in living hosts. The larvae then feed on the body of the host, eventually killing it.
- Pathogens, or disease-causing agents, are bacteria, viruses, or protists, but fungi and prions may also be pathogenic.
- Mutualism is an interspecific interaction that benefits both species.
- Commensalism is defined as an interaction between species that benefits one of the species but does not harm nor helps the other.
- Coevolution is the evolutionary adaptations of two interacting species.
- Dominant and keystone species exert strong controls on community structure
- Species diversity of a community is the variety of different kinds of organism that make up the community.
- Species richness is the total number of different species in the community
- Relative abundance of the different species, the proportion each species represents of the total individuals in the community.
- Trophic structure is the structure and dynamics of a community on the feeding relationships between organisms.
- Food webs summarize the tropic relationships of a community by diagramming who eats whom.
- Each food chain within a food web I usually only a few links long
- Energetic hypothesis suggests that the length of a food chain is limited by the inefficiency of energy transfer along the chain.
- Dynamic stability hypothesis proposes that long food chains are less stable than short chains.
- Species with a large impact
- Dominant species are those species in a community that are the most abundant or that collectively have the highest biomass.
- Invasive species can attain in environments lacking their natural predators and pathogens.
- Keystone species exert strong control on community structure not by numerical might but by their pivotal ecological role.
- Facilitators have positive effects on survival and reproductions of some of the other species in the community by altering the structure or dynamic s of the environment.
- Bottom-up and top-down controls
- Bottom-up model postulates a unidirectional influence from lower to higher trophic levels.
- Top-down model postulates that the influence moves in the opposite direction.
- Disturbance influences species diversity and composition
- Disturbance is an event, such as a storm, fire, flood, drought, overgrazing, or human activity, that changes a community, removes organisms from it, and alters resource availability.
- Intermediate disturbance hypothesis suggests that moderate levels of disturbance can create conditions that foster greater species diversity than low or high levels of disturbance.
- Ecological succession is the disturbed area being colonized by a variety of species which are gradually replaced by other species, which are in turn replaced by still other species.
- Primary succession is when the ecological succession begins in a virtually lifeless area where soil has not yet formed, such as on a new volcanic island or on the rubble left behind by a retreating glacier.
- Secondary succession occurs when an existing community has been cleared by some disturbance that leaves the soil intact.
- Biogeograhic factors affect community biodiversity
- Equatorial-Polar gradients
- Evapotranspiration is the evaporation of water from soil plus the transpiration of water from plants.
- Species-area curve quantifies what probably seems obvious: All other factors being equal, the larger the geographic area of a community, the greater the number of species.
- Contrasting views of community structure are the subject of continuing debate
- Integrated and individualistic hypothesis describes a community as an assemblage of closely linked species, locked into association by mandatory biotic interactions that cause the community to function as an integrated unit -in effect, as a superorganism.
- Individualistic hypothesis depicts a plant community as a chance assemblage of species found in the same area simply because they happen to have similar abiotic requirements.
- Rivet and redundancy models
- Rivet model of communities reincarnates the integrated model that Clements suggested for plant communities.
- Redundancy model shows that most of the species in a community are not tightly associated with one another, and the web of life is very loose.
Concept Check 53.1
- Interspecific competition, predation, and mutualism differ in their effects on the interacting populations of two species in that interspecific competition harms both species, predation benefits one species at the expense of the other, and mutualism benefits both species.
- One species would become locally extinct, while the other is going to be better at utilizing resources.
- Batesian mimicry is not an example of coevolution, as only one species changes to adapt to the other. The other species is not affected by the mimic.
Concept Check 53.2
- The two components of species diversity are species richness, the total number of species in the community, and relative abundance, the proportion each species represents of the total individuals in the community. Two communities that contain the same number of species can differ in species diversity because proportions of the species are various.
- The energetic hypothesis proposes the food chains are generally short because of the inefficiency of energy transfer along the chain. The dynamic stability hypothesis proposes that long food chains are less stable than short chains. The energetic hypothesis predicts that food chains should be relatively longer in habitats of higher photosynthetic productivity. The dynamic stability predicts that the food chain should be shorter in unpredictable environment.
- A dominant species' effect on community structure differs from a keystone species' effect in that dominant species have major effects on communities because of their high abundance. Keystone species have major effects on community structure because of their ecological roles.
- Top-down and bottom-up controls on community organization differ in that in top-down controls, influence flows from the top of the trophic chain down to the primary producers. In bottom-up controls, influence flows up the trophic chain from the primary producers.
