Unit 1.1: Importance and Organization of Ecology

1. Unit 1.1: Importance and Organization of Ecology

2. Vocabulary Ecology: study of interactions between organisms and their environment Biodiversity: the total variety of living organisms in an ecosystem. Invasive species: Non-native species of plants or animals that out-compete native species in a specific habitat. Autotroph/Producer: auto-=self; troph- = feeder; organism that makes its own food through photosynthesis or chemosynthesis Heterotroph/Consumer: hetero-= different, other; organism that obtains energy by eating other organisms

3. Herbivore: organism that only eats producers; cows, deer, vegetarians… Carnivore: organism that only eats other consumers; lions, dogs, sharks, spiders… Omnivore: organism that eats both producers and consumers; pigs, raccoons, people… Detritivore: organism that feeds on dead organisms or waste; ex: worms, snails, dung beetles... Decomposer: breaks down organic matter; ex: fungi, bacteria Biomass: amount of living material

4. Guiding Questions for this unit: How does a change in biodiversity affect an ecosystem? What are five ways that humans affect biodiversity? How would eliminating the producers affect an ecosystem? How would eliminating the decomposers affect an ecosystem? What is the efficiency of energy transfer in a food chain and what happens to the energy that is not transferred?

5. Why Study Ecology? • Ecology: the study of how living organisms interact with each other and with their environment. • Interdependence: if you change one part of a system/ecosystem, it affects all other parts. • ex: Changing water temperature affects how algae grow, which affects plankton, which affects anchovies, which affects herring, etc...

6. Biodiversity: the total variety of living organisms in an ecosystem. • More biodiversity = greater stability • If you reduce the diversity of species, you lose valuable resources for the biosphere (and for humans) • Many species produce compounds that serve as food, medicine, or industrial products. • ex: rosy periwinkle only grows off African island, produces chemical used to treat cancer.

7. How Humans Affect Biodiversity • Five effects include: • Habitat Alteration: changing the area where organisms live • Examples of habitat alteration include: • Deforestation • Clearing land for farming • Habitat fragmentation: breaks land into smaller pieces • Creates biological “islands” • Fewer species can exist, more vulnerable to changes

8. Overhunting: • For meat, fur, hides • Some people believe animal body parts have medicinal properties • Pollution: introducing toxic compounds into food web • ex: DDT, a pesticide, is nonbiodegradable, and is stored in body tissues. • Biological magnification: when plants take in DDT, animals that eat plants concentrate that DDT b/c eat lots of plants. Animals that eat those plant-eaters consume even more DDT b/c can’t get rid of it

9. Introduce invasive species: • Non-native species out-compete native species for limited resources (food, water, space) • Often have no natural predators to control their population size • ex: pike introduced illegally into Lake Davis, overran trout/salmon population, threatens all down-stream habitats • Protect Endangered Species: • Humans also create “reserves” and other protected habitats to help preserve animals in danger of extinction.

11. Ecological Organization: 6 Levels • BBECPO: Big Bad Eagles Command Police Officers • Biosphere, (Biome,) Ecosystem, Community, Population, Organism • Biosphere – area on and around Earth where life exists • Broadest level – includes all organisms on Earth • Three parts of the biosphere: • Lithosphere: “litho-” = rock • Hydrosphere: “hydro-” = water • Atmosphere: “atmos-” = vapor

12. (Biome): Characterized by distinctive plant and animal species and a common climate • Five major biomes: • Aquatic: • Marine • Freshwater • Desert • Grassland • Tundra • Forest • Tropical: warm, near equator • Temperate: cooler, between ~30°-50° latitude • Boreal (taiga): cold, above 50° latitude

13. Ecosystem – all living organisms (biotic) andnonliving environmental components (abiotic) within a particular place • Abiotic – physical, chemical factors • Ex: salinity, sunlight, amount of oxygen available…

14. Community – all the members of different populations that live together in an area • Same as ecosystem, but excludes abiotic factors • Population– all the members of a single species living in the same area at the same time • Species: organisms that can interbreed to produce fertile offspring • Organism/Individual – single animal, plant, or cell • Simplest level

16. Energy Production • *Most energy for life comes from the Sun* • Autotrophs produce food: • ‘auto-’ = self; ‘troph-’ = feeder, so self-feeders, called “producers” • Use photosynthesis: convert energy from sunlightto produce food. • Plants, algae, cyanobacteria • Or chemosynthesis: using energy from chemicalsto produce food • Bacteria on ocean bottom - no sunlight so must use chemicals that spew from hydrothermal sea vents. • Or thermophiles next to volcanoes, hot springs

17. Heterotrophs consume food: • ‘hetero’ = other; ‘troph-’ = feeder, so feed on others, called “consumers” • Cannot make their own food, so get energy by consuming other organisms • All animals and fungi are heterotrophs! • Herbivore: eats only producers • Ex: deer, cow, vegetarians • Carnivore: eats only consumers • Ex: spiders, lions, dogs • Omnivore: eats both producers and consumers • Ex: humans, raccoons, bears, pigs • Detritivore: eats leftover remains of dead things • Ex: mushrooms, worms, flies

18. Producers = life • If no producers, then no food, no life! • Decomposers = life (almost) • Producers need minerals (nitrogen, phosphorus, magnesium) to make organic materials • Decomposers generate, recycle these minerals when breaking down dead, decaying matter • If no decomposers, then no minerals for plants to assimilate; (and lots of dead bodies just laying around!)

19. Feeding Relationships: • Food Chain: show a one-way flow of energy • Ex: grass  antelope  lion • Food Web: links many food chains • Shows more complex feeding relationships • Ex: mouse and rabbit both eat plants, and are eaten in turn by owls, jackals, etc…

20. Ecological Pyramids: • Trophic Levels: each step in a food chain/web • 1st level (bottom level): producers that convert solar energy into food • Plants, algae, phytoplankton, some bacteria • 2nd level: herbivores (and omnivores) that eat the producers • Primary (1°) consumers: deer, mice, zooplankton

21. 3rd level: carnivores (and omnivores) that eat herbivores • Secondary (2°) consumers • Usually smaller carnivores: raccoons, cats, spiders • 4th level: carnivores/omnivores that eat other carnivores • Tertiary (3°) consumers • Usually larger carnivores: lions, orcas, eagles • Detritivores/Decomposers exist at every level • Detritivores: consume dead organic matter (scavengers) • Decomposers: break down organic matter even further

22. Trophic Pyramids: show reductions between trophic levels • Energy Pyramids: show amount of energy that is transferred from one trophic level to the next • 90% of energy is lost at each level – why? • Some energy used to grow/build up body systems • Most energy is given off as heat during respiration • *Heat is lost, cannot be recycled!*

23. Biomass Pyramid: shows amount of living organic matter (biomass) at each trophic level Less biomass at each level – why? Less energy available so less biomass

24. Pyramid of Numbers: shows relative #’s of organisms at each trophic level Fewer organisms at the top of the pyramid b/c energy is limited Supply-and-demand: if more field mice, then more foxes b/c greater supply…

25. Warm-up answers for this unit: