Biological Communities & Species Interaction

1. Biological Communities & Species Interaction

2. Who Lives Where and Why? • Critical Factors and Tolerance Limits 1. nutrients, temperature, water supply, living space and other physical factors 2. tolerance limits - minimum and maximum levels (range) for each of the critical factors 3. factors are unique for each species, and often complex interaction between several factors

4. Saguaro cacti are extremely Sensitive to temperature Desert pupfish, lives in desert, Can survive at high temp up to 42 C and in high salt. But eggs and juvenile fish live between 20-36C and are killed by high salt

5. Environmental Indicators Lichen and Frogs are Pollution Indicators Jimson Weed a.k.a Loco Weed, or Devil’s Weed Grows where selenium and uranium are high Datura stramonium

6. Mulefat: native plant, indicates the presence of water

7. Natural Selection, Adaptation, Evolution 1.physiological modifications - traits of species that allow them to “adapt” to environment 2. evolution by natural selection-over time, traits that are beneficial “survive” while those that are less beneficial do not 3. factors influencing evolution- change in environment; predation; competition; luck

8. A trait that provides and advantage is known as an ADAPTATION

9. Selection (Natural or Artificial)

10. The Ecological Niche 1. habitat-place and environmental conditions in which an organism lives 2. ecological niche- functional description of role of species within a community • how it obtains food • relationships with other species • role it plays in biotic and abiotic aspects of area

14. Predation 1. predator-an organism that feeds directly on another living organism • predator - prey relationships play vital a central role in evolution of many species • competitive exclusion principle - two species whose niche overlap too much will compete for resources

16. KEYSTONE SPECIE

17. Keystone Species 1. keystone species- species or group of species whose impact on community is greatest • not always the highest on the food chain i.e. Wolves limit the grazing of herbivores i.e. Sea star limits population of clams etc.

18. Parasite: A type of symbiosis in which organism that completes part of its life cycle on a host organism. The host is harmed and the predator is not. • Pathogen: Disease causing organisms that are not free living.

19. Competition 1. intraspecific competition- competition for resources among members of same species • territoriality 2. interspecific competion- competition for resources among members of different species What two ways do grasses compete? Why is intraspecific competiton more intense?

20. Symbiosis - intimate interaction of species (often with one relying on another) 1. commensalism- one organism benefits, other is neither helped nor harmed i.e. Bird in a tree 2. mutualism-both organisms benefit from a mutual relationship with each other i.e. mycorrhizae and lichen 3. parasites- one organism benefits one is harmed i.e. Sporozoan that causes malaria

21. Mimicry and Camouflage 1. Batesian mimicry- a related species evolves over time to appear similar to a dangerous species • Butterflies Left is unpalatable Right is palatable

22. Batesian Mimicry

23. 2. Muellerian mimicry- one species evolves over time to appear similar to unrelated species

24. Camouflage

25. Community Properties • Productivity - rate of biomass production • Abundance and Diversity 1. abundance- actual total number of individual organisms in a community 2. diversity- number of actual species or niches present in a particular ecosystem

26. What Is…..? • ZooPlankton • Phytoplankton • Giant Kelp

28. Complexity and Connectedness 1. complexity- number of species at each trophic level and number of trophic levels 2. connectedness- the relatedness of organisms within the entire trophic system

30. Resilience and Stability • constancy - lack of much change over time • inertia - change occurs, much resistance • renewal - ability to repair after severe damage

31. Community Structure • spatial distribution of organisms • relation of organisms to their surroundings • nesting birds • schools of fish • clusters of trees

33. Factors influencing distribution • Dispersal methods a) availability of water in the desert • Behavior • Biotic factors (predation parasitism, competition, disease) b) competition for nesting space in a penguin colony. c) clustered (optimum protection bird and fish) • Abiotic factors (availability of nutrients, water, light or presence of chemicals)

34. Community in Transition • Ecological Succession - gradual change of ecosystem over time 1. primary succesion- community develops on site with little/no biotic forms 2. secondary succession- new species begin to replace “original” species on the site 3. climax community - community that finally develops and resists any further change

37. 4. equlibrium community- undergoes periodic disruptions and renewal • forests, grasslands 5. fire-climax community - often depends upon fire for part of it normal life cycle the chaparral

39. Introduced Species - new species brought into a community 1. natural-species moves into a community without human intervention 2. human introductions- new species brought into community by humans • eucalyptus trees • Rabbits in Australia • Mongoose in Jamaica and Hawaii

40. Mongoose fighting Cobra Overgrowth of Introduced Rabbits In Australia