Ecology

1. Ecology The study of the interactions between organisms and the living and nonliving components of their environment.

2. Table of Contents: Ecology • Levels of Organization slides 3-7 • Organism Ecology (vocabulary) slides 8-9 • Ecosystems and Energy slides 10-17 • Ecosystem Recycling slides 18-20 • Populations slides 21-30 • Succession slides 31-36 • Invasive Species slides 37-41 • Modern Issues slides 42-57

3. Levels of Organization • Biosphere • The thin layer of the earth that supports life (as thin as the skin of an apple!)

4. Levels of Organization • Biomes • Any of the worlds major ecosystems, classified by predominant vegetation and characterized by adaptations of organisms to that particular environment. • Terrestrial Biomes include • Tropical forests, Savanna, Desert, Chaparral, Temperate Grassland, Temperate Broadleaf Forest, Coniferous Forest, Tundra, High Mountains, Polar Ice • Aquatic Biomes include • Lakes, Wetlands, Streams and Rivers, Estuaries, intertidal zones, oceanic pelagic zones, coral reefs, marine benthic zones

5. Levels of Organization • Ecosystem • Includes all of the living (biotic) and non living (abiotic) components within a particular place. • Biotic Components of a Pond • includes fish, turtles, plants, algae, insects, bacteria. • These interact with each other. • Abiotic Components of a Pond • water temperature, dissolved oxygen and carbon dioxide, nitrogen levels, sun light, pH level. • These are necessary for the living organisms to survive.

6. Levels of Organization • Community • Includes all of the interacting organisms within an area. • Population • Includes all of the members of a species that live in one place at a time. • Organism • The individual in a population. • Represents the simplest level of organization. • Most studies focus on the individual organism and how it has adapted to overcome the challenges in its environment.

7. Levels of Organization

8. Organism Ecology • Biotic Factors - living factors that affect an organism. • Abiotic Factors - non living factors that affect an organism. • Habitat - where an organism lives • Environmental Fluctuations • As the environment changes, an organism must be able to tolerate those changes otherwise it will stress and exhibit reduced performance or simply die.

9. Organism Ecology • Niche • Way of life or the role of an organism in its environment. • Bacteria recycle nutrients • Predators keep prey populations under control • Plants use CO2 and produce O2 also provide food for grazers.

10. Ecosystems and Energy What’s the 10% Rule?

11. Energy Transfer • A common characteristic of all living organisms is they require energy to carry out metabolic activities. • Producers • Usually photosynthetic plants (autotrophs) • Can also be chemosynthetic (certain bacteria)

12. Energy Transfer • Measuring Productivity • Gross Primary Productivity • Rate at which producers capture energy • Energy is used to make sugar which is used for repairs, for growth or cellular respiration • Biomass • Organic matter in the ecosystem • Net Primary Productivity • Rate at which biomass accumulates in an ecosystem • NPP is highest in biomes like tropical rain forests and estuaries

13. Energy Transfer • Consumers are Heterotrophs • Herbivores - consume producers • Cows, deer, mice • Carnivores - eat consumers • Mountain Lions, bald eagles, snakes • Omnivores - eat both producers and consumers • Bears, people • Detritivores - feed on dead matter • Vultures, certain beetles • Decomposers - decay complex molecules of dead tissue and wastes into simpler molecules • Bacteria, Fungus

14. Energy Transfer • Energy Flow • Energy in an ecosystem moves from one organism into another • Trophic Level • The organisms position in the sequence of energy transfers • Food Chain • A single pathway of feeding relationships in an ecosystem that shows energy transfer • Food Web • a series of interrelated food chains in an ecosystem

15. Food Chain

16. Food Web

18. Ecosystem Recycling • The Water Cycle

19. Ecosystem Recycling • The Carbon Cycle

20. Ecosystem Recycling

21. Ecology Populations: Growth, Carrying Capacity, Variables

22. Population Growth • If resources, such as food, water and habitats, were unlimited, then a population of organisms would grow in an exponential fashion. • Imagine if this growth curve represented mosquitoes, elephants or people. The earth would be over-run and all resources would be rapidly depleted!

23. Population Growth • Fortunately, in nature resources are limited. • Limited resources slow growth and if you graph numbers of organisms over time, the graph takes the shape below.

24. Population: Carrying Capacity • Notice the top of the smooth graph is labeled “carrying capacity”. • This is the number of organisms that a habitat can sustain with the available resources. • If the number of organisms exceeds the carrying capacity, the population can begin to decline.

25. Population Curve • Notice the tail on this graph. • When resources have been overused or depleted, the organisms begin to die out.

26. Population: Carrying Capacity • What happened to the reindeer on Matthew Island? • The reindeer overused their resources and exceeded the islands carrying capacity almost dying out.

27. Population Size: Variables • What other factors affect the size of a population? • Birth Rates • Death Rates • Immigration-the movement of individuals from other areas. • Emigration-the movement of individuals out of a population.

