Species Area Curves

• Species area curve predicts that larger islands will have more species than smaller islands.

• S=cAz where– S = number of species– c = a constant measuring the number of

species per unit area– A = area of island (in square units)– z = a constant measuring the slope of the line

relating to S and A

Island Biogeography

• Number of species (on a plot or island) is a balance between immigration and extinction.

• If immigration exceeds extinction, then the number of species will increase.

• Number of species usually at equilibrium

Island Biogeography

• Immigration rates on islands are related to the distance from the mainland.– Close islands have greater immigration rates

than far islands• Extinction rates on islands are related to

the size of the island.– Extinction rates are greater for small islands

than for large islands

Island Biogeography

BryozoanAquatic Colonial Animals.

Mostly marine, but some freshwater.

Reproduce by budding Corals are also colonial animals.

Individual animals are called zooids.

Colony is situated in a gelatinous mass that is firm, but 99% water.

http://www.civgeo.rmit.edu.au/bryozoa/default.html

Zooid Anatomy