Animal Behavior, Ecology, and Ecosystem Dynamics: Key Concepts and Models

What is animal behavior?

All the ways animals interact with other members of their species, other species, and their environment.

What is the difference between innate and learned behavior?

Innate behavior is genetically hardwired and inherited, while learned behavior develops over an organism's lifetime.

What are the types of learned behaviors?

Habituation, classical conditioning, operant conditioning, and observational learning.

What is imprinting in animal behavior?

A period in early life when certain behaviors are learned and become fixed.

What is migration in the context of animal behavior?

Long distance seasonal movement for better climate.

What is a circadian rhythm?

A 24-hour biological clock that regulates physiological processes.

What are the four basic questions proposed by Tinbergen regarding behavior?

Causation, development, function/adaptive value, and phylogeny.

What is homeostasis?

The process of maintaining an organism's stable internal environment.

What are the four interacting components required for homeostasis?

Stimulus, sensor, control, and effector.

What is the difference between positive and negative feedback loops?

Positive feedback loops intensify or exaggerate the stimulus (e.g., childbirth), while negative feedback loops bring a variable back to normal (e.g., thermoregulation).

What are biotic and abiotic factors?

Biotic factors are living components of an ecosystem, while abiotic factors are nonliving components.

What are the types of biomes mentioned?

Tundra, taiga, temperate forest, grassland, desert, savannah, tropical rainforest, marine, and ice.

What influences population density?

Population density is affected by births, deaths, immigration, and emigration.

What are the three patterns of dispersion in populations?

Clumped, uniform, and random distributions.

How do life tables and survivorship curves relate to population ecology?

They summarize specific trends in demographics, reflecting population dynamics.

How can ecologists estimate birth and death rates in gray whales?

By counting the number of young born each year for birth rates and observing changes in adult numbers for death rates.

What does the exponential model describe?

Population growth in an idealized, unlimited environment.

How is a population's per capita growth rate calculated in the exponential model?

It equals the birth rate minus the death rate.

What is the exponential growth equation?

𝑑𝑁/𝑑𝑡=𝑟𝑁, where 𝑟 is the intrinsic rate of increase and 𝑁 is the population size.

What happens to populations under the exponential model over time?

Both populations will continue to grow to infinite size, regardless of the specific value of r.

What does the logistic model describe?

How a population grows more slowly as it nears its carrying capacity.

Why can't exponential growth be sustained in any population?

Because it does not incorporate carrying capacity (𝐾), the maximum population size the environment can support.

What is the logistic growth equation?

𝑑𝑁/𝑑𝑡=𝑟𝑁𝐾-𝑁/𝐾, which shows growth levels off as population size approaches carrying capacity.

What are some methods to increase the carrying capacity of a species in a wildlife preserve?

Increasing food supply, protecting from predators, and providing more nesting or reproduction sites.

What are life history traits?

Evolutionary outcomes reflected in the development, physiology, and behavior of organisms.

What is the difference between big-bang and iteroparous organisms?

Big-bang organisms reproduce once and die, while iteroparous organisms produce offspring repeatedly.

What do life history traits such as brood size and age at maturity represent?

Trade-offs between conflicting demands for time, energy, and nutrients.

What is r-selection?

A life history strategy characterized by rapid reproduction and low survival rate.

What is K-selection?

A life history strategy characterized by producing fewer high-quality offspring and investing in their survival.

Why are ecological trade-offs common?

Because organisms do not have access to unlimited energy and resources, using them for one function can decrease availability for others.

What are density-dependent factors?

Factors that regulate population growth where death rates rise and birth rates fall with increasing density.

What is the difference between density-dependent and density-independent factors?

Density-dependent factors vary with population density, while density-independent factors do not.

How do density-dependent changes in birth and death rates affect population growth?

They curb population increase through negative feedback and can stabilize a population near its carrying capacity.

What is carrying capacity (𝐾)?

The maximum population size that the environment can support.

What is the significance of the logistic model in ecology?

It provides a more realistic understanding of population growth by incorporating environmental limits.

How does the logistic model fit real populations?

