AP Biology Ecology & Population Ecology Flashcards

A set of practice flashcards covering ecology, population dynamics, biogeochemical cycles, ecosystem energy flow, community interactions, and conservation biology based on the provided notes.

What are the four Big Ideas guiding the Ecology Unit?

1) The process of evolution drives the diversity and unity of life; 2) Biological systems use free energy and building blocks to reproduce and to maintain homeostasis; 3) Living systems store, retrieve, transmit and respond to information essential to life processes; 4) Biological systems interact, and these systems and their interactions possess complex properties.

Name the seven life processes and briefly explain each.

1) Made of highly ordered structures called cells; 2) Reproduction; 3) Growth and Development; 4) Respond to the Environment; 5) Energy Processing; 6) Regulation; 7) Evolutionary Adaptation.

What are the 10 levels of biological organization and their definitions?

Molecule (two or more atoms covalently bonded); Organelle (specialized structures within a cell); Cell (basic unit of structure and function); Tissue (group of cells with a function); Organ (group of tissues functioning together); Organ System (group of organs); Population (all individuals of a species in an area); Community (all interacting populations in an area); Ecosystem (living and non-living factors in an area with energy flow and nutrient cycling); Biosphere (global ecosystem or areas of Earth where life exists).

How does evolution account for unity and diversity of life?

Species accumulate genetic differences as they evolve; the more time they evolve independently, the more differences accumulate. Similarities arise from a common ancestry, and all life shares fundamental characteristics (DNA → RNA → protein, the Central Dogma).

How is science a process?

Science is a method to understand the natural world through observations, forming hypotheses, and rigorously testing them to obtain data analyzed statistically; the process is repeatable and subject to modification and revision.

List the steps in hypothesis-based inquiry (Scientific Method).

Observations, inductive reasoning, forming and testing hypotheses with controlled experiments, collecting and analyzing data, interpreting results, publishing and verifying results.

What is ecology and what does it study?

Ecology is the study of interactions between organisms and the environment, including climate’s influence on life zones, species distributions, populations, communities, ecosystems, global ecology, and conservation.

How are Darwin's evolution and ecology related sciences?

Evolutionary theory explains how populations evolve in response to environmental selective pressures; ecology studies those interactions that drive evolution and ecological dynamics.

Differentiate between biotic and abiotic factors and give examples.

Biotic factors are living components (predators, prey, decomposers); Abiotic factors are non-living components (temperature, precipitation, sunlight, wind, soil).

Give an example of how biotic and abiotic factors influence each other.

Temperature and precipitation influence plant distributions; large herbivores affect soil compaction and decomposers nutrient cycling; photosynthesizers fix carbon and release O2.

Define the following terms with examples: Biosphere, Ecosystem, Community, Population.

Biosphere: global ecosystem (Earth). Ecosystem: all living and non-living factors in an area with energy flow and nutrient cycling (e.g., tropical rainforest). Community: all populations in an area and their interactions (e.g., Tyler Park community). Population: all individuals of a species in a defined area (e.g., Tyler Park white-tailed deer population).

How does dispersal influence the distribution of individuals within a population?

Dispersal determines where individuals can settle (e.g., seeds dropped by wind vs seeds dispersed by animals or fruit), shaping geographic distribution.

What factors influence or limit geographic distribution of a population?

Dispersal method, abiotic factors (e.g., temperature, moisture), and biotic factors (predators, food availability, competitors).

Give 4 abiotic factors and how they influence distribution.

1) Temperature – affects physiology and enzyme activity; 2) Water – essential for photosynthesis and life; 3) Oxygen – required for cellular respiration; 4) Salinity – affects osmoregulation.

Define Biome, Photic zone, and Benthic zone.

Biome: major life zones characterized by vegetation/climate (terrestrial) or physical environment (aquatic). Photic zone: surface region with enough light for photosynthesis. Benthic zone: bottom region of a body of water, often low light and high pressure.

What factors are significant to population distribution and abundance in a lake?

Light depth, temperature (thermoclines), nutrient distribution, and oxygen distribution.

Differentiate oligotrophic and eutrophic lakes.

Oligotrophic: nutrient-poor, oxygen-rich; Eutrophic: nutrient-rich, oxygen depleted at depth due to decomposition.

What are the two main abiotic factors that define a land biome?

Temperature and precipitation.

Differentiate density and dispersal.

Density is the number of individuals per unit area; dispersal is the pattern of spacing among individuals (how they are distributed in space).

How can ecologists estimate the numbers in a population?

Using sampling techniques: count small plots and extrapolate, or count indicators (nests, tracks, feces, burrows).

Explain immigration and emigration in population counts.

Immigration and emigration alter densities and can vary inconsistently, making population size difficult to count precisely.

Describe three patterns of dispersal.

Clumped (grouped near resources), Uniform (even spacing due to competition), Random (no pattern; e.g., wind-dispersed seeds).

Define life table, cohort, and survivorship curve.

Life table: survival and reproductive rates by age. Cohort: group of individuals of the same age. Survivorship curve: graph of how many individuals survive to each age class.

