ECOSYTEMS AND COMMUNITIES

1. ECOSYTEMS AND COMMUNITIES

2. ECOSYSTEMS • Biotic Factors – biological influences on organisms within an ecosystem; anything that is living • Plants, birds, trees, bacteria • Abiotic Factors – physical, or nonliving factors that shape an ecosystem • Temp., rain, soil, sunlight

3. NICHE • Full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions • Place in food web • Environment • Food – what & how obtained • Competition • Reproduction – when & how

4. COMPETITION • Occurs when organisms of the same or different species attempt to use an ecological resource (any necessity of life) in the same place at the same time • Competitive exclusion principle – no two species can occupy the same niche in the same habitat at the same time

5. PREDATION • An interaction in which one organism captures and feeds on another organism • Predator – the organism that does the killing and eating • Prey – the food organism

6. SYMBIOSIS • Any relationship in which two species live closely together • Types: • Mutualism • Comensalism • Parasitism

7. MUTUALISM • Both species benefit from the relationship • Example: Ants care for the aphids and protect them from predators. The aphids produce a sweet liquid that the ants drink.

8. COMMENSALISM • One member of the association benefits and the other is neither helped nor harmed • Example: The orchid benefits from its perch in the tree as it absorbs water and minerals from rainwater and runoff but the tree is not affected.

9. PARASITISM • One organism lives on or inside another organism and harms it • Example: A flea feeds on the blood of its host and may also carry disease-causing microorganisms.

10. ECOLOGICAL SUCCESSION • Series of predictable changes that occurs in a community over time • Occurs in stages – at each stage, different species of plants and animals may be present. • As succession progresses, new organisms move in & others die out or move out. • Two types of succession—primary and secondary.

11. PRIMARY SUCCESSION • The colonization of barren land by communities of organisms is called primary succession. • Takes place on land where there are no living organisms

12. PRIMARY SUCCESSION • Pioneer species - first species to take hold in an area • Example: Lichen, which is a combination of small organisms.

13. PRIMARY SUCCESSION • Decaying lichens, along with bits of sediment in cracks and crevices of rock, make up the first stage of soil development. • New soil makes it possible for small weedy plants, small ferns, fungi, and insects to become established.

14. PRIMARY SUCCESSION • As these organisms die, more soil builds. • After some time, primary succession slows down and the community becomes fairly stable, or reaches equilibrium.

15. SECONDARY SUCCESION • The sequence of changes that takes place after an existing community is severely disrupted in some way (fire, flood, etc.) • Occurs in areas that previously contained life, and on land that still contains soil.

16. SECONDARY SUCCESSION • Because soil already exists, secondary succession may take less time than primary succession to reach a climax community.

17. CLIMATE & LATITUDE • At different latitudes, the sun strikes Earth differently resulting in different climates - cloud cover, temperature, humidity and precipitation

18. BIOMES • A biome is a large group of ecosystems that share the same type of climax community. • Because of its latitude, temperatures never rise above freezing for long, and only the topmost layer of soil thaws during the summer. • Two types – terrestrial (land) & aquatic (water)

19. TUNDRA • A treeless land with long summer days and short periods of winter sunlight

20. TUNDRA • Underneath this top layer is a layer of permanently frozen ground called permafrost. • The soil is lacking in nutrients.

21. TUNDRA • Lack of nutrients limits the types of organisms the tundra can support. • The short growing season limits the type of plants found in this biome tograsses, dwarf shrubs, and cushion plants.

22. TUNDRA • Hordes of mosquitoes and black-flies are some of the most common insects during the short summer. • Home to a variety of small mammals, including ratlike lemmings, weasels, arctic foxes, snowshoe hares, and even birds such as snowy owls and hawks.

23. TUNDRA • Musk oxen, caribou and reindeer are among the few large animals that migrate into thearea and graze during the summer months.

24. TAIGA • Just south of the tundra lies another biome that circles the north pole. • The taiga (TI guh) also is called the boreal or northern coniferous forest.

