Ecology Chap 4

Monday-AgendaNotes

Lab- Parrot IslandCastle learning**

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Topics-ClimateInteractionsSuccessionBiomes

What is a niche?

…it is the role or job of an organism in it’s environment.

It includes what it eats, where it lives, etc…

What is a habitat?

…is where the organism lives.

EX: a pond, a tree or a hole in the ground!

Community Interactions

Symbiosis Organism A Organism B

Commensalism + oMutualism + +Parasitism + -

Commensalism: One partner living on the other with no obvious effect on the second.

Parasitism: One partner living on the other with detrimental effect on the second.

Mutualism (symbiosis in a strict sense): Advantages for both partners.

Predation Versus Parasitism

Predators get their food from prey, but they do not take up residence on or in the prey.

• Parasites get their food from hosts, and they live on or in the host for a good part of their life cycle; they may or may not kill the host.

Common flea Heart worm

What type of symbiosis?

Commensalism Parasitism

What type of symbiosis

Mutualism Mutualism

What type of symbiosis?

Mutualism Parasitism

Rhyzobia on plant roots

Dynamics of Predator-Prey Interactions

• Many of the adaptations of predators and their victims arose through coevolution.

• The dynamics depend on: – the carrying capacity of prey population in the

absence of predation, – the reproductive rates of the prey and predator, – the behavioral capacity of the individual predators

to respond to prey density.

Carrying Capacity

• number of individuals who can be supported in a given area within natural resource limits

• Limiting factors -cause population growth to decrease– Food availability– Human disturbances– Predation– Disease

Example of a Limiting Factor

• In mountainous regions and high latitudes, timberline is the limit of tree growth. Trees cannot grow above the high timberline because water remains frozen at the low temperature for most of the year. In this case, timberline, or more specifically, temperature is the limiting factor for tree density and distribution.

Exponential Growth -unlimited resources, continuous growth

Logistic Growth- carrying capacity of 700 cells is reached

Primary succession

Secondary Succession