Ecology: Ecosystems and Communities

1. Ecology: Ecosystems and Communities Honors Biology – Chapter 4

2. The Role of Climate • Climate vs. Weather • Weather • Day to day conditions at a particular time/place • Climate • Average, year-after-year conditions in a region • Temperature • Precipitation • Climate determines what kind of biome/ecosystem can develop in an area.

3. What Shapes an Ecosystem? • Biotic and Abiotic Factors • Biotic Factors • Living things • Abiotic Factors • Non-living things • Together these things determine the productivity of an ecosystem

4. Habitat • The area where an organism lives • Includes both biotic and abiotic factors

5. Niche • An organism’s “occupation” in its ecosystem • Includes • Place in the food web • Range of temperatures the organism requires • Type of food an organism eats; how it gets its food

6. Who can share a niche? • NOBODY. • No two species can share EXACTLY the same niche within the same habitat. • Some different species can, however, share very similar niches.

7. Community Interactions • Different species within an environment do interact with each other = community • These interactions affect the ecosystem in which they live. • Three main categories of interaction • Competition • Predation • Symbiosis

8. Competition • when organisms of the same or different species attempt to use an ecological resource in the same place at the same time

9. Competition • Competitive Exclusion Principle • No two species can occupy exactly the same niche in the same habitat at the same time • There will be a winner and a loser • The loser does NOT survive.

10. Predation • One organism captures and feeds on another organism. • Predator • Does the eating • Prey • Gets eaten

11. Symbiosis • Any relationship in which two species live closely together. • 3 types • Mutualism • Commensalism • Parasitism

12. Mutualism • A symbiotic relationship in which both members benefit. • Examples • Flowers and their pollinators • Acacia tree and ants

13. Commensalism • A symbiotic relationship in which one member benefits while the other is unaffected. • Examples: • Barnacles on shellfish, whales, etc. • Cattle egrets – eat insects stirred up by cattle

14. Parasitism • A symbiotic relationship in which one member benefits and one member is harmed • Examples • Ticks • Tapeworms

15. How do we get an ecosystem? • Ecological Succession • the series of predictable changes that occurs in a community over time • Existing community of organisms is replaced by a different community over time • SIMPLE to COMPLEX

16. Two Major Types of Succession • Primary • Secondary

17. Primary Succession • Succession that occurs in an area that has NEVER had life on it before • Example: Newly formed volcanic island

18. Primary Succession • Pioneer species – species that are the FIRST to colonize barren rock • Example • Lichen • symbiotic relationship between a fungus and algae • Breaks down rock so that soil can start to form • Prepares the environment so that other living things can populate

19. Primary Succession

20. Primary Succession

21. Primary Succession

22. Primary Succession • Rock > Lichen on Rock > Soil > small plants > small animals > larger plants > larger animals

23. Secondary Succession • Succession in an area that has had life in the past, but from which the life was removed • Example: Plowed field left to return to woods

24. Secondary Succession • Usually much quicker than primary succession. Why? • Seeds already present in soil • Roots and stumps left in the soil can sometimes regenerate • Soil is usually relatively fertile due to previous presence of living things

25. Climax Community • The most stable environment that a given environment (climate) can support • The end result of succession • Some environments (due to climate) can support large amounts of life and have elaborate climax communities; many are more limited in the climax communities they can support. • Example: In our area, the climax community is a Temperate Deciduous Forest.

26. Climax Communities

27. Revisions to Succession • Ecosystems usually recover from natural disturbances • However, long termhuman-caused disturbances may be too much for an ecosystem to recover from. • It is not necessarily guaranteed that a disturbed ecosystem will recover to its same climax community.

