Species, Interactions, Succession, and

NicheHow do it all fit together?

A group of organisms genetically similar enough to have viable (fertile) offspring.

Breeding within the species = Intraspecific breeding and results in offspring of that species.

Breeding between differing species = Interspecific breeding and results in a hybrid.

Hybrids are almost always sterile.

Species

Generalists live in many types of places, eat a variety of foods, and tolerate a wide range of environmental conditions.

Specialists typically live in only one type of habitat, eat a limited variety of foods, and tolerate a narrow range of environmental conditions.

Generalists vs. Specialists

Indicator species serve as “early warning systems” for ecosystem damage. (Canary in a coal mine)

Keystone species have a role in an ecosystem that is larger than their abundance or biomass would suggest.

Indicator and Keystone Species

Interspecific Competition – two or more species compete for food, space, water, or any other limited resources.

Predation – members of one species (predator) feed directly on all or part of an organism of a differing species (prey).

Interactions

Interference Competition – one species limits another species access to resources, regardless of their abundance.

Exploitation Competition – one species is able to exploit resource more quickly or efficiently.

Competitive Exclusion – one species eliminates another from an area through competition for limited resources.

Interactions (continued)

Long-lasting relationships in which organisms live together in a more-or-less intimate association.

Mutualism – both organisms benefit. (+,+) Commensalism – one organisms benefits

and other is (seemingly) unaffected. (+,o) Parasitism – one organism (parasite) feeds

on another organism (host) for a significant portion of the host’s life. (+,-)

Symbiotic Relationships

Primary Succession – development of a biotic community from an essentially lifeless area where no soil or bottom sediment exists.◦ Pioneer species◦ Early successional plants◦ Midsuccessional plants◦ Late successional plants◦ Climax community

Ecological Succession

Primary Succession

Secondary Succession – occurs where intact, natural vegetation has been disturbed, removed, or destroyed.

Ecological Succession (cont.)

Secondary Succession

Fundamental Niche – the full potential range of resources an organism could use if no competition were present.

Realized Niche – what an organism is able to achieve given the competition that exists.

Limiting Factors – those factors which keep an organism from realizing its fundamental niche.

Ecological Niche

Answer questions 1 and 2 on page 154 of your textbook.

Due Monday, October 3, 2011.

Homework