Concept Check 53.3
- High level disturbance would prevent the species from recovering. The low level disturbance allows the dominant species to locally wipe out weak species. An intermediate disturbance would prevent the dominant species to exclude less competitive species.
- Primary succession is the process of ecological succession begins in a virtually lifeless area where soil has not yet formed. Secondary succession occurs when an existing community has been cleared by some disturbance that leaves the soil intact.
- At the time of the succession, the early species might facilitate the later species by increase the chance for reproduction or keep the soil moisture or shelter to seedlings from harsh environmental conditions.
Concept Check 53.4
- Species richness is directly proportional to the size of the area.
- Species diversity is greater in tropical regions than in temperate and Polar Regions because there is a longer evolutionary history and greater solar energy input and water availability in tropical regions. In Polar Region, seriously come on, there are too much ice, not enough sunlight, and thus not much animals or plants could withstand the environment.
- The smaller the size of the island, the less chance there is of species finding the island and settling there. The farther away the island is from the mainland, the chance of immigration is also smaller
Concept Check 53.5
- The integrated hypothesis claims that the species within a community are sealed within particular biotic interactions. The rivet model suggests that all the species in a community are linked together in a tight web of interactions, so that the loss of even a single species could strongly affect the whole web.
The individualistic hypothesis proposes that communities are loosely organized associations of independent species with the same abiotic requirements. The redundancy model proposes that most of the species in a community are not strongly related or associated with one another and that if a species is lost from a community, another species will rise up to fill the position of the lost species.
- C. trophic structure
- D. two species with the exact same niche cannot coexist in a community
- B. prettying on the community's dominant species
- C. most of the energy in a trophic level is lost as it passes to the next higher level
- D. all species in a natural community contribute to the community's integrity
- C. increased by moderate levels of disturbance
- B. two poisonous frogs with similar color patterns
- D. effect of grazing intensity by bison on plant species diversity
- B. tropical regions have more available water and higher levels of solar radiation
- C. large and close to a mainland
The character displacement is that the species become more different when they are involved in interspecies competition. The adaption to the interspecies competition of the particular organisms do not necessary means that they are becoming more divergent. The competing species could be evolving to be fit for competition, yet that does not mean that they are becoming more and more different. On the contrary, they may become more similar.
The plant that became more abundant in the experimental plot was able to do so because it was not being consumed by the kangaroo rat. Without a predator, the plant was able to increase its abundance and competitively exclude the other species. In this scenario, the kangaroo rat may be considered a keystone species because removal of it drastically alters the floral species composition.
Chapter 54: Ecosystems
- Ecosystem ecology emphasizes energy flow and chemical cycling
- Trophic relationships
- Primary producers of the ecosystem are the trophic level that ultimately supports all others consists of autotrophs.
- Primary consumers are the herbivores, which eat plants and other primary producers.
- Carnivores that eat herbivores are secondary consumers and carnivores that eat other carnivores are tertiary consumers.
- Detritivores, or decomposers, are consumers that get their energy from detritus, which is the nonliving organic material, such as the remains of dead organisms, feces, fallen leaves, and wood
- Detritivores decompose the organic material in an ecosystem and transfer the chemical elements in inorganic forms to abiotic reservoirs such as soil, water, and air.
- Physical and chemical factors limit primary production in ecosystems
- Ecosystem energy budgets
- Every day, Earth is bombarded by about 1022 joules of solar radiation.
- Gross and Net Primary Production
- Gross primary production is the amount of light energy that is converted to chemical energy by photosynthesis per unit time.
- Net primary production is equal to gross primary production minus the energy used by the primary producers for respiration.
- Primary production in marine and freshwater ecosystems
- More than half of the solar radiation is absorbed in the first meter of water. Even in clear water, only 5-10% of the radiation may reach a depth of 20m.
- A limiting nutrient is the element that must be added in order for production to increase in a particular area.
- Eutrophication is the process of phytoplankton communities that had been dominated by diatoms or green algae became dominated by cyanobacteria.
- Actual evapotranspiration is the annual amount of water transpired by plants and evaporated from a landscape.
- Energy transfer between trophic levels is usually less than 20% efficient
- Secondary production is the amount of chemical energy in consumers' food that is converted to their own new biomass during a given time period.
- Production efficiency is the fraction of energy stored in food that is not used for respiration.
- Trophic efficiency is the percentage of production transferred from one trophic level to the next.
- The green world hypothesis states that terrestrial herbivores consume relatively little plant biomass because they are held in check by a variety of factors, including predators, parasites, and disease.
- Plants have defenses against herbivores, including spines and noxious chemicals.
- Nutrients, not energy supply, usually limit herbivores. Animals need certain nutrients, such as organic nitrogen, that plants tend to supply in relatively small amount.
