1. ECOSYSTEM DYNAMICS Populations Symbiosis Succession

2. Populations Group of the same type of organism living in the same geographic area at a given time. Limiting Factors – Food Carrying Capacity - limits size Zero Growth (Steady State )

3. Measuring Populations Census – count all of the organisms in a population Direct count Sampling – count a small sample and use it to estimate the total population

4. Techniques for Sampling Quadrat Method Good for counting sessile things Construct a grid Count several random quadrats http://www.psychology.ex.ac.uk/lundy/images/quad.jpg

5. Capture-Recapture Method Assumes population remains constant Capture, mark and release organisms Capture again, use formula:

6. Population Density Need: population size and area Ex. 40 oak trees in 10 acres

7. Population Distribution Clumped Uniform/Even Random

8. Symbiosis Species Interaction Predation Predator – consumes another individual, the prey Plants – adaptations to prevent predation (thorns) http://www.public.iastate.edu/~bsbowen/ZOOL-EEOB507/images/predprey-cheetahgazelle.jpghttp://www.public.iastate.edu/~bsbowen/ZOOL-EEOB507/images/predprey-cheetahgazelle.jpg; http://www.bigfoto.com/themes/closeup/thorn-photo_if.jpg; http://www.bigfoto.com/themes/closeup/thorn-photo_if.jpg http://www.ndpteachers.org/perit/Tapeworm%5B1%5D.JPG

9. Parasitism Parasite – feeds on host, harming but not killing it Ectoparasite – external (ticks) Endoparasite – internal (tapeworm) http://www.public.iastate.edu/~bsbowen/ZOOL-EEOB507/images/predprey-cheetahgazelle.jpghttp://www.public.iastate.edu/~bsbowen/ZOOL-EEOB507/images/predprey-cheetahgazelle.jpg; http://www.bigfoto.com/themes/closeup/thorn-photo_if.jpg; http://www.bigfoto.com/themes/closeup/thorn-photo_if.jpg http://www.ndpteachers.org/perit/Tapeworm%5B1%5D.JPG

10. Competition – species compete for same limited resource (water) Mutualism – both species benefit (clown fish, sea anemone ) Commensalism – one species benefits, the other unharmed (human, apple tree) http://www.sandyart.com/Clown_Fish_.jpghttp

11. Succession The gradual change in a community over time. Primary community – development of a community where none existed before. (Bare rock succession) Secondary community – reclamation of a previously existing community (Farmer’s field succession) stableClimax community – long-term, generally stable ( Old forest community)