Warm Up List the 4 biogeochemical cycles: 1 ECOSYSTEM DYNAMICS Populations Symbiosis Succession Populations Group of the same type of organism living in the same geographic area at a given time. Limiting Factor Causes a population to decrease in size. Examples: food, water, shelter, space Sunlight in a rainforest = limiting factor Carrying Capacity - maximum population size that an environment can contain 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 Techniques for Sampling Quadrat Method Good for counting sessile things Sessile = NON MOVING Construct a grid Count several random quadrats Capture-Recapture Method Assumes population remains constant Capture, mark and release organisms Capture again, use formula: Mark Recapture of Snakes https://www.youtube.com/watch?v=5DR50IgvE7g https://www.youtube.com/watch?v=5DR50IgvE7g 7 Population Density Need: population size and area Ex. 40 oak trees in 10 acres Population Distribution Clumped Uniform/Even Random Symbiosis Species Interaction Predation Predator consumes another individual, the prey Plants adaptations to prevent predation (thorns) Parasitism Parasite feeds on host, harming but not killing it Ectoparasite external (ticks) Endoparasite internal (tapeworm) 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) Symbiosis Examples https://www.youtube.com/watch?v=8rSlA_ywEec https://www.youtube.com/watch?v=8rSlA_ywEec 13 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 (Farmers field succession) Climax community long-term, generally stable ( Old forest community)