Ecology andEcosystems

Advanced Biology

Montgomery High School

What is Ecology?

• Study of how organisms interact with each other and their physical environment.

• Fundamental unit is the “ecosystem”– Vary in size– Composed of biotic (living) and abiotic

(nonliving) material– May be terrestrial (land) or aquatic (water)

Terrestrial ecosystems are called biomes.

African Savanna

Rain Forest

Wetlands

Tundra

Desert

Washington State:Rain Shadow

Aquatic Ecosystems

Oceanic Ecosystems

Trophic levels = energy flow

• Producers make food from sunlight.

• Consumers eat others to get their energy.– Herbivores eat plants– Carnivores eat “meat”– Omnivores eat everything (plant and animal)– Decomposers eat dead things (plant and

animal) and release the nutrients bound up in their bodies for reuse.

Food Web

Owl Pellets

Energy Flow

ThroughTrophic Levels

•Energy is lost at each step in an ecosystem

•From one trophic level to another, the transfer of energy is not 100% efficient. “10% rule”

•Energy is lost when it is converted to unusable heat at each step.

Ecological Pyramids:Energy

Ecology

• Materials cycle within ecosystems:

– Water cycle.

– Carbon cycle.

– Nitrogen cycle.

– Phosphorus cycle.

Water Cycle

Carbon Cycle

Nitrogen Cycle

Phosphorus Cycle

Interaction of organisms

• Symbiosis: two or more organisms live together in more or less permanent relationships.

– Commensalism.

– Mutualism.

– Parasitism.

Commensalism

• Clownfish and sea anemone, Coral Sea, Australia

Mutualism

• Ants and aphids.

Parasitism

• Ectoparasites:– Lice, animal parasite.– Dodder, plant parasite.

• Endoparasites:– Tapeworm, animal parasite.

Predator-Prey Interactions

• Plant defense systems:

– Toxic or repellent chemicals.

• Animal defense systems:

– Coloration.

– Chemical.

• Predator-prey cycles.

• Mimicry: Monarch vs. Viceroy butterflies.

Community Stability

• Ecological succession:

– Primary succession.

– Secondary succession.

Biodiversity = Species Richness

Threats to Biodiversity

•Loss of habitat (increased human population)

•Pollution

•Introduction of non-native species

Biomagnification of DDT in a Food Chain