AP Biology Ecology & Population Ecology Flashcards

Big Ideas in Ecology

Four Big Ideas to keep in mind as you study Ecology units:
- The process of evolution drives the diversity and unity of life.
- Biological systems utilize free energy and molecular building blocks to reproduce and to maintain homeostasis.
- Living systems store, retrieve, transmit, and respond to information essential to life processes.
- Biological systems interact, and these systems and their interactions possess complex properties.
This set of notes is designed to cover the chapters and concepts linked to the Ecology Unit as outlined in the transcript. Use them alongside labs, review books, and chapter reviews to prepare for assessments.

Chapter 1: Exploring Life (Campbell) & Chapter 1: Introduction (Urry)

1) The 7 life processes (definitions and brief explanations)

Made of highly ordered structures called cells
Reproduction — organisms produce new individuals of their kind
Growth and Development — DNA controls growth and form
Respond to the Environment — organisms respond to stimuli
Energy Processing — organisms take in, convert, and use energy
Regulation — organisms maintain homeostasis
Evolutionary Adaptation — populations evolve to adapt to their environments

2) The 10 levels of biological organization (define each)

Molecule — two or more atoms covalently bonded
Organelle — specialized structures with specific functions within a cell
Cell — basic unit of structure and function in living things
Tissue — group of cells working together for a common function
Organ / Organ system — group of tissues and organs functioning together
Organism — a living individual organism
Population — all individuals of a species in an area
Community — all the interacting populations in an area
Ecosystem — all living (biotic) and nonliving (abiotic) components in an area
Biosphere — the global sum of all ecosystems; the zones of Earth where life exists

3) The 3 domains and examples

Bacteria — unicellular prokaryotes (e.g., E. coli)
Archaea — unicellular prokaryotes; often extremophiles (e.g., methanogens, halophiles, thermophiles)
Eukarya — eukaryotes with membrane-bound organelles (Plants, Animals, Fungi, Protists)

4) How evolution accounts for unity and diversity

Species accumulate genetic differences as they evolve; as lineages diverge, they accumulate differences (diversity).
Yet, all life shares fundamental characteristics (e.g., DNA → RNA → protein; central dogma), reflecting unity of life from common ancestry.

5) The nature of science as a process

Science is an approach to understanding the natural world through observations, hypotheses, and rigorous testing.
Data are analyzed statistically; the process must be repeatable and is continually revised based on evidence.

6) Steps in hypothesis-based inquiry (the Scientific Method)

Observations → inductive reasoning → form hypotheses → conduct controlled experiments → collect and analyze data → interpret results → publish and verify results

Chapter 50/52: Ecology & Population Ecology (Campbell/Urry)

1) Ecology: field of study

Interactions between organisms and their environment
Climate influences life zones on land and in oceans; affects species distributions, population sizes, communities, ecosystems
Encompasses global ecology and conservation

2) Darwin’s theory & ecology relation

Evolutionary theory: populations evolve in response to selective pressures in the environment (biotic and abiotic factors)
Ecology studies these interactions and pressures; together they describe how populations adapt and change

3) Biotic vs. abiotic factors (definitions & examples)

Abiotic: non-living chemical/physical features (temperature, precipitation, sunlight, wind, soil)
Biotic: living organisms (predators, prey, decomposers, parasites, etc.)

4) Interaction examples between biotic and abiotic factors

Temperature and precipitation influence plant distributions; large herbivores compact soil, affecting decomposers and nutrient cycling
Photosynthesizers fix carbon and release O2; their activity is influenced by abiotic factors like light and temperature

5) Key terms and examples

Biosphere — global ecosystem; the part of Earth where life exists
Ecosystem — all living and nonliving components in an area; energy flow and nutrient cycling among organisms and their environment (example: tropical rainforest ecosystem)
Community — all populations in an area and their interactions (example: Tyler Park community)
Population — all individuals of a species in an area; size & dynamics (example: Tyler Park white-tailed deer population)

6) Dispersal and distribution

Dispersal influences where individuals occur by moving away from origin (seed dispersal vs. animal movement, wind-dispersed seeds, etc.)

