Ecosystems and Living Organisms Chapter 4 Ecosystems and Living Organisms

Evolution Genetic changes in a population through time. Occurs through natural selection Overproduction Variation Struggle for existence Differential reproductive success

Evolution Darwin’s Finches

Evolution Kingdoms of Life

Biological Communities Rotting Log Community

Biological Communities Succession: How Communities Change over Time Primary succession – Rocks Lichens Mosses

Biological Communities Succession: How Communities Change over Time Primary succession – Rocks Lichens Mosses Grasses Shrubs

Biological Communities Succession: How Communities Change over Time Primary succession – Rocks Lichens Mosses Grasses Shrubs Trees

Biological Communities Secondary Succession

Interactions Among Organisms Symbiosis – one species living in or on another species results from coevolution

Interactions Among Organisms Symbiosis – Three types 1) Mutualism With mycorrhizae Without mycorrhizae

Interactions Among Organisms Symbiosis – Three types 2) Commensalism Epiphytes

Interactions Among Organisms Symbiosis – Three types 3) Parasitism Tracheal mites

Interactions Among Organisms Predation – predators consuming prey Most common method: Pursuit and Ambush

Interactions Among Organisms Animals that consume plants = herbivores Animals that consume animals = carnivores (can be further subdivided based on prey type, such as an insectivore)

Interactions Among Organisms Defenses against predators: Plant defenses – spines, thorns leathery leaves toxic chemicals thick waxes

Interactions Among Organisms Defenses against predators: Animal defenses – armor, spines toxic chemicals

Interactions Among Organisms Defenses against predators: Animal defenses – armor, spines toxic chemicals camouflage running away

Interactions Among Organisms Competition – individuals attempting to utilize common resources Intraspecific competition Interspecific competition

The Ecological Niche An organism’s adaptations, use of resources, lifestyle, and habitat. Fundamental vs. Realized Niche Example: Tale of Two Anoles Green Anole Brown Anole

The Ecological Niche Fundamental vs. Realized Niche Fundamental Niche of Green Anole Fundamental Niche of Brown Anole Overlap Brown anole out-competes green anole, therefore . . .

The Ecological Niche Fundamental vs. Realized Niche Realized Niche of Green Anole Realized Niche of Brown Anole Overlap

The Ecological Niche Limiting Resources

The Ecological Niche Competitive Exclusion

The Ecological Niche Competitive Exclusion

The Ecological Niche Competitive Exclusion

The Ecological Niche Resource partitioning

Keystone Species Single species that strongly influences an entire community. Example: figs - frugivores depend upon fruit - usually avoid figs, but during certain times of the year, figs are only species bearing fruit - if figs were eliminated, many frugivores would die out

Species Richness Number of different species in a community

Species Richness Forest Grassland ECOTONE Where edge effect occurs Typically greater species richness

Species Richness Species Richness and Ecosystem Services Ecosystem Forests, Grasslands Purify air / water Produce / maintain soil Absorb CO2 Wildlife habitat Freshwater systems Moderate water flow Mitigate flooding Dilute / remove pollutants Drinking water Recreation

Species Richness Species Richness and Community Stability Greater the richness = Greater the stability