Community Interactions

1. Community Interactions Relationships Between Organisms

2. Predator-Prey Relationships • Predators can affect the size of prey populations in a community and determine the places prey can live and feed • Ex: Fox and rabbit populations

3. Herbivore-Plant Relationships • Herbivores can affect both the size and distribution of plant populations in a community and determine the places certain plants can survive and grow • Ex: White tailed deer and food plants

4. Keystone Species: • A species of great importance to a community • If it’s population changes it can cause dramatic changes to structure of community

5. Ex: • Sea Otters off Pacific Coast of North America • Links to Sea urchins, kelp and many other species • http://www.youtube.com/watch?v=eYpM-qDNKzs&safe=active

6. Beavers (a keystone species) http://www.youtube.com/watch?v=kZVbKwDmr-o&safe=active

7. Symbiotic Relationships • Organisms live in close association with each other and at least one benefits. • Relationships that help one or both species to survive • Symbiotic Relationships: • http://www.youtube.com/watch?v=nRkWzLzCi2U&safe=active

8. Mutualism: • Both species benefit Ex: • Clown Fish and Sea Anemone • Ants and aphids • “Cleaning Stations” (Rhino and “Tick Bird”)

10. Ex: Protozoa in digestive tracts of termites • Termites have cellulose digesting microorganisms in their digestive tract • Provide food and a place to live • Termites could not get nutrients from wood without them. http://www.youtube.com/watch?v=CiBAq2a6qjQ&safe=active

11. Ant and Butterfly Symbiosis: • http://video.nationalgeographic.com/video/animals/bugs-animals/ants-and-termites/ant_caterpillarsymbiosis/ • Goby and Shrimp • http://www.youtube.com/watch?v=dKuWlBjUFo8&safe=active

12. Commensalism: • One species benefits, the other species is neither harmed nor benefitted • Ex: Remora and pilot fish and shark • Eats scraps from sharks meal • Barnacle and whale • Whale travels about, allowing them to get a constantly new supply of food

13. Parasitism: • One organism benefits and the other is harmed • Generally parasites weaken, but do not kill the host • EX: • Tapeworms in digestive tract • Mistletoe plant: sends roots into host plant and absorbs water, minerals and nutrients • Cowbird (brood parasite) • Leeches, Ticks, Fleas, Lice (feed on blood and skin of animals)

14. Check out this Crazy Fungal Parasite! • Cordyceps: http://www.youtube.com/watch?v=XuKjBIBBAL8&safe=active • Body Invaders: • http://www.youtube.com/watch?v=vMG-LWyNcAs&safe=active

15. Symbiotic Relationships: • http://www.youtube.com/watch?v=zSmL2F1t81Q&safe=active

16. Ecological Succession

17. Succession in Communities • Changes that take place to communities over time (especially after disturbances). • Living organisms alter their environment making it more suitable for some, less suitable for others • Original organisms slowly replaced by others until climax community is reached • Takes decades or even centuries to develop

18. Islands of Hawaii • How did they become a tropical paradise? • Started off as volcanic rock.

19. Primary Succession: • Colonization of new sites (lifeless areas) • Bare rock, new volcanic islands, sand, stream bank (no organic material present) • Slow process • Begins with soil formation

20. Soil Formation: • Starts with rocks • Erosion by wind/rain causes pieces to break off • Freezing/thawing of water causes cracks to form

21. Pioneer Organisms: first organisms to colonize barren areas Ex: Lichens: (mutualistic symbiosis between fungus/algae) • Cling to rocks, secrete acids that help break down rock • When they die, they add layer of organic material that starts soil formation http://teachertube.com/viewVideo.php?video_id=182733

22. Plants like mosses now can grow in the thin layer of soil • When they die out the soil layer gets thicker and thicker eventually allowing plants with deeper and deeper roots to thrive. • Eventually a climax community develops

23. Primary Succession

24. How Long Does it Take? • Note: • Animal life will also change with the succession of plants • Ex: grass eaters – shrub dwellers – tree livers

25. Climax Community: • Community at the end of line of succession that is mature and stable • Described in terms of dominant plant forms • Type of climax community depends on the physical factors in environment • Ex: • Good soil/good rainfall = forest community • Good soil/less rainfall = grassland community • Climax Communities: • http://www.youtube.com/watch?v=iZA5yfrzLV8&safe=active

26. Examples of Climax Communities: • Sphagnum Bog: shallow lake/pond, peat moss • Mangrove Swamp: muddy tidal flat, mangrove trees • Pine Barrens: sandy peat soil, pine trees