Describe the three patterns of survivorship with examples.

Type I: high survival early, then sharply decreasing (humans, elephants). Type II: constant death rate (rodents, lizards). Type III: high early mortality with many surviving later (fish, marine invertebrates).

Write and define the formula for a population's growth under an idealized (exponential) environment.

dN/dt = r_max N (Exponential growth); N is population size, r is intrinsic rate of increase.

What is carrying capacity (K) and what resources may limit it?

Carrying capacity is the maximum population size the environment can sustain indefinitely. Limiting resources include energy, shelter, predators, nutrients, water, nesting sites.

How does a real population growth curve differ from an ideal one?

In the real world, resources limit growth, producing a logistic (S-shaped) curve that levels off at carrying capacity (K) rather than a continuous J-curve.

What happens to population growth as it approaches carrying capacity?

Growth rate slows and approaches zero as N approaches K; eventually the population stabilizes around K.

Differentiate density-independent vs density-dependent factors with examples.

Density-independent: birth/death rates not affected by population density (natural disasters, droughts, heat waves). Density-dependent: rates influenced by population density (food, water, sunlight, nutrients, disease, territoriality).

Identify factors that regulate population size with examples.

Competition for resources (plants vs light; animals for food), Disease (transmission increases with density), Territoriality (limited space), Intrinsic factors (hormonal/behavioral factors).

How can age structure diagrams reflect social conditions?

Young-skewed populations (e.g., Afghanistan) imply high future demand for education and jobs; aging populations (e.g., US/Italy) imply increased needs for elder care and retirement systems.

Define community and give an example.

Community: all of the interacting populations of different species in an area. Example: Tyler State Park community.

Fill in the chart of interspecific interactions: what are the effects on population density for Competition, Predation, Parasitism, Mutualism, and Commensalism?

Competition: -/- (densities decrease for both). Predation: +/− (predator increase, prey decrease). Parasitism: +/− (parasite increases, host decreases). Mutualism: +/+ (both increase). Commensalism: +/0 (one benefits, other unaffected).

What is the competitive exclusion principle?

Two species competing for the same limiting resource cannot coexist in the same niche; one will outcompete the other and exclude it.

Define ecological niche.

The role a species plays in the community, including the resources it uses and how it influences the environment (biotic and abiotic factors).

How do identical niches get resolved to allow coexistence?

Resource partitioning: niche differentiation where species use different resources or use them at different times or places, leading to coexistence (fundamental vs realized niche).

List predator adaptations that enable success.

Senses, speed, camouflage, venom, fangs, etc.

List prey adaptations to avoid capture.

Behavioral (hiding, fleeing, self-defense, herding), morphological (camouflage, coloration), physiological (poisonous or unpalatable chemicals).

Define cryptic coloration and give an example.

Cryptic coloration is camouflage that enables concealment; example: walking stick insect.

Define aposematic coloration and give an example.

Aposematic coloration is warning coloration signaling danger or unpalatability; example: poison dart frogs.

Define Batesian mimicry and give an example.

Harmless species mimics harmful/unpalatable species (e.g., Viceroy mimicking Monarch).

Define Mullerian mimicry and give an example.

Two or more harmful/unpalatable species resemble each other to reinforce avoidance (e.g., yellow and black warning patterns in multiple stinging insects).

Differentiate species diversity, species richness, and species abundance.

Richness: number of different species; Abundance: proportion of the population that each species represents; Diversity: combines richness and evenness across species.

Define trophic structure, food chain, and food web.

Trophic structure: feeding relationships in a community. Food chain: transfer of energy from autotrophs to herbivores to carnivores to decomposers. Food web: interconnected set of food chains in a community.

What limits the length of a food chain and why?

Typically two to three trophic levels; energy transfer between levels is about 10% efficient, with about 90% lost as heat, limiting chain length.

Define keystone species and explain why they matter.

A species that has a disproportionately large influence on its community, often maintaining biodiversity and ecosystem structure (e.g., sea otter maintaining kelp forests by controlling urchin populations).

What is ecological succession and what are primary vs secondary succession?

Succession is the sequential colonization of an ecosystem by producers and consumers leading to a mature ecosystem. Primary succession starts with no soil (e.g., volcanic eruption); secondary succession starts with soil present (e.g., after a forest fire).

How does the definition of ecosystems expand on the concept of the community?

Ecosystems include not only the living (biotic) interactions but also the abiotic components and energy/nutrient flows linking organisms to their physical environment.

Explain the conservation of energy in an ecosystem.

A fixed amount of energy enters an ecosystem; energy is transformed and transformed again, with much of it lost as heat at each transfer, determining how much life can be sustained.

How does energy flow differ from nutrient cycling in ecosystems?

Energy flows through an ecosystem from sun to producers to consumers to decomposers and is lost as heat at each transfer; nutrients cycle within the system (water, C, N, P) and are reused.

Identify the trophic levels within an ecosystem.

Primary producers (autotrophs), Primary consumers (herbivores), Secondary and tertiary consumers (carnivores), Decomposers/detritivores.