It fits few real populations perfectly but is useful for estimating possible growth.

What is the role of natural selection in life history traits?

Natural selection shapes life history traits as organisms adapt to their environments.

What is a trade-off in ecological terms?

A situation where the allocation of resources to one function reduces the resources available for another function.

What are density-dependent limiting factors?

Intraspecific competition for food or space, increased predation, disease, and intrinsic physiological factors.

How do environmental conditions affect population size?

Changing environmental conditions periodically disrupt populations, leading to size fluctuations.

What trend has the global human population exhibited since 1650?

The global human population has grown exponentially.

What has happened to the rate of human population growth in the last 60 years?

The rate of growth has fallen by more than half.

What factors contribute to differences in population growth among nations?

Differences in age structure, infant mortality rates, and life expectancy at birth.

What is an ecological footprint?

The aggregate land and water area needed to produce resources consumed and absorb waste.

How does the ecological footprint relate to Earth's carrying capacity?

It measures how close we are to the carrying capacity, which is uncertain.

What unique ability do humans have regarding carrying capacity?

Humans can reduce global population through contraception and family planning.

What are the three broad categories of interspecific interactions?

Competition, exploitation, and positive interactions.

What does competitive exclusion state?

Two species competing for the same resource cannot coexist permanently in the same place.

What is resource partitioning?

The differentiation of ecological niches that enables species to coexist in a community.

Provide an example of competition between species.

A fox and a bobcat competing for prey.

Provide an example of predation between species.

An orca eating a sea otter.

Provide an example of herbivory between species.

A bison eating grass.

Provide an example of parasitism between species.

A parasitoid wasp that lays its eggs on a caterpillar.

Provide an example of mutualism between species.

A fungus and an alga that make up a lichen.

Provide an example of commensalism between species.

A wildflower that grows in a maple forest and a maple tree.

What affects species diversity in a community?

The number of species (species richness) and their relative abundance.

How do more diverse communities compare to less diverse ones?

More diverse communities produce more biomass, show less year-to-year variation in growth, and are more resistant to introduced species.

What is trophic structure?

A key factor in community dynamics that links trophic levels from producers to top carnivores.

What are foundation and keystone species?

Foundation species are large or abundant members providing food or habitat; keystone species are less abundant but exert a disproportionate influence on community structure.

What role do ecosystem engineers play in community structure?

Ecosystem engineers influence community structure through their effects on the physical environment.

What does the intermediate disturbance hypothesis suggest about species diversity?

Moderate levels of disturbance can foster higher species diversity than low or high levels of disturbance.

What is ecological succession?

Ecological succession is the sequence of community and ecosystem changes after a disturbance.

What is the difference between primary and secondary succession?

Primary succession occurs in an area that is virtually lifeless, while secondary succession occurs after a disturbance that removes most but not all organisms.

How does species richness vary with latitude?

Species richness generally declines along a latitudinal gradient from the tropics to the poles.

What factors influence the diversity gradient in ecosystems?

Climate influences the diversity gradient through energy (heat and light) and water, and the greater age of tropical environments may contribute to their higher species richness.

What is the species-area curve?

The species-area curve formalizes the principle that species richness is directly related to a community's geographic size.

What does the island equilibrium model state?

The island equilibrium model states that species richness on an ecological island reaches an equilibrium where new immigrations are balanced by extinctions.

How have glaciations influenced latitudinal patterns of diversity?

Glaciations can completely destroy communities in temperate and polar regions, leading to tropical communities being older and having higher species diversity due to more time for speciation.

What is the role of pathogens in community structure?

Pathogens play a key role in structuring terrestrial and marine communities.

What are zoonotic pathogens?

Zoonotic pathogens are transferred from other animals to humans and cause most emerging human diseases.

What is a keystone species?

A keystone species is one with a pivotal ecological role in its community.

How can a pathogen affecting a keystone species alter community structure?

A pathogen that harms a keystone species could greatly alter community structure, potentially leading to drastic changes in species diversity.

What constitutes an ecosystem?

An ecosystem consists of all the organisms in a community and all the abiotic factors with which they interact.