- Abiotic factors limit herbivores. Unfavorable seasonal changes in temperature and moisture are examples of abiotic factors that can set a carrying capacity for herbivore in a particular environment far below the number that would strip vegetation there.
- Intraspecific competition can limit herbivore numbers. Territorial behavior and other consequences of competition may maintain herbivores' population densities below what the vegetation could feed.
- Interspecific interactions keep herbivore densities in check. The green world hypothesis postulates that predators, parasites, and disease ar e the most important factors limiting the growth of herbivore populations.
- Biological and geochemical processes move nutrients between organic and inorganic parts of the ecosystem
- Biogeochemcial cycles are nutrient circuits involve both biotic and abiotic components.
- A chemical's specific route through a biogeochemical cycle varies with the particular element and the trophic structure of the ecosystem.
- Nutrient cycles
- The water cycle involves the evaporation of liquid water by solar energy, condensation of water vapor into clouds, and precipitation.
- The carbon cycle involves the photosynthesis by plants and phytoplankton removes substantial amounts of atmospheric CO2 each year.
- The major pathway for nitrogen to enter an ecosystem is via nitrogen fixation, the conversion of N2 by bacteria to forms that can be used to synthesize nitrogenous organic compounds.
- The phosphorus cycle: weathering of rocks gradually adds phosphate to soil. Phosphate is required by the organisms in bones and teeth.
- The human population is disrupting chemical cycles throughout the biosphere
- Nutrient enrichment
- After natural vegetation is cleared from an area, the existing reserve of nutrients in the soil is sufficient to grow crops for some time without nutrient supplementation.
- Critical load is the amount of added nutrient, usually nitrogen or phosphorus that can be absorbed by the plants without damaging ecosystem integrity.
- Cultural eutrophication is the human intrusion that has disrupted freshwater ecosystems.
- Biological magnification is a trophic process in which retained substance become more concentrated with each link in the food chain
- Atmospheric carbon dioxide
- Since the Industrial Revolution, the concentration of CO2 in the atmosphere has been increasing as a result of the combustion of fossil fuels and the burning of enormous quantities of wood removed by deforestation.
- Greenhouse effect is the warming of Earth due to the atmospheric accumulation of carbon dioxide, which absorbs reflected infrared radiation and re-reflects some of it back toward Earth
Concept Check 54.1
- Energy enters the ecosystem as sunlight, and was transferred along the food chain. However, this energy was not only recycled.
- Because energy is lost as heat in any conversion process, there must be a constant of energy replenishment to refill up the energy that's lost.
- The detritivores decomposes stuffs into their original elemental form, and thus it's the beginning and the end of the recycling process. It's a very natural way of dealing with waste.
Concept Check 54.2
- Only a small portion of the sun's radiation is stored by the primary producer because most of the sunlight are reflected rather than absorbed by Earth. Also, the sunlight is composed of different wavelength, and therefore not 100% of the sunlight is able to go into photosynthesis.
- The ecologists can control the availability of light, nutrients, water, or the degree of moisture.
- The ocean account for so many primary productions because of its enormous area.
- An ecosystem's net primary production equals the gross primary production minus the energy used by primary producers for respiration.
Concept Check 54.3
- The net secondary production is 20J, and its production efficiency is 40%.
- Detritivores consumes the rest of the plant biomass after they are turned into animal poops.
- The production pyramid has the same general shape as the biomass pyramid in most ecosystems because the primary producers have the largest biomass. The two pyramids are different in water, because phytoplankton supports primary consumers of higher biomass.
Concept Check 54.4
- The molecule of H2O was evaporated from the ocean, and turned into clouds floating in the sky. And then the cloud precipitated and rained that molecule of H2O down into the mountain. The molecule sank into the soil and became a part of an underground river and flow back into the ocean.
An animal died and a carbon molecule went from its body to the ocean. It's collected and burned as fuel by human into the air. The plants got that carbon molecule back to Earth through photosynthesis. A rabbit ate that plant, and a wolf ate that rabbit. Now the carbon molecule is back to the animal's body.
A nitrogen molecule from the atmosphere went into the soil with nitrogen-fixing bacteria, and became ammonified by decomposers, and became nitrified by nitrifying bacteria. It was denitrified by denitrifying bacteria back into the air.
The phosphorus was weathered from the rocks into the stream, became absorbed by plants, and consumed by animals. The phosphorus then goes into soil after the animal's decomposition, and goes into the ocean. The sedimentations were geologically uplifted into the ground.
- Because the plants that absorb the nitrate were removed as a result of deforestation of a watershed, and all the nitrates ended up in the water.
