Communities and Biomes

1. Communities and Biomes

2. Predator-Prey One population benefits at the expense of the other.

3. Predators • Results in the fates of predator and prey populations being intimately intertwined. • Population size fluctuates due to this relationship • Preying most successfully on the slowest, weakest, least fit members of their target population • Reducing competition • Preventing excess population growth • Allowing successful traits to become dominant in the prey population • Predation may lead to extinction • Seen with introduced species. Two categories of predator-prey relationships.

4. Lynx and Hare Pelts Sold to the Hudson’s Bay Company Number of organisms(in thousands) Times (in years) Prey • Herbivore-carnivore • Prey populations may increase, followed by increases in predator populations, • followed by decrease in prey populations, followed by decrease in predator populations

5. Plants are Prey too…Herbivore vs. Producer Herbivores have developed adaptations to deal with fluctuations in available food supplies: • Put on extensive layers of fat during seasons of abundance. • Some will migrate to where food is available. • Others hibernate during seasons of hardship. • Respond to seasons of scarcity by making do with foods of relatively low nutritional value.

6. Plants respond to herbivores by: • Producing enough tissue for herbivores and still survive • Produce distasteful chemicals that deter further feeding • Produce chemicals that affect herbivores’ physiology

7. Herbivore-Carnivore Interactions • Compared to plant material, animal material is • Easier to digest • Energy and nutrients are more concentrated • Drawback: • Herbivores are mobile • Dangerous when cornered • Mimicry

8. Competition • Intraspecies—arising or occurring within a species; involving the members of one species INTRA— m o n g u s Remember—hyenas compete with each other for rank (hierarchy), food, mating rights and territory

9. Plants have developed mechanisms to cope with intraspecific competition. • Seedlings unable to germinate in the shady conditions created by parent plants. • Plants disperse seeds to other sites by water, air, or animals. • Plants secrete substances that inhibit the growth of seedlings near them.

11. Animals have developed mechanisms to cope with intraspecific competition. • Varied life cycles ( e.g. different habitats and feeding in juvenile and adult invertebrates) • Occupy different ecological niches. • Territoriality: intense form of intraspecific competition in which organisms define an area surrounding their home site or nesting site and defend it.

12. How would this help the population (increase survival)??? • Help allocate resources of an area by spacing out the members of a population • Promote dispersal into adjacent areas

13. Competition • Interspecies—existing or occurring between species b INTER— t w e e n 2

14. When Populations Compete, Both are Harmed • Law of competitive exclusion:no two species will occupy the same niche and compete for exactly the same resources in the same habitat for very long. • One species will have a competitive edge, and will gain a larger share of resources. • Other species will migrate to a new area, become extinct, or change its behavior in a way to minimize competition. • Process of niche evolution is called resource partitioning. • Niche specialization can create behavior separation that allows subpopulations of a single species to diverge into separate species.

15. Competition may cause competitive exclusion, the elimination of one species in a community. • Examples: • Paramecium • Wasps • Barnacles

16. Resource partitioning • The use of resources that are scarce in a given environment by different species at different times, different places or in different ways.

17. Warbler Foraging Zones

20. Character Displacement • Competition may drive the evolution of niche differences among competitors. • This evolution of differences in a characteristic due to competition is called character displacement.

21. Community Members That Don’t Fit the Model • Omnivores: Tend to eat everything • In some instances, function as top carnivores • Detritivores • Organisms that eat dead stuff • Example: Fungi, bacteria, earthworms, and vultures

22. How Do Human Activities Affect the Environment? Humans dominate the ecosystems throughout the Earth. • We work to create environmental conditions similar to a tropical grasslands biome. Our increasing numbers and dependence on fossil fuel affect ecosystems worldwide, producing many environmental problems: • Overpopulation • Habitat modification and destruction • Destruction of the ozone layer • Water and air pollution

23. Symbiosis • An intimate relationship between two members of different species • Three types • Mutualism • Commensalism • Parasitism

24. Mutualism • Intimate relationships in which both species benefit. • Most fascinating and important relationships known in biology. • Example: • Flowers and pollinators • Example: • Ants and the Acacia trees- ants attack any animal that tries to eat the tree. The tree provides food and shelter for the ants. • Any others?

25. Commensalism • One species benefits and the other is neither harmed nor benefited • Example: • Moss on a tree. The moss is helped and the tree is not harmed or helped • Sea anemones growing on the backs of crabs • Any others?

26. Parasitism • One species benefits and the other species is harmed • Usually do not kill the host Generally does not result in extinction of the host • Can reduce population numbers • Example: • Ticks on a dog or cat. The tick is benefited and the dog or cat is harmed. • Examples: Tapeworms, Mosquitoes, Any others?

27. Biological communities constantly change Due to: • Ecological succession • One biological community replaces another. • Triggers changes in • The physical and biological environments that set the stage for still another community

28. Succession • The gradual supplanting of one community of plants/animals by another.

29. Primary Succession • Takes place on land where there are no living organisms. • Examples: lava flowing from a volcano, a tsunami, glaciers

30. Ecological Succession at Glacier Bay

32. Example of Primary and Secondary • secondary succession • primary succession island

33. Secondary Succession • Sequence of changes that take place after an existing community is severely disrupted in some way. • Occurs in areas that already contain life and on land that contains soil. Ex. Fire • Secondary—restarts with soil (fire, severe flood, hurricane, tornado, mining, logging, construction, etc.) Fire Several years after fire

35. Climax forest begins with a disturbance such as a fire…

36. Lake Succession Starts with a lakebog grassland on and on

37. Speciesrichness • the number of species in a community. • What places would be species rich? • Does that mean the same thing as species diverse? Explain what you mean.

38. Latitude and Species Richness • In general, species richness is greatest near the equator, and larger areas support more species. • Why does that make sense?

40. Biomes and Aquatic Ecosystems Please have out your chart so you can check your work…

44. Dryer than savannas—that’s why there are no trees/shrubs Less tropical—no trees Grass is more drought tolerant and fire tolerant RICH soilmost turned into the best farmlands in the world—corn and wheat AKA Veldts of South Africa Puszta of Hungary Pampas of Argentina/Uruguay Steppes of Russia / China Plains and Prairies of North America a wide range of variability in temperature and precipitation more rainfall—trees mix with evergreens oak, beech, birch and maple Eastern US and Central China have riches forests Specialists here because late succession stages allow for greater biodiversity Sensitive to disturbances—fire and exotic species Temperate Grassland What are the biomes of NE OK? Deciduous (Temperate) Forest

45. Tropical Rainforest • Temperate Forest • Taiga

46. Desert • Temperate Grasslands • Tundra

47. Chaparral • Savanna

48. Ocean Zones • The photic zone in the ocean receives light, but the aphotic zone does not. • Other zones of the ocean are defined based on their relative locations.

49. Aquatic and Marine • Freshwater- ecosystem in which (non-salty) water of streams, rivers, ponds, or lakes plays a defining role. • Marine- (Covers 70% of the earth’s surface) Living in or related to the sea

50. Lakes, ponds, streams More sun More producers More diversity Oceans More sun More producers More diversity Intertidal zone Near hydrothermal vents Chemoautotrophs… Diversity in Aquatic Ecosystems… It’s all about the pyramids and webs…a strong base (diverse and/or abundant amount of producers!!!