Chapter 4: Species Interactions and Community Ecology (Video Notes)

Flashcards cover key concepts from ecology, species interactions, energy flow, biomes, disturbance and restoration, and related terminology from the notes.

What is the biosphere?

The sum total of living things on Earth and the areas they inhabit.

What does ecology study?

The interactions between organisms and their environments.

What is an organism?

A single living thing.

What is a population?

A group of individuals of the same species in the same area at the same time.

What is a community?

All the populations of species that live and interact in an area.

What is ecosystem ecology focused on?

The flow of energy and nutrients between biotic and abiotic parts of an ecosystem.

What is a habitat?

The environment in which an organism lives, including biotic and abiotic factors.

What is a biome?

A large region with a similar community, usually defined by dominant vegetation and climate.

What is a fundamental niche?

The full potential niche a species could occupy in the absence of competition and other interactions.

What is a realized niche?

The portion of a species' niche that is actually occupied due to competition and interactions.

What is resource partitioning?

Using shared resources in different ways to minimize competition.

What is character displacement?

The process by which competing species evolve different traits to reduce overlap.

What is competition in ecology?

Organisms competing for the same resource; can be intraspecific (same species) or interspecific (different species).

What is competitive exclusion?

When one species is the stronger competitor and excludes others from a resource.

What is predation?

An interaction where predators capture, kill, and consume prey.

How can predation affect population dynamics?

Prey abundance affects predator populations; predators become better at capturing prey; natural selection favours hunting adaptations in predators.

What is parasitism?

A relationship where one organism depends on another for nourishment, usually without killing the host.

What are pathogens?

Parasites that cause disease (e.g., malaria, tuberculosis, hepatitis).

What is coevolution in host–parasite interactions?

Parasites and hosts adapt to each other over time.

What is herbivory?

An herbivore feeds on plant tissues; plants evolved defenses like chemicals and thorns.

What is mutualism?

A relationship where two or more species benefit from each other.

What is symbiosis?

Close physical association between species, which can include mutualism, commensalism, or parasitism.

What is pollination?

The transfer of pollen from flower to flower, enabling fertilization; often facilitated by birds or insects.

What is commensalism?

A symbiotic relationship where one organism benefits and the other is unaffected.

What is a keystone species?

A species with a disproportionately large impact on its ecosystem relative to its abundance.

What is a trophic cascade?

A ripple effect when top predators are lost, leading to changes across trophic levels and ecosystem structure.

What is a disturbance in ecology?

An event with rapid, drastic effects on a community or ecosystem (e.g., storms, fires, insect outbreaks).

What is resistance in ecological disturbance?

The ability of a community to resist changes from a disturbance.

What is resilience in ecological disturbance?

The ability of a community to recover its original state after a disturbance.

What is succession?

A series of changes in a community following a severe disturbance.

Who are pioneer species?

The first species to colonize disturbed areas (e.g., lichens, grasses).

What is a climax community?

A relatively stable, mature community that remains until another disturbance occurs.

What is primary succession?

Succession that starts where there is no soil life (e.g., lava flows, bare rock).

What is secondary succession?

Succession following a disturbance where soil life remains.

What is a regime shift?

A large-scale, abrupt change in the structure and function of a community due to disturbance or climate.

What is a no-analog community?

A community comprising species that have not coexisted previously, often due to human disturbance.

What is an introduced species?

A non-native species introduced by humans to a new area.

What is an invasive species?

An introduced species that becomes established and spreads, causing ecological or economic damage.

What is ecological restoration?

Restoring altered areas to function more like pre-disturbance ecosystems.

Why might re-creating a 1800s ecosystem be unrealistic today?

Climate change and shifting species distributions mean current conditions differ from the past.

What is a climatograph?

A diagram showing seasonal changes in temperature and precipitation.

What factors determine a biome's classification?

Dominant vegetation type and climate (temperature and precipitation patterns).

What is the rainshadow effect?

Moist air rises over a mountain, cools and precipitates on the windward side; deserts form on the leeward side.

How do latitude and elevation influence biomes?

They affect temperature and precipitation, shaping where biomes occur.

What is a food chain?

A linear sequence showing energy transfer from one organism to the next.

What is a food web?

All the interlinked feeding relationships in a community showing energy flow.

Who are producers in an ecosystem?

Organisms that make their own sugars via photosynthesis or chemosynthesis.

What are primary, secondary, and tertiary consumers?

Primary consumers eat producers; secondary eat primary; tertiary eat secondary.

What are detritivores and decomposers?

Detritivores scavenge waste and dead matter; decomposers break down nonliving matter and recycle nutrients into soil.

What is the 10% rule in energy transfer?

About 10% of the energy at one trophic level is transferred to the next; the rest is used or lost as heat.

What is biomass?

The total mass of living matter at a given trophic level or area.

What is the difference between weather and climate?

Weather is short-term conditions; climate is long-term patterns over decades to centuries.

What is a producer-consumer relationship in a food web?

Producers create energy, consumers eat those producers or other consumers, transferring energy through the system.