Concept Check 54.5
- The addition of excess nutrients would increase the amount of algae, and thus increase the large amount of algae consumers. The water oxygen would be not enough to support such a large population.
- Trees absorb nutrients and bad stuffs from the water. If all trees are removed, the lakes nearby would be contaminated because nothing is absorbing harmful elements anymore.
- At a lower trophic level, the biological magnification increases the concentration in the food chain.
- The thawing of the frozen soils would decompose the organic matters, and release a huge amount of carbon dioxide that would worsen global warming.
- C. zooplankton - primary producer (incorrect)
- E. eating grain fed beef is an inefficient way to obtain the energy captured by photosynthesis
- D. converting ammonia to nitrate, which is absorbed by plants
- E. calcium levels remained high in the soil of deforested areas
- D. the burning of larger amounts of wood and fossil fuels
- A. toxic chemicals in the environment pose greater risk to top-level predators than to primary consumers
- B. an open ocean
- C. organic matter decomposes more rapidly and plants assimilate soil nutrients more rapidly in the tropics
- D. nitrogen is the limiting nutrient in these waters
- C. the rate of decomposition in the ecosystem
Evolution is a change in the genetic makeup of a population over time. The genetic diversity of an ecosystem is based on the genetic changes of the species. As the species are changing, the ecosystem could also be considered to be changing. The ecosystem's change of genetic makeup should also be considered as a form of evolution.
However, the ecosystem evolution doesn't correspond with Darwinian evolution is because ecosystem has no competition, and thus no natural selection.
I can measure the primary production in the 1st pond with falling leaves and with the second pond with no leaves falling unto it because I would set up a net over it. I would observe the differences in the primary productions of these two ponds, and conclude the influences of leaf falling effects based on these differences.
Chapter 55: Conservation Biology and restoration ecology
Conservation biology integrates ecology, physiology, molecular biology, genetics, and evolutionary biology to conserve biological diversity at all levels.
Restoration ecology applies ecological principles in effort to return degraded ecosystems to conditions as similar as possible to their natural, predegraded state.
- Human activities threaten Earth's biodiversity
- The three level of biodiversity
- Genetic diversity comprises not only the individual genetic variation within a population, but also the genetic variation between populations that is often associated with adaptations to local conditions.
- Species diversity
- Endangered species are one that is "in danger of extinction throughout all or significant portion of its range."
- Threatened species are those that are considered likely to become endangered in the foreseeable future.
- Ecosystem diversity
- Because of the network of community interactions among populations of different species within an ecosystem, local extinction of one species has a negative impact on the overall species.
- Biodiversity and human welfare
- The loss of species also means the loss of genes. Each species has unique genes, and biodiversity represents the sum of all the genomes of all organisms on Earth.
- Such enormous genetic diversity has the potential for great human benefits.
- Ecosystem services encompass all the processes through which natural ecosystems and the species they contain help sustain human life on Earth.
- Four major threats to biodiversity
- Human alteration of habitat is the single greatest threat to biodiversity throughout the biosphere.
- Introduced species are those that humans move from the species' native locations to new geographic regions.
- Introduced species that gain a foothold usually disrupt their adopted community, often by preying on native organisms or out-competing them for resources.
- Overexploitation refers generally to the human harvesting of wild plants or animals at rates exceeding the ability of populations of those species to rebound.
- Disruption of interaction networks
- II. Population conservation focuses on population size, genetic diversity, and critical habitat
- Small-population approach
- Extinction vortex refers to a small population is prone to positive-feedback loops of inbreeding and genetic drift that draw the population down toward smaller and smaller population size until no individuals exist.
- Minimum viable population is usually estimated for a given species using computer models that integrate many factors. The calculations may include an estimate of how many individuals in a small population are likely to be killed by some natural catastrophe such as a storm.
- Population viability analysis is reasonable predictions of a population's chances for survival.
- The declining population approach focuses on the environmental factors that cause decline, regardless of absolute population size.
- Steps for analyzing declining populations and determining interventions are useful even in complex cases:
- Asses population trends and distribution to confirm that the species is presently in decline or that it was formerly more widely distributed or more abundant
- Study the natural history of this and related species, including reviewing the research literature, to determine the species' environmental requirements
- Develop hypotheses for all possible causes of the decline, including human activities and natural events, and list the predictions of each hypothesis
- Because many factors may be correlated with the decline, test the most likely hypothesis first.
- Apply the results of the diagnosis to management of the threatened species and monitor recovery
- Conserving species often requires resolving conflicts between the habitat needs of endangered species and human demands.
