Ecology & Biodiversity

1. Ecology & Biodiversity Unit 3 AP Environmental Science

2. Terminology • Ecology: the study of how species interact with one another & their surrounding environment. • Biodiversity: the variety of the Earth’s species • Functional diversity: energy flow & matter cycling needed to sustain ecosystems. • Genetic diversity: variety of genes within a population • Ecological diversity: variety of ecosystems on Earth • Species diversity: number & abundance of species in communities

3. How do Organisms get Energy? Photosynthesis: Converting light energy (from the sun) into usable chemical energy Producers

4. How do Organisms get Energy? Cellular Respiration: The process of breaking down simple sugars to release energy. Producers & Consumers Aerobic: oxygen present Anaerobic: oxygen not present (fermentation)

5. How do Organisms get Energy? The Sun is the ultimate source of energy on Earth

6. How do Organisms get Energy? • Chemosynthesis: process in which organisms convert inorganic chemicals (H2S or H2) into usable energy. • Deep-sea hydrothermal vents • Hot springs • Intensely salty lakes • Deep in rock formations • Deep-sea (w/o thermal vents)

7. Levels of Organization in an Ecosystem Species: all organisms of the same kind that are genetically similar to breed in nature and produce fertile, live offspring. Population: all members of the same species living in a given area at the same time. Community: all populations interacting together in a given area at the same time. Ecosystem: a community and its environment (abiotic – nonliving factors) (biotic – living factors)

8. Transferring Energy in an Ecosystem • Producers: organisms the photosynthesize • Productivity: amount of biomass produced in a given period of time. • Biomass: biological material • Food Chain: a linked feeding series • Food Web: a diagram of interconnected food chains

9. Transferring Energy in an Ecosystem • Trophic Level: an organism’s feeding status in an ecosystem • Producer • Primary Consumer (Herbivore) • Secondary Consumer (Carnivore, Omnivore) • Tertiary Consumer (Carnivore, Omnivore) • Quaternary Consumer (Carnivore, Omnivore) • Consumer: eat producers for energy • Herbivore: eats only plants • Carnivores: eat flesh (meat) only • Omnivore: eats both plants and animals

10. Transferring Energy in an Ecosystem • Other Consumers: • Scavengers: eat and clean up dead carcasses of larger animals. • Crows, jackals, vultures • Detritivores: eat litter, debris, dung • Ants, beetles • Decomposers: complete final breakdown and recycling of organic materials. • Fungi, bacteria

11. Transferring Energy in an Ecosystem Consumers that feed at all levels: Scavengers & Decomposers

12. Transferring Energy in an Ecosystem ONLY 10% of Energy moves to the next trophic level!

13. Transferring Energy in an Ecosystem Pyramid of Numbers

14. Transferring Energy in an Ecosystem Biomass Pyramid

15. Transferring Energy in an Ecosystem Energy Pyramid

16. Biogeochemical Cycles Hydrologic Cycle (aka water cycle):

17. Biogeochemical Cycles • Carbon Cycle: • Needed to make organic molecules • Bonds with carbon contained “stored” energy

18. Biogeochemical Cycles • Nitrogen Cycle: • An element needed in making organic molecules • Assimilation: the taking in of nitrogen by plants • Nitrogen fixation: bacteria combine N with H to form NH3 (ammonia) • Nitrification: bacteria turn ammonia into nitrates (NO3) • Denitrification: bacteria convert NO3 into N2

19. Biogeochemical Cycles • Phosphorous Cycle: • More phosphorous = more lush plant growth but also more water pollution • Phosphorous has NO atmospheric form

20. Biogeochemical Cycles • Sulfur Cycle: • Important for making proteins

21. Speciation & Evolution • Adaptation: acquisition of traits that allow a species to survive in its environment. • Acclimation – immediate response to a changing environment, but not past on genetically • Natural Selection – • organisms better suited to the environment survive  • offspring inherit the beneficial traits  • over generations, these become the traits of a population • Evolution brought on by an accumulation of mutations over time.

