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Ecology of Communities

Ecology of Communities. Types of Species Interactions. Tuesday 9/5/06 Pages 397-402 Section 21-1. Species Interactions. Close interaction between species. Predation Parasitism Competition Mutualism Commensalism. Which community is most diverse? Why?.

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Ecology of Communities

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  1. Ecology of Communities Types of Species Interactions

  2. Tuesday 9/5/06Pages 397-402Section 21-1 Species Interactions • Close interaction between species. • Predation • Parasitism • Competition • Mutualism • Commensalism Which community is most diverse? Why?

  3. Tuesday 9/05/06Pages 397-402Section 21-1 Predation • Predators capture, kill, and consume prey. • Predators are adapted to role. • Prey are adapted to survive predator Which species determines the number of the other?

  4. Tuesday 9/05/06Pages 397-402Section 21-1 Predation • Mimicry • Prey evolve defenses through natural selection. • Coloration mimics poisonous organism. • Warning coloration Why is the western King Snake not colored like the Arizona King Snake?

  5. Mimicry • Batesian mimicry • One poisonous, one not • Mullerian mimicry • Both poisonous

  6. Tuesday 9/05/06Pages 397-402Section 21-1 Predation • Plant - Herbivore • Plants are defending against herbivory. • Thorns, spines, sticky hairs. • Secondary chemicals • Nicotine • Strychnine • Digitalis • Poison oak What animal group is the plant trying to discourage?

  7. Tuesday 9/05/06Pages 397-402Section 21-1 Parasitism • Parasite is helped. • Host is harmed. • Ectoparsites • Endoparasites Why does a parasite usually not kill its host?

  8. Modern Biology Pages 397-402Section 21-1 Mutualism • Both species benefit. • Lichens • 2 layers of fungi • Algae cells inside. • Algae is kept moist • Fungi get food. Are mutualism relationships species specific?

  9. Modern Biology Pages 397-402Section 21-1 Commensalism • One species benefits. • One species is not effected. • Lichens growing on a tree limb. • Cattle egrets and live stock.

  10. Modern BiologyPages 397-402Section 21-1 Competition • Results from fundamental niche overlap. • Competitive exclusion. • When two species directly compete, one will go extinct. What, most likely, is being competed for in this study?

  11. Modern Biology Pages 397-402Section 21-1 Competition • Results from fundamental niche overlap. • Character displacement • Competitors evolve to different niches. How does the Barn Owl and Red Tail Hawk demonstrate character displacement?

  12. Modern Biology Pages 397-402Section 21-1 Competition • Results from fundamental niche overlap. • Resource partitioning. • Each competing species uses a portion of the resource. • Results in less competition between species. How does the Cape may Warbler differ from the rest of the warbler species?

  13. Review Pages 397-402Section 21-1

  14. Review Pages 397-402Section 21-1

  15. Modern Biology Pages 363-365 How is a fundamental niche different from a realized niche? • Fundamental niche • Full range of interactions in ecosystem. • All potential resources • Theoretical niche as if no other organisms present Why is the realized niche shown above smaller than the fundamental niche? Key Words: Fundamental niche Realized niche

  16. Modern Biology • Pages 371-372 Ecology of Organisms • Realized niche • All resources actually used. • Competition with other organisms limits fundamental niche. • Something less than the fundamental niche. Which species out competes the other species regarding niche?

  17. Modern BiologyPages 397-402Section 21-1 Properties of Communities • Species richness. • The total number of species in an ecosystem.

  18. Modern BiologyPages 397-402Section 21-1 Properties of Communities • Species diversity. • The total number of species in an ecosystem. • Also accounts for the number of each species.

  19. Modern BiologyPages 397-402Section 21-1 Patterns of Species Richness • Closer to the equator, the greater the richness. • Reasons why: • Older communities in tropics. • Stable climate • More available energy

  20. Modern BiologyPages 397-402Section 21-1 Succession • Gradual regrowth of species after a disruption. • Two types of succession: • Primary (starts with pioneer species) • Secondary (occurs after disruption) • Fire • Flood • Storm • Human activity • Farming

  21. Modern BiologyPages 397-402Section 21-1 Primary Succession • Starts slow due to lack of minerals. • Pioneer species first appear. • Eventually soil is produced. • Grasses appear. • Shrubs appear. • Finally trees appear.

  22. Modern BiologyPages 397-402Section 21-1 Secondary Succession • Disturbance leaves just soil intact. • Secondary succession starts with grasses. • A stable climax community results. • Some communities never reach stable climax community.

  23. Energy Transfers in Communities

  24. Monday 3/23/03Pages 415-419Section 22-1 Producers • Producers use energy to produce organic molecules. • Autotrophs • Use energy to produce carbohydrates. • Most are photosynthetic. • Few are chemosynthetic.

  25. Monday 3/23/03Pages 415-419Section 22-1 Measuring Productivity • Gross Primary productivity: • The rate at which producers capture energy. • Equal to all of the carbohydrates produced using photosynthesis.

  26. Monday 3/23/03Pages 415-419Section 22-1 Measuring Productivity • Net Primary Productivity. • All organic material in an ecosystem is referred to as biomass. • All stored energy in the ecosystem. • Rate at which biomass accumulates is NPP. • GPP - carbohydrates used for living.

  27. Monday 3/23/03Pages 415-419Section 22-1 Consumers • Consumers are heterotrophs. • Obtain energy by consuming organic molecules. • Herbivores • Carnivore • Omnivore • Detritivore • Decomposers

  28. Monday 3/23/03Pages 415-419Section 22-1 Energy Flow • Energy is transferred from organism to organism. • Trophic level refers to feeding position in community • Trophic levels: • 1st level = producers • 2nd level = herbivores • 3rd level = carnivore • 4th level = second carnivore

  29. Monday 3/23/03Pages 415-419Section 22-1 Food Chains • A single pathway of energy through the ecosystem. • Approximately 10% of energy is preserved in each transfer. • 5% of sun’s energy is preserved in the producers.

  30. Monday 3/23/03Pages 415-419Section 22-1 Food Webs • Several food chains interlinked. • Better shows energy flow in an ecosystem.

  31. Monday 3/23/03Pages 415-419Section 22-1 Food Webs • Several food chains interlinked. • Better shows energy flow in an ecosystem.

  32. Wednesday 3/25/03Pages 420-423Section 22-2 Biogeochemical Cycle • Energy flows through an ecosystem. • Water and minerals recycle in the ecosystem. • Water Nitrogen • Minerals Calcium • Carbon Phosphorus

  33. Wednesday 3/25/03Pages 420-423Section 22-2 Water Cycle • Availability of water determines productivity. • Evaporation • Transpiration • Precipitation • 90% of water that evaporates in ecosystem passes through plants.

  34. Wednesday 3/25/03Pages 420-423Section 22-2 Carbon Cycle • Carbon cycle is composed of two processes: • Photosynthesis • Respiration • Autotrophs do ____. • Heterotrophs do ____. • Detritivores do ____. • Decomposers do ____.

  35. Wednesday 3/25/03Pages 420-423Section 22-2 Nitrogen Cycle • All living organisms need nitrogen (N2) • 78% of the atmosphere is composed of N2. • Only usable to a few organisms. • Nitrogen fixation • Nitrogen fixation bacteria. • Breakdown of organic material results in ammonia. • Nitrogen is returned to the atmosphere.

  36. Modern BiologyPages 397-402Section 21-1 Species-Area effect • Larger areas support higher degree of richness. • Example: islands

  37. Modern BiologyPages 397-402Section 21-1 Community Stability • How well a community with stands change. • Species richness improves stability. • Experiment • Grass plots

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