Community Ecology Chapter 8

Objectives Summarize species types Evaluate competition and predation Compare and contrast symbiosis

What is a niche? Species’ way of life or functional role in an ecosystem Everything that affects its survival and reproduction – Range of tolerance for physical and chemical conditions – Types and amounts of resources it uses – How it interacts with other living and nonliving components – Role it plays in energy flow and matter cycling How is this different from a habitat?

Fundamental vs. Realized Full potential range a species’ could theoretically use if no direct competition from other species Part of the fundamental niche a species actually uses Done to avoid competition for the same resources

Generalist vs. Specialist Have broad niche – Live in many places – Eat variety of food – Tolerate wide range of environmental conditions Have narrow niche – Live in one type of habitat – Only 1-2 types of food – Tolerate narrow range of environmental conditions

Types of Species Native species Nonnative, exotic, or alien species

Types of Species Indicator Keystone

Why Should We Care About Alligators? Why are alligators considered a keystone species? How do they affect Do you think people should be allowed to kill alligators found on their property? Explain.

What might species compete for?

Intraspecific Competition What makes a good territory?

Interspecific Competition Interference CompetitionExploitation Competition

Competitive Exclusion Principle High Low Relative population density Days Each species grown alone Paramecium aurelia Paramecium caudatum High Low Relative population density Days Both species grown together Paramecium aurelia Paramecium caudatum

Reducing or Avoiding Competition

Why are Sharks Important?

Species Interaction Who Benefits? Who is Harmed? Examples Predator-Prey Parasitism Mutalism Commensalism

Predators Increase Chance of Meal

Prey Defend or Avoid Predators

How is predation different from parasitism? How are they similar?

Objectives Explain community structure Describe the theory of island biogeography

Community Structure

Ecotones and Edge Effects

Ants Birds Latitude Depth Pollution Species diversity , , , 00 0 Depth (meters) 02,0004,0006,000 Depth (meters) CoastDeep Sea SnailsTube worms Coast Deep Sea 0 2,0004,0006,000 Biodiversity

Theory of Island Biogeography High Low Rate of immigration or extinction Equilibrium number Immigration and extinction rates Number of species on island (a)

,0004,0006,0008,00010,000 Distance from New Guinea (kilometers) Number of species (percentage of sample studied)

,00010,000100,000 Area (square miles) Number of amphibian and reptile species 10 SABAMONTSERRATCUBA Hispaniola Puerto Rico Jamaica Cuba Montserrat Saba Redonda

Objectives Compare and contrast primary and secondary succession. Describe the factors that affect succession. Evaluate the three types of stability

How do ecosystems respond to change? What happens after a forest fire? What happens after a volcano? What happens when climate changes?

Primary Succession

Secondary Succession

Succession and Wildlife

PrimarySecondary

Primary or Secondary?

Disturbance and Succession Intermediate Disturbance Hypothesis Percentage disturbance Species diversity

Succession Predictability Old View – predictable sequence leading to a climax community New View – ongoing process impacted by chance and biodiversity

Ecological Stability Inertia – persistence, resist change Constancy – maintain within limits, population Resilience – recover Does diversity = stability?

Ecological Sustainability If diversity ≠ stability why conserve? Precautionary principle

Succession, Disturbance and Stability Draw a picture showing how disturbance can increase diversity. How is succession involved? How is stability involved?