27. Secondary Succession • Occurs in an area where the climax community has been destroyed • However, SOIL IS STILL THERE! • Occurs at a faster rate, soil is already present. • Ex: • Forest fire, flood, volcanic explosion, human development • Succession after Fire: • http://www.youtube.com/watch?v=C2ZRe_kIRdA&safe=active

28. Pine Barrens Fire • Note: some species require catastrophe to reproduce • Ex: Certain pine cones will only release seeds if heated by fire

29. Secondary Succession Can Happen Here Soil is Established

30. Succession in Lakes and Ponds • Sediment, fallen leaves, debris gradually accumulate on the lake bottom • Plants take root in the shallower water along edge • Pond eventually becomes a marsh • Eventually fills up becoming dry land

31. Succession Summary: • http://education-portal.com/academy/lesson/ecological-succession-from-pioneer-to-climax-communities.html

32. Biomes of the Earth

33. Biomes: large geographical regions characterized by a particular type of climax community Have similar: temperature range annual precipitation sun exposure type of soil type of plants and animals

34. Temperature Differences: • Not all parts of the earth get the same amount of sunlight • Five times stronger at equator than at the poles • Seasons change due to tilt of Earth’s axis and amount of sunlight over course of the day

35. Topography: • Mountain ranges can affect rainfall patterns from one side of mountain to another • Can often see changes in plant communities with increasing altitude as temperature changes

36. Types of Terrestrial Biomes

37. Tundra • Characteristics: • Low average temp, short growing season • Long cold winters where ground is completely frozen • Only thin top layer thaws in summer, rest is permafrost • Average precipitation 10-12cm per year (mostly snow) http://education-portal.com/academy/lesson/biomes-tundra-taiga-temperate-grassland-and-coastlines.html

38. Tundra • Vegetation: • lichens, moss, grasses, sedges, shrubs • Almost no trees due to permafrost and short growing season • Nutrient poor soil due to slow rate of decomposition (nutrients recycled slowly)

39. Tundra • Animals: • Reindeer, mush oxen, caribou, wolves, arctic hares, arctic foxes, lemmings, snowy owls • During warm season: a lot of insects like flies and mosquitoes bring birds, ducks, geese to nest and breed in safety because of relative absence of certain predators

40. Taiga • Characteristics: • Cold severe winters, short mild summers • Ground thaws completely in summer (no permafrost), so can support tree growth • Precipitation 35-40cm a year with a lot of fog http://dsc.discovery.com/tv-shows/other-shows/videos/assignment-discovery-shorts-iii-biomes-taiga.htm

41. Taiga • Vegetation: • Mostly coniferous pines, firs, spruce (evergreens) • Soil often acidic due to pine needles

42. Taiga • Animals: • Moose, wolves, bears, lynx, deer, elk, wolverines, martens, snow shoe hares, porcupines, rodents, birds, insects

43. Deserts • Characteristics: • Driest biome • Sandy soil, nutrient poor • Rainfall less than 25 cm per year (arid) • Temp. varies widely during day

44. Deserts • Vegetation: • Special adaptations to conserve water • Widespread shallow roots to get maximum water when available • Cactus, yucca, mesquite trees, sagebrush, creosote bushes

45. Deserts • Animals: • Many active at night, sleep during day due to heat • Adaptations to conserve water and radiate excess heat • Fennec, snakes, lizards, spiders, scorpions, foxes, coyotes, hawks, owls, kangaroo rat http://www.youtube.com/watch?v=7Ifk9IJl0A0&safe=active

46. Temperate Deciduous Forests • Characteristics: • Cold winters, hot and humid summers • Growing season about 6 months of year • Rainfall 75-150cm per year

47. Temperate Deciduous Forests • Vegetation: • Soil: thick top layer of humus • Mostly deciduous trees • Period of plant dormancy during winter (lose leaves) • Oak, maple, hickory, beech, chestnut, birch, shrubs, herbaceous plants, ferns and mosses

48. Temperate Deciduous Forests • Animals: • Many hibernate during winter • Wolf, fox, bobcat, deer, raccoon, squirrel, chipmunk, rabbits, salamanders, birds (many migrate during winter)

49. Grasslands • Characteristics: • Prairies, steppes, pampas, savannah • Occurs in both temperate and tropical climates • Rainfalls is 25-75cm per year (usually with dry season) • Soil deep and rich, (good farmland) • http://www.youtube.com/watch?v=msdY-JJilzM&safe=active

50. Grasslands • Vegetation: • Many species of grass (rye, oat, wheat) and wild flowers • Where more water present, shrubs and some trees may develop.