28. Biomes • Biome – • an environment that has a certain characteristic climax community • covers a large area and is characterized by its: • Soil and climate conditions • Plant and animal groups

29. Biomes

30. Climate and Biomes • Two main factors determine climate, which in turn determines what type of biome an area can support: • Temperature • Precipitation • Note that climates are not always uniform throughout a biome • Microclimate – small area that differs from the climate around it

31. Major Biomes • Tropical rain forest • Tropical dry forest • Tropical savanna • Desert • Temperate grassland • Temperate woodland and shrubland • Temperate forest • Northwestern coniferous forest • Boreal Forest • Tundra

32. Tropical Rain Forest • Biome covers large areas of South America, Southeast Asia, Africa and Central America (in red below). Click HERE for an interactive map.

33. Tropical Rain Forest • Hot and wet year round • Poor soils • Any organic matter that hits the soil is immediately decomposed and recycled. • Diverse plant and animal life • Terms • Canopy • Understory • Found in • Central and South America • Southeast Asia • Parts of Africa, India and Australia

34. Tropical Rain Forest –Climate • 25 degree Celcius temps throughout the year. • 200-400 cm of rain each year.

35. Tropical Rain Forest - Characteristics • Home to more species than in all other land biomes combined • Soil is surprisingly poor because plants consume nutrients so quickly • Canopy and understory • Thick canopy (tree tops) blocks sun from understory • Competition for available light is fierce.

36. Tropical Rain Forest – Plant Life • Many diverse species of plants • Highly specialized and adapted to specific environments in the rain forest

37. Tropical Rain Forest – Animal Life • Rich and varied • Colorful insects and birds abundant • Reptiles • Amphibians • Small mammals • Many tree dwellers

38. Tropical Rainforest Destruction • Destruction of rain forest occurring at rapid pace due to rapid growth of human population • Many animals and plants in the rain forest biome produce chemicals that are useful in fighting disease • If these rainforests are lost, these organisms and the medicines they might provide will be lost, too.

39. Tropical Savanna (Grassland) • Abiotic factors • Wet and Dry seasons • Warm Temperatures • Frequent fires (keep it from going to forest) • Plants • Grasses • A few drought-resistant trees / shrubs • Animals • Large herbivores; large carnivores • Where found • Large parts of East Africa • Southern Brazil; northern Australia

40. Grassland – Animal Life • Tropical Grassland (savanna) • Impala; gazelles; wildebeests; elephants; zebra; giraffes

41. Desert • Shown in pale blue below. Click HERE for an interactive map.

42. Desert • Abiotic • Dry • Temperatures vary depending on location • Plants • Cactus and other drought resistant plants • Animals • Predators and some larger herbivores • Insects; reptiles • Where found: • Africa, Asia, Middle East, U.S., Mexico, S. America, Australia

43. Desert - Climate • Less than 25 cm of rain per year • Typically associated with hot temperatures, but there are “cold” deserts, too. • Temperatures are often highly variable.

44. Desert Types • Sahara Desert in Africa • NO rainfall • Hot, dry wind • Almost nothing grows here

45. Desert Types • Seasonal Deserts • At least some rainfall during the year • Plants take advantage of any rain that falls quickly and then go dormant until next rain • Southwest U.S. deserts have more even rainfall, but very sparse – • Cactus; sagebrush, etc.

46. Desert Types • Cold Desert • Found on mountains and plateaus • Brief rainy season that allows for grasses and shrubs to grow

47. Grassland • Found in the plains and prairies of North America, the steppes of Russia, veld of South Africa, and pampas of Argentina (yellow/brown below) Click HERE for an interactive map.

48. Temperate Grassland • Abiotic • Hot summers and cold winters; 4 distinct seasons • Moderate precipitation • Fertile soils • Occasional fires • Plants • Grasses – resistant to fire, drought and cold • Animals • Smaller predators (coyotes, badgers); herbivores (mule deer, rabbits, etc.) • Where found: • Central asia, North America, Australia, Central Europe, S. America

49. Temperate Grassland - Description • Vast areas covered with grasses and small leafy plants • Found in interior portions of many continents

50. Temperate Grassland – Animal Life • U.S. grassland (prairie) • Bison; prairie dog; mice; pronghorn; badger; prairie chicken; fox