- Landscape and regional conservation aim to sustain entire biotas
- Landscape ecology is to understand past, present, and future patterns of landscape use and to make biodiversity conservation part of land-use planning.
- Movement corridor is a narrow strip or series of small clumps of quality habitat connecting otherwise isolated patches to allow animals to cross human-created barriers.
- Establishing protected areas
- Biodiversity hot spot is a relatively small area with an exceptional concentration of endemic species and a large number of endangered and threatened species.
- Zoned reserve is an extensive region of land that includes one or more areas undisturbed by humans surrounded by lands that have been changed by human activity and are used for economic gain.
- The key challenge of the zoned reserve approach is to develop a social and economic climate in the surrounding lands that is compatible with the long-term viability of the protected core area.
- The continued high rate of human exploitation of ecosystems leads some analysts to predict that considerably less than 10% of the biosphere will ever be protected as nature reserves.
- Restoration ecology attempts to restore degraded ecosystems to a more natural state
- Bioremediation is the use of living organisms, usually prokaryotes, fungi, or plants, to detoxify polluted ecosystems.
- Biological augmentation uses organisms to add essential materials to a degraded ecosystem.
- Because of the newness of restoration ecology as a discipline, the complexity of ecosystems, and the unique features of each situation, restoration
- Sustainable development seeks to improve the human condition while conserving biodiversity
- Sustainable development is the long-term prosperity of human societies and the ecosystems that support them.
- The success of conservation in Costa Rica has involved leadership by the national government as well as an essential partnership between the national government, nongovernment organizations, and private citizens.
- Biophilia is an evolutionary product of natural selection acting on a brainy species whose survival depended on a close connection to the environment and a practical appreciation of plants and animals
Concept Check 55.1
- Because the biodiversity crisis involved the loss of genetic diversity and eventually would become the degradation of the entire ecosystem.
- Habitat destruction could seriously damage biodiversity because it takes away homes of animals. Introduced species because it would transmit certain diseases. Overexploitation would reduce the population of animals and plants. Disruption of interaction networks threatens the animals that are dependent upon this network.
- Human preserving biodiversity would allow more potential ability of species to provide with food and medicine.
Concept Check 55.2
- Because the reduced genetic diversity of small populations make them unable to recover after a natural disaster.
- The small-population approach manages the increases of the genetic diversity within a small population and increase the effective population size. The declining-population approach size is based on only the numbers of male and females that breed.
- The effective population size is smaller than the total population size because not every male and female can breed. Some are impotent, too bad.
Concept Check 55.3
- A small area that supported a lot of endangered species.
- Zoned reserves provide sufficient supplies of forest, water, power, educational opportunity and tourism.
- Habitat corridors increase the rate of movement between habitat patches. It also increases the rate of gen flow between subpopulations. This corridor could also potentially increase the chances of disease spreading.
Concept Check 55.4
- The goal is to restore ecosystems to their natural state, by removing toxic waste, or clean up the ocean trashes, and to stop deforestation and grow new trees.
- Bioremediation uses organisms, like fungi or plants, to detoxify pollutants from ecosystems. Biological augmentation uses nitrogen-fixing plants to add essential material to degraded ecosystems.
Concept Check 55.5
- Sustainable development is the long-term prosperity of human society and ecosystem. The development of skills in management, and conservation of Earth's resources, and preserve the biodiversity.
- Biophilia might influence environmental ethics by acting as a significant motivation for the development of an environmental ethic that resolves not to allow species to become extinct or ecosystem to be destroyed.
- C. the current extinction rate is far higher than the rate at any time in the past 100,000 years
- B. restoration ecology
- D. 20
- D. its genetic diversity is very low
- D. restoration ecology
- E. habitat alteration, fragmentation, and destruction
- B. implement a conservation plan at the outset of a study, as it is too risky to wait until data are gathered and analyzed
- C. introduce new individuals transported from other populations of the same species
- A. about 25% of Earth's land area is now protected
- B. a research agenda to study biodiversity and support sustainable development
The rate should be increasing. If an invasive plant first appears, most bugs won't recognize it as food. A few bugs would have a random genetic mutation to recognize it as food. This way a new source of food just opened up for those bugs. Then the breeding would speed up and more bugs will eat that food. Soon this mutation becomes genetically normal for every individual of the bug species and thus the rate of the attack on an introduced species was increased dramatically from zero to the present rate.
I would construct the road along the forest area so it would be the fastest for the research workers to go to anywhere of the forest and also anywhere of the pastured grassland. I will build the small maintenance building in the forest at 100 meters from the grassland. This way we would be able to maintain the amount of female cowbirds in and out of the forest.