Habitat vs. Niche

Habitat- the place in which an organism lives out its life

Niche - the role a species plays in a community; its total way of life

A niche is determined by the tolerance limitations of an organism, or a limiting factor.

Competitive Exclusion

Principle

• No two species can occupy the same niche in

the same place at the same time.

• One species will be eliminated from a

community because of competition for the

same limited resource.

Limiting Factors

• Limiting factor- any biotic or abiotic factor that restricts the existence of organisms in a specific environment or causes population growth to decrease.

• Most of the time the limiting factor is a resource in insufficient supply.

Examples of limiting factors -

•Amount of water•Amount of food•Temperature•Amount of space•Availability of mates

Limiting Factors

Limiting Factors

• Density-dependent limiting factor — factor that only limits growth of a population when the population density reaches a certain level (overcrowding).

• Examples: food, water, shelter, competition, predation, parasitism, and disease

Limiting Factors

• Density-independent limiting factors — these limit growth regardless of the population size.

• Examples: unusual weather, natural disasters, seasonal cycles, and human activities

Resources

• Renewable Resources—a resource that can regenerate quickly and that is replaceable.– Examples: sunlight, trees, etc…

Resources

Nonrenewable Resources—a resource that cannot be replenished by natural processes.

Example: fossil fuels

CompetitionCompetition—interaction in which organisms of the same or different species attempt to use the same ecological resource in the same place at the same time.

PredationPredator/Prey—interaction in which one organism captures, KILLS, and feeds on another organism.

Symbiotic Relationships

Symbiosis- two species living togetherhttp://www.youtube.com/watch?v=zSmL2F1t81Q

3 Types of symbiosis:

1. Commensalism

2. Parasitism

3. Mutualism

Type of relationship

Species harmed

Species benefits

Species neutral

Commensalism

Parasitism

Mutualism

= 1 species

Symbiotic Relationships

Commensalism-

one species benefits and the other is neither harmed nor helped

Ex. orchids on a tree

Epiphytes: A plant, such as a tropical orchid or a bromeliad, that grows on another plant upon which it depends for mechanical support but not for nutrients. Also called xerophyte, air plant.

Symbiotic Relationships

Commensalism-

one species benefits and the other is neither harmed nor helped

Ex. polar bears and cyanobacteria

Commensalism

Whale & Barnacles

Shark & Remora

Symbiotic Relationships

Parasitism-

one species benefits (parasite) and the other is harmed (host)

• Parasite-Host relationship

Symbiotic Relationships

Parasitism- parasite-host

Ex. lampreys,

leeches, fleas,

ticks, tapeworm,

Not considered predator-prey because goal is not to KILL host

Symbiotic Relationships

Mutualism- beneficial to both species

Cleaner Shrimp & Fish

Bee & Flower

Mutualism

Egyptian

Plover

&

Crocodile

Symbiotic Relationships

Mutualism-beneficial to both species

LichenFungus

+BluegreenAlgae