7) Factors shaping geographic distribution (figure 50.6 considerations)

Dispersal method, abiotic factors, biotic factors (predators, food sources, competitors, etc.)

8) Four abiotic factors and their influence on distribution

Temperature — affects cellular processes and organism physiology
Water — essential for photosynthesis and all life; major component of organisms
Oxygen — required for cellular respiration to generate ATP
Salinity — affects osmoregulation and water balance

9) Biome, photic zone, benthic zone (definitions & examples)

Biome — major life zones characterized by vegetation type (terrestrial) or physical environment (aquatic), influenced by energy input, climate, soils, salinity, nutrients, etc.
Photic zone — surface layer of water with sufficient light for photosynthesis (base of food web)
Benthic zone — bottom region of a body of water; low light and high pressure

10) Factors affecting population distribution in lakes

Light penetration, temperature (thermoclines), nutrient distribution, and oxygen distribution

11) Oligotrophic vs. eutrophic lakes

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

12) Abiotic factors defining land biomes

Temperature and precipitation

Chapter 52: Population Ecology (Campbell/Urry)

1) Density vs. dispersal (dispersion)

Density: number of individuals per unit area or volume
Dispersion (dispersion pattern): spacing of individuals within the area

2) Estimating population sizes

Sampling techniques: count small plots and extrapolate
Use indicators (nests, burrows, tracks, feces) to estimate population size

3) Immigration and emigration effects on counts

Movement into/out of populations changes measured densities and can produce irregular counts

4) Three patterns of dispersal (dispersion)

Clumped: individuals grouped near resources
Uniform: even spacing (often due to competition or territoriality)
Random: no predictable pattern (e.g., wind dispersal)

5) Life table, cohort, survivorship curve (definitions)

Life table: survival and reproductive rates by age class
Cohort: group of individuals of the same age in a population
Survivorship curve: plots of the number of individuals that survive to each age class

6) Three patterns of survivorship (types) with examples

Type I: high juvenile survival; mortality increases with age (e.g., humans, elephants)
Type II: relatively constant mortality throughout life (e.g., rodents, lizards)
Type III: high juvenile mortality; survivors live long (e.g., many fishes, marine invertebrates)

7) Population growth under ideal conditions (exponential growth)

Exponential growth model:
- rac{dN}{dt} = rN
- Solution: N(t) = N_0 e^{rt}
r = intrinsic rate of increase; N = population size

8) Carrying capacity (K) and limiting resources

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

9) Real vs. ideal growth curves

Real populations face limited resources and competition
Growth levels off at carrying capacity, producing an S-shaped (sigmoidal) curve: logistic growth

10) Population approaching carrying capacity implications

Growth rate slows and eventually becomes zero as N approaches K
Equation at right: dN/dt = rmax N - (rmax N^2)/K; or commonly written as dN/dt = rN(1 - N/K)

11) Density-dependent vs. density-independent factors

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

12) Factors regulating population size (examples)

Competition for resources
Disease (e.g., transmission is higher when populations are dense)
Territoriality (limits space and population size)
Intrinsic factors (hormones, aggressive interactions)
Age structure and demographic differences among regions/countries

13) Age structure diagrams and global differences

Afghanistan: young population; employment and education challenges
United States/Italy: aging populations; implications for jobs, retirement, and healthcare

Chapter 53: Community Ecology (Campbell) & Chapter 41 (Urry)

1) Define a community

All of the interacting populations of different species in an area (example: Tyler State Park community)

2) Interspecific interactions (table of (+/+, +/-, etc.))

Competition: between species for shared resources; often negative for both (-/-)
Predation: predator–prey interactions; predator benefits (+), prey harmed (-)
Parasitism: parasite benefits; host harmed (+/-)
Mutualism: both species benefit (+/+)
Commensalism: one benefits; the other perceived as unaffected (+/0)

3) Competitive exclusion principle (Gauss’s Paramecium experiment)

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

4) Ecological niche

The role a species plays in the community, including the set of biotic and abiotic resources it uses and the effects it has on others

5) Coexistence via niche differentiation (resource partitioning)

Species occupying identical niches resolve competition by differentiating niches (e.g., different times of activity or feeding sites)
Fundamental vs realized niches