22. Speciation & Limitations • Limitations to where a species can live • Physiological factors • Moisture, temperature, light, pH, or a specific nutrient • Competition with other species • Predation, parasitism, disease • Luck • An organisms design may allow it to only live within certain conditions • Critical Factor: the single factor in shortest supply relative to demand. • Saguaro Cactus – so sensitive to freezing temperatures that one freezing night below O for 12 hours or more stunts its growth, and it can no longer develop.

23. Speciation & Limitations Tolerance Limits: each factor has a minimum and maximum level in beyond which a species would not be able to survive or reproduce.

24. Speciation & Ecological Niches • Habitat: place or environmental conditions in which a species lives. • Ecological Niche: role played by the species in their community or a total set of environmental factors that determine the distribution of a species. • Generalist: has a wide range of tolerances for many factors • Brown rat • Specialist: have exacting habitat requirements, lower reproductive rates, and care for their young. • Giant Panda • Endemic: highly specialized to their habitat and do not exist anywhere else • Flora & Fauna on the Galapagos Islands

25. Speciation & Ecological Niches • Competition: fighting for the same resources • Competitive Exclusion Principle: no two species can occupy the same ecological niche for a long period of time. • The more efficient will survive, while the less will either find another habitat, die out, or experience a change in its behavior or physiology. • Resource Partitioning: several species can use different parts of the same resource and coexist.

26. Speciation & Diversity • Speciation: the development of a new species • Gradualism • Punctuated Equilibrium

27. Speciation & Diversity • How speciation occurs: • Geographic Isolation (Allopatric Speciation): species arise in separate geographic regions due to physical barriers causing reproductive isolation. • Behavioral Isolation (Sympatric Speciation):behaviors that cause reproductive isolation even though the organisms live in the same place.

28. Species Interactions • Competition: • Intraspecific Competition: competition within a species • Reducing competition: • Dispersal of young • Strong territoriality • Resource partitioning between generations • Young/adults feed differently • Interspecific Competition: competition among different species • The species living in the optimal range of their tolerance limits will have an advantage over a species living outside of their optimal range.

29. Species Interactions • Predator: any organism that feeds directly on any other living organism. • Predators: herbivores, carnivores, omnivores • NOT Predators: scavengers, detritivores, decomposers • Predator-mediated Competition: a superior competitor in a habitat will build up a larger population than its competing species; predators notice and increase hunting pressure of the superior species, reducing the superiors abundance, allowing the weaker species to increase its numbers.

30. Species Interactions • Predator-Prey Relationships can lead to co-evolution. • Co-evolution: when two interacting species evolve with each other because of their interactions. • Cheetah & Gazelle

31. Species Interactions • Mimicry • Batesian mimicry: harmless species look like poisonous or distasteful ones to scare of predators. • Mullerian mimicry: two harmful species look alike and predators learn to avoid both.

32. Species Interactions • Camouflage: Use of color, patterns, and form to blend in to the environment. • Helps prey hide from predators BUT • Also helps predators hide while lying in wait for their prey

33. Species Interactions Mutualism: relationship between two organisms benefit each other. Commensalism: one organism benefits, but the other organism in not affected. Parasitism: one organism benefits and the other organism is harmed.

34. Major Species Roles in an Ecosystem • Native species: • A species that normally lives and thrives in a particular ecosystem. • Nonnative (Invasive) Species: • A species that migrates to or is introduced (purposely or accidentally) into an ecosystem.

35. Major Species Roles in an Ecosystem • Indicator species: • Species that provide early warnings of damage to a community or an ecosystem. • Foundation species: • species that plays a major role in shaping their communities by creating and enhancing their habitats in ways that benefit other species.

36. Major Species Roles in Ecosystems • Keystone species: • A species who has a large influential impact on its community or ecosystem than its abundance would suggest. • Difference between a foundation species & keystone species • Foundation species help create habitats & ecosystems • Keystone species can do this, but also play and active role in maintaining an ecosystem and keep it functioning.