Define primary productivity, gross primary productivity (GPP), and net primary productivity (NPP).

Primary productivity is the input of energy into organic molecules by producers. GPP is the total primary production by autotrophs. NPP = GPP − autotrophic respiration (Ra); the rate at which biomass accumulates.

State the formula for net primary productivity with its components.

NPP = GPP − Ra (or NPP = GPP − autotrophic respiration). Units: Joules per square meter per year (J m^-2 yr^-1).

Which ecosystems have the highest net primary productivity per unit area and why?

Tropical rainforests have the highest NPP due to warm temperatures and high rainfall, which support rapid plant growth and nutrient recycling.

Identify the limiting factors in aquatic ecosystems.

Light and nutrients limit photosynthesis and primary productivity in aquatic systems.

Define eutrophication and its impact on lake communities.

Eutrophication is the enrichment of nutrients leading to algal blooms; as they die and decompose, oxygen is depleted, causing hypoxic or dead zones and reduced biodiversity.

Why is open ocean productivity low?

Photic zone is thin, and essential nutrients like nitrogen and phosphorus are scarce in the deep open ocean.

Define secondary productivity.

Secondary productivity is the rate at which biomass is produced by heterotrophic consumers from consumed food.

How does energy change between trophic levels?

Energy decreases at each transfer; roughly 10% is transferred to the next level, while ~90% is lost as heat.

Identify essential elements that move through biogeochemical cycles in ecosystems.

Carbon, Oxygen, Sulfur, Nitrogen, Phosphorus, Potassium, Calcium (and others) move through cycles.

Describe the major processes moving carbon through the ecosystem.

Photosynthesis, Cellular respiration, Decomposition, Burning of fossil fuels, volcanic activity; carbon reservoirs include atmosphere, oceans, soils, biomass, fossil fuels.

What act as carbon reservoirs?

Fossil fuels, soils and sediments, oceans, atmosphere, and biomass.

What activities increase atmospheric CO2?

Cellular respiration, combustion of fossil fuels, and volcanic activity.

Outline the phosphorus cycle.

Weathering of rocks releases phosphates; run-off carries phosphates; uptake by organisms (assimilation); decomposition returns phosphates to soil; phosphates can precipitate as minerals.

Outline the nitrogen cycle and define nitrogen fixation, ammonification, nitrification, denitrification, and assimilation.

Nitrogen fixation: converting atmospheric N2 to ammonia (NH3)/nitrates (NO3−); Ammonification: conversion of organic N to NH4+; Nitrification: NH4+ to NO2− to NO3−; Denitrification: NO3− to atmospheric N2; Assimilation: incorporation of inorganic N into organic compounds.

Fill in the nitrogen cycle diagram conceptually.

Atmospheric N2 → Nitrogen fixation (bacteria) → NH4+/NO3− (nitrification/ammonification) → Plants/Animals incorporate N → Decomposition releases N → Denitrification returns N2 to atmosphere.

Why is human population growth central to most environmental issues?

Growing population size and consumption expand environmental footprint, driving resource depletion, habitat destruction, pollution, water use, and climate impacts.

Identify causes and effects of acid precipitation (acid rain).

Caused by sulfur and nitrogen oxides from burning fossil fuels; lowers pH of rain, soils, and surface waters, harming trees and aquatic life and altering nutrient availability.

Define biological magnification and give an example.

The accumulation of toxins in higher trophic levels of a food web; example: PCBs accumulating in Great Lakes herring gulls.

What factors contribute to global warming?

Greenhouse gases (CO2, CH4, N2O, fluorinated gases) trap heat in the atmosphere; greenhouse effect; ozone dynamics and changes in atmospheric circulation can also influence warming.

Differentiate conservation and restoration ecology.

Conservation ecology aims to preserve biodiversity and ecosystem processes to prevent extinctions; Restoration ecology aims to restore degraded or destroyed ecosystems to a healthier state.

Why is biodiversity vital to human welfare?

Provides medicines, food, fibers; ecosystem services like purifying air and water, detoxifying waste, pollination, soil formation and nutrient cycling, cultural and recreational value.

List the four major threats to biodiversity and give examples.

Habitat loss/fragmentation; Introduced (non-native) species; Overharvesting; Global change (climate, ocean chemistry).

Explain the small population approach and the extinction vortex.

Small populations are more prone to inbreeding and genetic drift, reducing genetic variability and fitness, creating a cycle that leads toward extinction.

Describe the basic steps common in the declining-population approach.

Study processes that shrink populations and identify environmental factors causing declines (e.g., deforestation, reduced food supply) to guide conservation actions.

Define biodiversity hotspots and explain their importance.

Regions with a high density of endangered and endemic species in a small area; conservation priority due to high biodiversity and vulnerability.

Describe bioremediation and give an example.

Use of natural organisms to clean up polluted environments; example: oil-degrading bacteria breaking down hydrocarbons.

Describe sustainable development.

Economic development that meets the needs of the present without compromising the ability of future generations to meet their own needs.