6) Predator adaptations for successful predation

Senses, speed, camouflage, venom, law of the predator's prey, fangs

7) Prey adaptations to avoid predation

Behavioral (hiding, fleeing, self-defense, schooling/herding)
Morphological (camouflage, protective coloration)
Physiological (poisonous, unpalatable)

8) Animal defenses (definitions & examples)

Cryptic coloration (camouflage) — example: walking stick
Cryptic coloration (coloration) — example: poison dart frogs
Aposematic coloration — warning coloration (e.g., vivid colors in poisonous species)
Batesian mimicry — harmless species mimics harmful/unpalatable species (e.g., monarch vs. viceroy; monarch is unpalatable; viceroy mimics monarch)
Mullerian mimicry — two or more harmful species resemble each other (e.g., wasps, bees, stinging insects)

9) Species diversity, richness, and abundance

Richness: number of different species present
Abundance: relative proportion of each species within the community
Diversity = Richness + evenness (not explicitly defined in the transcript, but implied by the terms above)

10) Trophic structure, food chains, and food webs

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

11) Limiting length of a food chain

Roughly two trophic levels can be sustained by energy transfer; energy transfer between levels is ~10% efficient, with ~90% lost as heat at each step
Energy pyramid concept: energy decreases as you move up the trophic levels

12) Keystone species

A species that exerts a disproportionately large influence on a community relative to its abundance; often maintains biodiversity
Example: sea otters in kelp forest ecosystems (prey regulation) or other keystone species in various ecosystems

13) Ecological disturbances and succession

Ecological disturbances: natural or human-caused events that alter communities
Primary succession: begins with no soil (e.g., after volcanic eruption or glacial retreat) — pioneer organisms (lichens, moss) build soil
Secondary succession: soil remains after disturbance (e.g., after forest fire) — faster recovery due to existing soil seed banks and nutrients

Chapter 54: Ecosystems (Campbell) & Chapter 42 (Urry)

1) Ecosystems vs communities

Ecosystems expand the concept of a community by including abiotic interactions with the environment (energy flow and nutrient cycling)

2) Conservation of energy in ecosystems

Energy input is fixed (primarily from the sun); energy flows through the system with losses at each transfer, limiting the amount of life that can be supported

3) Energy flow vs nutrient cycling

Energy flow: Sun → autotrophs → heterotrophs → decomposers; ~90% lost as heat at each transfer
Nutrients cycle through ecosystems (H2O, C, N, P); fixed amount is reused continually as it moves through organisms and the environment

4) Trophic levels within an ecosystem

Primary producers (autotrophs): photosynthesizers and chemosynthesizers
Primary consumers: herbivores
Secondary & tertiary consumers: carnivores
Decomposers/Detritivores: feed on detritus and are fed upon by others

5) Energy budget terms

Primary productivity: amount of energy (usually light) converted into chemical energy by autotrophs per unit area per unit time
Gross primary productivity (GPP): total primary production of autotrophs (energy fixed per area per time)
Net primary productivity (NPP): energy stored in new organic biomass minus autotrophic respiration; available to consumers
Formula (net primary productivity):
- NPP = GPP - R_a
- where R_a is autotrophic respiration; units: ext{J m}^{-2} ext{yr}^{-1} (or equivalent)

6) Highest NPP per unit area

Tropical rainforests have the highest NPP per unit area due to warm temperatures, high rainfall, and rapid plant growth; faster nutrient cycling reinforces high productivity

7) Limiting factors in aquatic ecosystems

Light and nutrient availability limit photosynthesis and thus primary productivity in aquatic systems

8) Eutrophication

An influx of nutrients (often N and P) leads to algal/cyanobacterial blooms; when these organisms die and decompose, oxygen is depleted, reducing life support for aquatic organisms

9) Open ocean productivity

Open ocean productivity is low because the photic (light-penetrating) zone is relatively thin and nutrients like N and P are limited

10) Secondary productivity

The rate at which biomass is produced by heterotrophs consuming producers; energy moves through the consumer trophic levels