How does energy flow through ecosystems?

Energy is conserved but released as heat during ecosystem processes, flowing through ecosystems rather than being recycled.

What governs chemical cycling in ecosystems?

Chemical elements enter and leave an ecosystem and cycle within it, subject to the law of conservation of mass.

How do inputs and outputs of elements affect ecosystems?

Inputs and outputs are generally small compared to recycled amounts, but their balance determines whether the ecosystem gains or loses an element over time.

According to the second law of thermodynamics, how does the biomass of primary producers compare to that of consumers?

The typical biomass of primary producers in an ecosystem is expected to be greater than that of consumers.

What is the primary reason energy flows through ecosystems rather than being recycled?

Energy flows through ecosystems because it is lost as heat during energy conversions, following the second law of thermodynamics.

What is the difference between gross primary production (GPP) and net primary production (NPP)?

GPP is the total energy assimilated by an ecosystem, while NPP is the energy accumulated in autotroph biomass, calculated as GPP minus the energy used by primary producers for respiration.

What additional variable is needed to estimate net ecosystem production (NEP) if net primary production (NPP) is known?

To estimate NEP, you need to know the total respiration (RT) contributions from both heterotrophs and autotrophs.

Why might measuring the respiration of primary producers and other organisms in ocean water be difficult?

In ocean water, primary producers and other organisms are usually mixed together, making it hard to separate their respective respirations.

What is the typical trophic efficiency of energy transfer between trophic levels?

Trophic efficiency is typically around 10%.

How does production efficiency change for runners during a long-distance race compared to when they are sedentary?

Runners have lower production efficiency during a race because they use much more energy in respiration compared to when they are sedentary.

What drives the global water cycle?

The global water cycle is driven by solar energy.

How does the carbon cycle primarily function in ecosystems?

The carbon cycle reflects the reciprocal processes of photosynthesis and cellular respiration.

What role do prokaryotes play in the nitrogen cycle?

Prokaryotes contribute to the nitrogen cycle by fixing nitrogen from the atmosphere into forms usable by ecosystems.

What effect does logging have on water runoff and mineral loss in ecosystems, according to the Hubbard Brook case study?

Logging increases water runoff and can cause significant losses of minerals from ecosystems.

Why is decomposition in hot deserts relatively slow despite higher temperatures?

Decomposition is slow in hot deserts due to factors other than temperature, such as a shortage of water and nutrients.

What is bioremediation in the context of restoration ecology?

Bioremediation is the process of using organisms to detoxify polluted ecosystems.

What is biological augmentation?

Biological augmentation involves using organisms to add essential materials to ecosystems.

Why do engineers separate topsoil from deeper soil when preparing a site for surface mining?

Separating topsoil from deeper soil allows engineers to return the deeper soil first and then apply the more fertile topsoil to enhance revegetation success.

What is the Simpson Index used for in ecology?

The Simpson Index is used to measure biodiversity by considering the number of species and their relative abundance.

What does 'n' represent in the Simpson Index formula?

In the Simpson Index formula, 'n' represents the total number of organisms of a particular species.

What is the Lincoln Index used for in ecology?

The Lincoln Index is a method for estimating the population size of a closed population using a mark and recapture method.

What is the formula for the Lincoln Index?

The Lincoln Index formula is L = (n1 × n2) / n3, where n1 is the number of marked individuals, n2 is the total number captured in the second sample, and n3 is the number of marked individuals recaptured.

How do limiting factors affect primary production in aquatic ecosystems?

In aquatic ecosystems, light and nutrients are the primary limiting factors for primary production.

What climatic factors influence primary production in terrestrial ecosystems?

In terrestrial ecosystems, climatic factors such as temperature and moisture affect primary production at large scales.

What is net ecosystem production (NEP)?

NEP is the total biomass accumulation of an ecosystem, defined as the difference between gross primary production and total ecosystem respiration.

What is the significance of understanding energy transfer efficiency in ecosystems?

Understanding energy transfer efficiency helps explain the structure of food webs and the biomass available at different trophic levels.