Introduction to Ecology and Ecosystem Dynamics

Ecology

The study of how organisms interact with their environment.

Central goal of ecology

To understand the distribution and abundance of organisms.

Four main levels of ecology

Organisms, Populations, Communities, Ecosystems.

Organismal ecology

Exploring adaptations (morphological, physiological, behavioral) allowing organisms to live successfully in a particular area.

Population

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

Population ecology

How population numbers change over time.

Community

Different species interacting with one another within a particular area.

Community ecology

The nature and consequences of interactions among species in a community.

Ecosystem

All organisms (biotic) and non-living components (abiotic) in a particular region.

Ecosystem ecology

How nutrients and energy move between organisms and their surrounding environment.

Biome

A type of terrestrial ecosystem unique to a region with distinct vegetation.

Biomes categorization

By annual precipitation and temperature.

Tropical wet forests location

Equatorial regions.

Tropical wet forests characteristics

Regular rainfall and consistently high temperatures year-round.

Subtropical deserts characteristics

High annual temperatures with moderate variation and very low precipitation.

Species adaptation to subtropical deserts

Slow growth year-round, dormancy, rapid growth after rainfall.

Temperate regions characteristics

Moderate temperatures; long warm summers and short cold winters.

Temperate grasslands

Regions with moderate temperatures, low precipitation, and distinct growing seasons.

Temperate forest definition

Warm summers, winters below freezing, and constant moderate-high precipitation.

Boreal forests location

Northern Canada, Alaska, Russia, and northern Europe (below tundra).

Boreal forests characteristics

Cold winters, short cool summers, and high annual temperature variation.

Vegetation in boreal forests

Cold-tolerant conifers (spruce, pine, fir, larch).

Arctic tundra definition

Very low temperatures, high temperature variation, low precipitation, treeless.

Freshwater ecosystems with standing water

Lakes, ponds, or wetlands.

Wetlands vegetation

Emergent vegetation (plants growing above the water surface).

Three main zones in aquatic systems

Littoral, Limnetic, Benthic (plus photic and aphotic zones).

Marshes definition

Tree-less, connected to lakes or streams, with slow water flow.

Swamps

Dominated by trees and shrubs; very productive.

Bogs

Low or absent water flow, stagnant water, and low productivity.

Streams/Rivers

Bodies of water that constantly move in one direction.

Estuary

Where a stream meets the ocean.

Population Distribution Patterns

Uniform, random, clumped.

Demography in Ecology

Study of birth rates, death rates, immigration, and emigration.

Age Pyramids

History of births and deaths in a population.

Survivorship Curves

The likelihood of dying at different ages within a population.

Density Dependence

Changes in birth or death rates relative to population density.

Species' Life History

How an organism's energy budget is divided among growth, dispersal, and reproduction.

Population Dynamics

Changes in a population size through time.

Population Cycles

Regular fluctuations in population size.

Biological Community Interactions

Competition, predation/parasitism, commensalism, mutualism, amensalism (less recognized).

What are two types of interactions between species

• Intraspecific (within species)
• Interspecific (Between/among Species)

What is competition?

Competing for resources

What are some effects of competition?

• Reduce species abundance
• Restrict species range

Competitive Exclusion Principle

Sympatric species with identical niches cannot coexist.

Fundamental vs Realized Niches

Fundamental is without competition; realized includes competition effects.

Herbivory

Consumption of plant tissues by herbivores.

Parasitism

Consumption of small amounts of tissue by one species from another.

Predation

Killing and consumption of one species by another.

Constitutive Defenses

Defenses always present in organisms.

Inducible Defenses

Defenses produced only when prey is threatened.

Mimicry

Close resemblance of one species to another or an object.

How do prey defend themselves? (KY insects examples)

- Saddleback caterpillars have poisonous spines
- Hickory horned devil have harmless spines to mimic a dangerous species
- Bombardier beetle – glandular defense system w/ warning color (apopsomatic)

Batesian and Mullerian Mimicry

Batesian: harmless mimics harmful; Mullerian: both species harmful.

Commensalism

One partner benefits, the other unaffected.

Succession

Development of communities after disturbance.

Ecosystem

Organisms and their physical environment in a particular area.

Climate

Combination of heat, moisture, and sunlight.

Trophic Levels

Producers, primary consumers, secondary consumers, decomposers.

Food Chain

Shows how energy moves from one trophic level to another.

Food Web

Entire set of interconnected food chains within an ecosystem.

Pyramid of Productivity

Highest productivity at the base trophic level, declining at higher levels.

What limits the rate at which nutrients move through an ecosystem?

Decomposition of Demetrius

Altering the phosphorus cycle causes _____ of aquatic systems?

• Eutrophication (nutrient rich water)

• Oligotrophic (nutrient poor water)

Nutrient Cycling Rates

Rate of decomposition.

Eutrophication

Nutrient enrichment causing excessive growth in aquatic systems.

Ozone Hole Location

Antarctica.

Carbon Cycle

Involves substantial exchange with oceans.