28. Population Size: Variables • If the arrows represent actual rates, what would happen to the size of the population circle if the death rate arrow was cut in half or the immigration arrow was doubled? Population Birth Rate Death Rate Emigration Immigration

29. Population Size: Variables • If the death rate arrow were cut in half or the immigration arrow was doubled, the population circle would increase in size. Population Death Rate Birth Rate Emigration Immigration

30. Population: Variables • In the United States, birth rates, death rates and emigration rate are low but our immigration rate is climbing. How is that affecting our population size?

31. Ecology Succession

32. Ecological Succession • Changes in the number and type of organisms in a community are most apparent after some type of disturbance to the habitat. • The disturbed area may be colonized by a variety of new organisms, which are gradually replaced by other organisms until a stable group of species persists within the area. • This process is called Ecological Succession.

33. Ecological Succession cont. • One type of ecological succession is called Primary Succession. • In primary succession, a new piece of new real estate, such as a volcanic island where soil and organisms are lacking, is invaded by lichens and mosses which are usually blown in as spores. • As soil develops, these organisms are overgrown by grasses, shrubs and trees that are blown in or brought in by animals. • Eventually, the area is colonized by plants that become the main form of vegetation. • This process can take hundreds to thousands of years.

34. To the right, the foreground is bare rock covered with lichens and mosses. The middle ground contains a small amount of soil with plants. The background is a stable forest. Below is an example of rock covered with lichens.

35. Ecological Succession • Secondary succession occurs when an existing community is cleared by some disturbance such as fires, glaciation, deforestation, etc. • Under these circumstances the sequence of colonization can vary but generally weeds and other opportunistic plants first invade followed by grasses or shrubs. These can then be replaced by trees species.

36. Secondary succession occurs in areas where plants were already established but were disturbed. This sequence represents a once planted field in North Carolina.

37. Ecology Invasive Species (Non-Native)

38. Invasive Species • After habitat loss and degradation, mostly due to human activity, the biggest cause of early organism extinction is the introduction of harmful invasive species into an ecosystem. • Invasive species have been intentionally and accidentally introduced in the U.S. for years. • Intentionally introduced species include • wheat, rice, corn, cattle, poultry. • Accidentally introduced species include an estimated 7100 organisms in the U.S. alone

39. Invasive Species cont. • Accidentally introduced species include • Brown tree snakes, Japanese beetles, African honeybees, zebra mussels, Formosan Termites, Burmese pythons, Gypsy moths, etc. • Species like these cost the U.S. public approximately $261,000 per minute in damage and control.

40. Invasive Species • These invasive species cause so much damage because they have no natural predators, competitors, parasites or pathogens when introduced into a new environment. • Nonnative species can reduce or wipe-out populations of many native species, trigger ecological disruption, cause human health problems and lead to economic loss.

41. Invasive Species Kudzu Vine Burmese Python Formosan Termite Gypsy Moth Catepillar

42. Ecology Modern Issues (Optional Information)

43. Ecology • Human Population Explosion • From 2 Billion in 1930 to 6 Billion in 1996 • Projected to reach over 7.8 Billion in 2050

44. World Population Projections

45. Ecology • Mass Extinctions • The last extinction occurred 65 mya probably due to an asteroid impact. • Currently organisms are going extinct at a rate unseen since the dinosaurs last died out. • By 2100, it is expected that one fifth of the current organisms will be extinct. • Why? Habitat destruction, over hunting, the introduction of predators and disease.

46. Mass Extinction 1 • The following mass extinctions were due to natural causes. • First major extinction (c. 440 mya): Climate change (relatively severe and sudden global cooling) seems to have been at work at the first of these-the end-Ordovician mass extinction that caused such pronounced change in marine life (little or no life existed on land at that time). 25% of families lost (a family may consist of a few to thousands of species).

47. Mass Extinctions 2-3 • Second major extinction (c. 370 mya): The next such event, near the end of the Devonian Period, may or may not have been the result of global climate change. 19% of families lost. • Third major Extinction (c. 245 mya): Scenarios explaining what happened at the greatest mass extinction event of them all (so far, at least!) at the end of the Permian Period have been complex amalgams of climate change perhaps rooted in plate tectonics movements. Very recently, however, evidence suggests that a bolide impact similar to the end-Cretaceous event may have been the cause. 54% of families lost.

48. Mass Extinction 4 • Fourth major extinction (c. 210 mya): The event at the end of the Triassic Period, shortly after dinosaurs and mammals had first evolved, also remains difficult to pin down in terms of precise causes. 23% of families lost.

49. Mass Extinction 5 • Fifth major extinction (c. 65 mya): • Most famous, perhaps, was the most recent of these events at the end-Cretaceous. It wiped out the remaining terrestrial dinosaurs and marine ammonites, as well as many other species across the phylogenetic spectrum, in all habitats sampled from the fossil record. Consensus has emerged in the past decade that this event was caused by one (possibly multiple) collisions between Earth and an extraterrestrial bolide (probably a comet). 17% of families lost.

50. Last Extinction Event