Ecology Concepts and Species Interactions

Components of a species' environment

Abiotic (non-living) and biotic (living) factors.

Climate

Long-term patterns of temperature, precipitation, and weather.

Temperature variation

Warmer at equator, cooler at poles; varies seasonally due to Earth's tilt.

Broader temperature tolerance organisms

Those in temperate and polar zones.

Coriolis effect

Earth's rotation deflects wind and water, affecting weather patterns.

Weather patterns at 30° and equator

Equator: rising moist air = rain; 30°: sinking dry air = deserts.

Ocean currents and climate

They move warm/cold water, influencing coastal weather.

Vegetation influence on climate

By changing moisture and temperature through transpiration and albedo.

Major biomes

Rainforest, tundra, desert, grassland, forest.

Biogeographic realms and ecoregions

Realms are large regions; ecoregions are smaller habitats within them.

PGR

Population Growth Rate; positive = growing, negative = shrinking.

Exponential growth

Unlimited, fast growth with abundant resources.

Logistic growth

Growth that slows as it reaches carrying capacity.

Negative density dependence

Growth slows as population increases due to crowding effects.

Allee effects

Too few individuals can reduce survival or reproduction.

Demographics and population growth

Age, sex ratio, and reproductive rates matter.

Chaotic population fluctuations

Time-lagged feedback between generations.

Types of species interactions

Mutualism, predation, competition, parasitism, commensalism.

Lotka-Volterra model

Predicts cycles in predator-prey populations.

Predator capture rate and prey density

Due to predator saturation and handling time.

Predators influence on communities

They control prey populations and increase diversity.

Parasite

They reduce health, reproduction, or survival.

Microparasites vs. macroparasites

Micro: viruses/bacteria; Macro: worms/lice.

Types of competition

Interspecific, intraspecific, exploitative, interference.

Competitive exclusion principle

Species with identical niches can't coexist.

Resource partitioning

By resource partitioning or using different niches.

Keystone species

A species with a large effect on community structure.

Mutualism vs. symbiosis

Mutualism = both benefit; symbiosis = close living arrangement.

Mutualism existence

Both species must gain a fitness benefit.

Community vs. ecosystem

Community = organisms; Ecosystem = community + environment.

Community composition change

Gradually or abruptly depending on conditions.

Community composition determinants

Abiotic factors, interactions, and chance.

Succession

Natural change in community over time.

Primary vs. secondary succession

Primary = life colonizes a land with no soil ; Secondary = recovery an ecosystem after a disturbance of an area that had life and soil present.

Early vs. late successional species

Early = growth rate is fast, short-lived, and more dispersal seeds; Late = growth rate is slow, competitive, less dispersal seeds

Community assembly factors

Dispersal, environment, interactions, randomness.

Trophic structure

Feeding levels in a food web.

Productivity vs. biomass

Productivity = rate of making energy; Biomass = total bio mass of life

NPP

Net Primary Productivity: energy plants store after respiration.

Chlorophyll a and NPP

Reflectance measures plant productivity.

NPP affecting factors

Water, light, nutrients, temperature.

Exploitation, growth, and ecological efficiency

Exploitation = eaten; Growth = stored; Ecological = passed on.

Top-down vs. bottom-up control

Top-down = predator influence; Bottom-up = nutrient control.

Trophic cascades

Predator effects ripple through food chain.

Nutrient cycling

Movement of elements like carbon and nitrogen.

Nutrient limitation

Lack of nutrients restricts growth.

Importance of biodiversity

Supports stability, resources, resilience.

Species-area relationship

Larger area = more species.

Habitat complexity and species

More complexity = more niches.

Environmental change and richness

Can raise or lower species count.

Disturbance and biodiversity

Moderate disturbance increases diversity.

Island biogeography

Species richness based on island size and isolation.

Island equilibrium determinants

Balance between immigration and extinction.

Tropics diversity

Stable climate, high productivity, less glaciation.

Island biogeography and reserve design

Larger, connected reserves protect more species.