25. TAIGA • Common trees are larch, fir, hemlock, and spruce trees.

26. TAIGA • Because of their latitude, taiga communities usually are somewhat warmer and wetter than tundra.

27. TAIGA • Prevailing climatic conditions are harsh, with long, severe winters and short, mild summers. • The topsoil, which develops slowly from decaying coniferous needles, is acidic and poor in minerals.

28. TAIGA • More large species of animals are found in the taiga as compared with the tundra.

29. DESERT • The driest biome is the desert biome. A desert is an arid region with sparse to almost nonexistent plant life.

30. DESERT • Usually less than 25 cm of precipitation annually.

31. DESERT • With rainfall as the major limiting factor, vegetation in deserts varies greatly. • The driest deserts are drifting sand dunes.

32. DESERT • Desert plants are annuals that germinate from seed and grow to maturity quickly after sporadic rainfall. • The leaves of some curl up, or even drop off altogether, thus reducing water loss during extremely dry spells. • Many desert mammals are small herbivores that remain under cover during the heat of the day, emerging at night to forage on plants.

33. DESERT • Coyotes, hawks, owls and roadrunners are carnivores that feed on the snakes, lizards, and small mammals of the desert.

34. GRASSLANDS • Large communities covered with rich soil, grasses, and similar plants.

35. GRASSLANDS • Occur principally in climates that experience a dry season, where insufficient water exists to support forests. • Contain few trees per hectare. • Soils have considerable humus content because many grasses die off each winter, leaving byproducts to decay and build up in the soil. • At certain times of the year, many are populated by herds of grazing animals.

36. GRASSLANDS • Other important prairie animals include jack rabbits, deer, elk, and prairie dogs. • Many species of insects, birds, and reptiles, also make their homes in grasslands.

37. TEMPERATE FOREST • Temperate deciduous forests develop where precipitation ranges from about 70 to 150 cm annually in the temperate zone.

38. TEMPERATE FOREST • Temperateor deciduous forests are dominated by broad-leaved hardwood trees that lose their foliage annually. • Soil usually consists of a top layer that is rich in humus and a deeper layer of clay.

39. TEMPERATE FOREST • Animals include squirrels, mice, rabbits, deer, and bears.

40. TEMPERATE FOREST • Many birds, such as bluejays, live in the forest all year long, whereas other birds migrate seasonally.

41. RAINFOREST • There are two types of rain forests in the world—the temperate rain forest and the more widely known tropical rain forest. • Temperate rain forests are found on the Olympic peninsula in Washington state and in other places throughout the world, such as South America, New Zealand, and Australia.

42. TROPICAL RAINFOREST • Tropical rain forests have warm temperatures, wet weather, and lush plant growth. • The average temperature is about 250C.

43. RAINFOREST • Receive at least 200 cm of rain annually; some rain forests receive 600 cm. • One reason for the large number of niches in rain forests is vertical layering. • The canopy layer, 25-45 meters high, is a living roof & is exposed to rain, sunlight, and strong winds.

44. TROPICAL RAINFOREST: UNDERSTORY • In the understory, the air is still, humid, and dark. Vines grow from the soil to the canopy. • Leaf cutter ants harvest leaves and bring them to the ground. • Plants include ferns, broad-leaved shrubs, and dwarf palms.

45. TROPICAL RAINFOREST: UNDERSTORY • Insects are common. • The limbs of the trees are hung with a thick layer of epiphytes, plants that get most of their moisture from the air. • Birds and bats prey upon the insects.

46. TROPICAL RAINFOREST: GROUND • The ground layer is a moist forest floor. • Leaves and other organic materials decay quickly. • There is great competition for nutrients.

47. RAINFOREST • Some rain forest plants are important sources of medicinal products and hardwood trees and have provided a source of income for people. • Agricultural land is not common in rain forests.

48. RAINFOREST • Soils do not have substantial amounts of organic matter because leaf matter, which contains nutrients, disappears so quickly. • Without organic matter, once rain forest soil is exposed and farmed, it becomes hard, almost brick-like, and nutrient-poor in a matter of a few years.

49. SAVANNAH • Recieves more season rainfall than deserts but less than tropical dry forests • Warm temperatures

50. SAVANNAH • Characterized by a cover of grasses, spotted with isolated tress and small groves of trees & shrubs • Compact soils • Frequent fires set by lightening