Interactions in ecosystems Interactions between organisms Populations in
Interactions in ecosystems
Interactions between organisms • Populations in a community interact together • Among these interactions ecologists have defined: - Competition - Predators and prey (predation) - Symbiotic relationships (symbiosis) - Coevolution
Worksheet
Plenary
Starter • https: //www. youtube. com/watch? v=sjyu. IYz. N qe. I
Objectives • Differentiate between intraspecific and interspecific competition • Describe the predator prey relationship
Competition • Because resources are limited in an ecosystem, competition arise. • It may occur over food, water, shelter, space or sunlight. • It may be between members of the same species (intraspecific) or between members of two different species (interspecific) 20
Intraspecific competition
Interspecific competition high tide Chthamalus area of competition Balanus low tide
Ecology of Communities • Predator-Prey Interactions – Predation • One living organism, the predator, feeds on another, the prey 23
Predator adaptations • Predators have adaptations that help them to catch preys • Some have adapted speed (cheetah) • Some have adapted poison (cobra) • Some have adapted building trap (spider) • http: //www. youtube. com/watch? v=Ih. DS 7 YN_l. II
Predator-prey Interaction Between a Lynx and a Snowshoe Hare a. 140 Number (thousands) 120 hare lynx 100 80 60 40 20 1845 1855 1865 1875 1885 1895 1905 1915 1925 1935 b. 25
Ecology of Communities • Prey defenses – Mechanisms that thwart the possibility of being eaten by a predator • • • Heightened senses Speed Protective armor Protective spines or thorns Tails or appendages that break off Poisonous chemicals Camouflage Warning coloration Flocking behavior 26
Antipredator Defenses eye false head a. Camouflage b. Warning colorization c. Fright 27
Ecology of Communities • Mimicry – One species resembles another species that possesses an overt antipredator defense 28
Mimicry Among Insects Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. a. Flower fly b. Longhorn beetle c. Bumblebee d. Yellow jacket a: © Edward S. Ross; b: © Edward S. Ross; c: © James H. Robinson/Photo Researchers, Inc. ; d: © Edward S. Ross 29
Worksheet
- Slides: 30