37. Properties of Ecosystems • Primary Productivity: Rate of biomass production (conversion of solar energy to chemical energy) • Energy left after respiration = net primary production

38. Properties of Ecosystems • Abundance: total number of organisms in a biological community. • Diversity: measure of the number of different species, ecological niches, or genetic variation present. • Abundance is usually inversely related to diversity • Diversity up, Abundance down • Diversity down, Abundance up • Generally diversity decreases but abundance within a species increases from the equator toward the poles.

39. Properties of Ecosystems • Ecological structure: patters of spatial distribution of individuals and populations within a community • Random • Live where resources are available • Uniform • Physical environment • Biological competition • Clustered • Protection • Mutual assistance • Reproduction • Access to resources

40. Properties of Ecosystems • Complexity: number of species at each trophic level and the number of tropic levels in a community. • Stability or Resiliency: • Constancy: lack of fluctuations in composition or function • Inertia: resistance to disturbances • Renewal: ability to repair damage after a disturbance • The more complex and interconnected an ecosystem, the more stable and resilient it is. • Many species in one trophic level, one can replace another • However, removal of a keystone species can greatly affect any system

41. Properties of Ecosystems • Edge Effects: change is species composition, physical environment or other ecologic properties between ecosystems • Sometimes sharp and distinct • Woodlands  grasslands • Gradual integration to from one to another • Ecotones: boundaries between adjacent communities • Sharply divided: closed community • Indistinctly divided: open communities

42. Changing Communities • Ecological succession: changes in an community as organisms occupy a site and the change the environmental conditions. • Primary Succession: land that is bare of soil and colonized by organisms where none lived before • Sandbar, mudslide, rockface, volcanic flow • Secondary Succession: existing community is disturbed and a new one develops from the disturbance • Wild fire, clear cut forests, urbanization • Successions occur by: • Modifying soil • Light levels • Food supplies • microclimate

43. Changing Communities • Terrestrial Primary Succession • Primary species: first colonists • Microbes, mosses, lichens (live off few resources) • When primary species die = organic matter = soil production • Seeds lodge in soil and grow • Succession progresses  more diversity

44. Changing Communities • Disturbances: anything that disrupts established patterns of species diversity and abundance, community structure, or community properties • Landslides, mudslides, hailstorms, tidal waves, tornadoes, volcanoes (natural) • Animal disturbances • elephants ripping down small trees • Agriculture, forestry, urbanization, dams, pipelines • Disturbance-adapted species: species that recover quickly from a disturbance

45. Extinction • Biological extinction: when a species can no longer be found anywhere on Earth • Forever • Irreversible • Weaken or even break an ecosystem • Can lead to secondary extinctions • Background extinction rate: the natural, low rate extinction of species • Extinction rate: percentage or number of species that go extinct within a determined period of time.

46. Mass Extinctions • The extinction of many species in a relatively short (geologically) period of time. • Fossil Records show that Earth has experienced at least 3 mass extinctions, where 50-95% of all species went extinct • Biodiversity has always returned to equal or higher levels, but required millions of years. • Causes are not well understood, but theories lead to environmental changes.

47. Mass Extinctions

48. Human Activities Leading to Extinction • Underlying Causes • Population growth • Rising resource use • Undervaluing natural capital • Poverty • Direct Causes • Habitat loss • Habitat degradation & fragmentation • Introduction of nonnative (invasive) species • Pollution • Climate change • Overfishing • Hunting & poaching • Sale of exotic pets/plants • Predator/pest control

49. HIPPCO Habitat destruction Invasive species Population Growth & Increasing resource use Pollution Climate Change Overexploitation

50. Endangered & Threatened Species • Endangered: so few of a species are living that they could soon become extinct • Sumatran tiger: < 60 • Mexican Gray Wolf: ~ 60 • California Condor: 172 • Whooping Crane: 210 Threatened: still has enough living members to survive short term but could easily become an endangered species.