Ecology and Evolutionary Biology - Exam 2 Study Guide

Comprehensive vocabulary flashcard set covering organismal, population, community, and ecosystem ecology based on the Exam 2 study guide.

Endotherm

An organism that generates its own body heat primarily through internal metabolic processes.

Ectotherm

An organism that relies on external environmental heat sources to regulate its body temperature.

Homeotherm

An organism that maintains a relatively constant body temperature.

Poikilotherm

An organism that allows its body temperature to fluctuate with the ambient environment.

Stenothermal

An organism capable of tolerating only a narrow range of ambient temperatures.

Eurythermal

An organism capable of tolerating a wide range of ambient temperatures.

Heat death / incapacitation

Physiological damage caused by protein denaturation, enzyme inactivation, and the disruption of cell membrane fluidity.

Bergmann’s Rule

Ecological principle stating that populations of larger body sizes are found in colder environments, while populations of smaller body sizes are found in warmer environments.

Allen’s Rule

Ecological principle stating that endotherms adapted to cold climates tend to have shorter limbs and appendages than equivalent animals adapted to warm climates, minimizing surface area for heat loss.

Phenotypic plasticity

The ability of an organism to alter its phenotype in response to environmental conditions.

Acclimatization

A reversible phenotypic change induced by seasonal and/or geographic changes.

Hardening response

An abrupt (minutes to hours) phenotypic change involving heat shock proteins resulting from exposure to stressful conditions.

Shivering thermogenesis

The generation of body heat through involuntary muscle contractions.

Non-shivering thermogenesis

The production of heat without muscular work, utilizing brown adipose tissue and uncoupling proteins.

Torpor

A short-term reduction of body temperature and metabolic rate.

Hibernation

A prolonged, deep metabolic depression lasting weeks or months that reduces metabolic energy flow when food resources are scarce.

Periodic rewarming

Periodic arousals during hibernation that allow animals to clear waste, restore immune function, and fulfill sleep requirements.

Freeze tolerance

A cold-hardiness strategy that permits controlled ice formation in extracellular spaces while preventing intracellular freezing.

Freeze intolerance

A cold-hardiness strategy that relies on deep supercooling and antifreeze proteins to prevent bodily fluids from freezing.

Supercooling

A state in which body fluids remain liquid below $0^{\circ}\text{C}$ in the absence of ice nucleation sites.

Brumation

The reptilian form of hibernation during cold weather.

Wood frog freeze tolerance

An adaptation where high levels of glucose and urea accumulate as cryoprotectants, allowing up to $65\%$ of total body water to freeze solid.

Antifreeze proteins

Specialized proteins found in fish that bind to small ice crystals to inhibit their growth in sub-zero marine waters.

Ecology

The scientific study of interactions between organisms and their environment.

Population ecology

The branch of ecology that focuses on population size, dynamics, and environmental interactions.

Demography

The study of vital statistics of a population and how they change over time, especially birth and death rates.

Cohort life table

A life table that follows a specific group of individuals from birth to death; considered the most informative type.

Static life table

A life table providing a snapshot of population survival across age classes; considered the most easily obtained type.

Type I survivorship curve

A survivorship curve characterized by high survival rates during early and middle life, followed by a sharp drop in old age.

Type II survivorship curve

A survivorship curve characterized by a constant mortality rate throughout an organism's lifespan.

Type III survivorship curve

A survivorship curve characterized by high mortality in early life and high survivorship among adults.

Life history traits

Biological and physiological characteristics of a species that govern its schedule of growth, development, reproduction, and survival.

r-selected species

Species adapted to unstable environments, characterized by high growth rates, production of many small offspring, and minimal parental care.

K-selected species

Species adapted to stable environments near carrying capacity, characterized by few large offspring and high parental investment.

Semelparity

A reproductive pattern where an organism undergoes a single reproductive event during its lifetime.

Iteroparity

A reproductive pattern where an organism undergoes repeated reproductive events throughout its lifetime.

Exponential population growth model

A model represented by $\frac{dN}{dt} = r_{\max}N$ or $\frac{dN}{dt} = rN$, where populations with a higher per capita rate of increase grow more quickly.

Carrying capacity ($K$)

The maximum population size that a particular environment can sustain.

Logistic population growth model

A model represented by $\frac{dN}{dt} = rN\left(\frac{K - N}{K}\right)$, which incorporates carrying capacity ($K$) to modify the per capita rate of increase as population size changes.

Density-dependent factors

Factors that cause the population growth rate to decrease as the population approaches carrying capacity ($K$).

Density-independent factors

Factors that limit a population's growth identically regardless of density, providing no negative feedback.

Ecological community

Populations of different species living close enough together for potential interaction.

Ecological niche

The sum of a species' use of the biotic and abiotic resources in its environment, defined as its ecological role or an n-dimensional hypervolume.

Realized niche

The actual environmental space occupied by an organism within its community.

Fundamental niche

The total environmental space that an organism could possibly occupy in the absence of limiting interactions.

Allopatric populations

Populations that are geographically separated from one another.

Sympatric populations

Populations that are geographically overlapping.

Trophic structure

The feeding relationships between organisms in a community, consisting of food chains that form food webs.

Energetic hypothesis

The premise that food chain length is limited by an efficiency of energy transfer of roughly $10\%$ between trophic levels, explaining the reduced biomass of top predators.

Keystone species

A species that exerts an inordinate influence on community structure relative to its abundance (e.g., krill in polar marine ecosystems).

Disturbance

An event such as a storm, fire, flood, or human activity that changes a community by removing organisms or altering resource availability.

Ecological succession

The transition in species composition of a community over time.

Primary succession

Ecological succession occurring in an area where organisms were not previously present and where soil had not yet formed.

Secondary succession

Ecological succession occurring when an existing community has been cleared by a disturbance that leaves the soil intact.

Ecosystem

A biological community plus all the physical (abiotic) factors with which it interacts.

Gross primary productivity (GPP)

The total amount of primary production created within an ecosystem.

Net primary productivity (NPP)

The gross primary productivity minus the energy used in autotrophic respiration ($\text{GPP} - \text{respiration}$), reaching its highest levels in tropical rainforests, coral reefs, and estuaries.

Oligotrophic lakes

Lakes that are nutrient-poor and oxygen-rich.

Eutrophic lakes

Lakes that are nutrient-rich and oxygen-poor.

Eutrophication

The process by which a body of water becomes overly enriched with minerals and nutrients, causing excessive growth of plants and algae.

Acid rain

Precipitation in wet or dry forms with an acidic pH of approximately $4.3$, compared to normal precipitation with a pH of approximately $5.6$.

Methemoglobinemia

A health condition caused by nitrate pollution in well water, where stomach bacteria convert nitrates into nitrites that transform hemoglobin into methemoglobin, reducing oxygen-carrying capacity.

Bioaccumulation

The progressive build-up of a contaminant concentration within an individual organism.

Biomagnification

The progressive increase in the concentration of a contaminant at successively higher levels of the food chain.