11) Biogeochemical cycles: carbon, phosphorus, nitrogen

Elements move through ecosystems via reservoirs, fluxes, and biological processes
Major cycles move C, N, P among atmosphere, hydrosphere, lithosphere, and biosphere

12) Carbon cycle (conceptual map)

Atmospheric CO2 ⇄ photosynthesis by plants, algae, cyanobacteria ⇒ biomass
Respiration and decay return CO2 to atmosphere; burning of fossil fuels and volcanic activity also release CO2
Reservoirs include fossil fuels, soils and sediments, oceans, atmosphere, and biomass

13) Phosphorus cycle (conceptual map)

Weathering of rocks releases phosphate (PO4^3-)
Phosphates run off into soils and water; plants assimilate PO4^3-; animals obtain it via food
Decomposition and excretion return phosphate to the environment; precipitation forms solid phosphates
Phosphorus cycle is essential because phosphorus is a key component of DNA/RNA, phospholipids, and ATP

14) Nitrogen cycle (conceptual map)

Nitrogen fixation: N2 → NH3/NH4+ (and related organic forms) via bacteria
Nitrification: NH3 → NO2− → NO3− (nitrites and nitrates) via nitrifying bacteria
Ammonification: organic-N → NH4+ (ammonium) via decomposition
Denitrification: NO3− → N2 (return to atmosphere) via bacterial reactions
Assimilation: inorganic NO3−/NH4+ incorporated into organic molecules (amino acids, proteins)
Diagram features: atmospheric N2, plants, animals, detritus, synthetic fertilizers

15) Human population growth and environmental issues

Rapid population growth increases the human ecological footprint; greater demand for water, energy, and resources; many ecological pressures scale with population size

16) Acid precipitation (acid rain)

Emissions of sulfur oxides (SOx) and nitrogen oxides (NOx) react with water to form sulfuric and nitric acids
Effects: lowers pH of rain, soils, and water bodies; damages trees and aquatic life

17) Biological magnification (bioaccumulation)

Toxins accumulate in higher concentrations in organisms at higher trophic levels (e.g., PCBs in Great Lakes herring gulls; magnification up to ~5000x)

18) Global warming drivers

Rise in greenhouse gases (CO2, CH4, N2O, fluorinated gases) traps heat in the lower atmosphere, warming the planet
Ozone depletion, though not as directly linked to warming as greenhouse gases, can interact with climate processes

Chapter 55: Conservation Biology and Restorative Ecology (Campbell) & Chapter 43 (Urry)

1) Conservation vs Restoration ecology

Conservation biology: aims to protect and sustain biodiversity at all levels and maintain ecosystem processes to prevent extinctions
Restoration ecology: aims to repair damaged, degraded, or destroyed ecosystems and restore ecological function

2) Why biodiversity matters to humans

Provides ecosystem services and human welfare: medicines, food, pollination, soil formation, nutrient cycling, detoxification of wastes, air and water purification, climate regulation, aesthetic and recreational value
Biophilia: intrinsic human connection to nature

3) Major threats to biodiversity (four categories)

Habitat loss and fragmentation due to agriculture, urban development, forestry, mining, pollution
Introduced (non-native) species altering communities and driving natives to declines or extinction
Overharvesting (overexploitation) of wild populations
Global change (climate change, altered ocean chemistry, etc.)

4) The small population approach and extinction vortex

Small populations face inbreeding and genetic drift, leading to reduced genetic variability and fitness, which can create a downward spiral toward extinction

5) Declining-population approach (common steps)

Identify and study processes leading to shrinking populations
Determine environmental factors and threats causing declines
Develop strategies to mitigate threats and support population recovery

6) Biodiversity hotspots and their importance

Hotspots are areas with high numbers of threatened species and substantial endemism; protecting hotspots can conserve many species with relatively limited effort

7) Bioremediation

Using natural organisms to clean polluted environments (e.g., oil-degrading bacteria used to clean oil spills)

8) Sustainable development

Development that meets present needs without compromising the ability of future generations to meet their own needs
These notes summarize the major and minor points from the transcript, organized by topic and subtopic, and include essential definitions, examples, formulas, and conceptual connections relevant for AP Biology ecology and conservation units.