Chapter 13: Principles of Ecology

1. Chapter 13: Principles of Ecology Honors Biology 2010-2011

2. What is Ecology? • Eco comes from Greek word “oikos” – house • -logy comes from “logos” – study of • Ecology means “study of the house” as coined by Ernst Haeckel • Ecology – the study of interactions among organisms (plants and animals) and their environment

3. Levels of Organization (page 397 Figure 13.2) • From individual to global: • Organism—individual living thing (ex. Lion)

4. Levels of Organization • Population—group of same species that live in one area (ex. Pride of lions)

5. Levels of Organization • Community—collection of interacting populations (ex. Lions, antelope, zebras, elephants, grasses, etc…)

6. Levels of Organization • Ecosystem—interactions of biotic and abiotic factors in an area • Biotic factors—living or once living things (ex. Animals, plants, microorganisms, etc…) • Abiotic factors—nonliving things (ex. Sunlight, temperature, soil, etc…)

8. Levels of Organization • Biome—regional or global community of organisms which is usually characterized by the climate conditions and plant communities that thrive there

9. Section 13.2 • In an ecosystem, each living thing depends on an array of biotic factors and abiotic factors in the ultimate web of life. • A single change in that web can lead to minor or major changes. • A keystone species is one that has an unusually large effect on its ecosystem. (ex. Beaver) (ex. Killing too many deer during hunting season)

10. Section 13.3 Energy in Ecosystems (page 406) • Autotrophs—“self feeder” • Heterotrophs—“different feeder” • Producers —obtain energy from the sun (by photosynthesis pg 407) or chemicals (by chemosynthesis pg 407) and convert it to a useable form of energy (like food, sugar, carbohydrates) • What kind of feeders are these?

11. Section 13.3 • *All ecosystems depend on producers, because they provide the basis for the ecosystem’s energy. • Consumers—get their energy by eating other living or once-living organisms (like autotrophs and/or other heterotrophs) • What kind of feeders are these?

12. Types of consumers: (page 409) • Herbivores—obtain energy from eating plants • Omnivores—obtain energy from eating plants and animals • Carnivores—obtain energy from eating animals

13. Types of Consumers • Detritivores—obtain energy from eating detritus or dead organic material (ex. Earthworm) • Decomposers—obtain energy from breaking down organic matter (dead) into simpler molecules that can be more easily absorbed by decomposers and by other organisms • Why would they by important? • Important in an ecosystem to return vital nutrients back into the environment

14. Section 13.4 Food Chains and Food Webs • To show energy transfer between different species, a food chain can be constructed. • A food chain is a linear sequence that links species by their feeding relationships. • Matter and energy move through an ecosystem by use of arrows • Example: autotroph→heterotroph→decomposer • *Heat energy is lost in each step

16. Trophic Levels • Trophic levels are the levels of nourishment in a food chain • Example: producer→herbivore→carnivore • Chain has 3 trophic levels

17. 1sttrophic level  producer (base) • 2ndtrophic level  primary (1’) consumer (herbivore), first order • 3rdtrophic level  secondary (2’) consumer (omnivore/carnivore), second order • 4thtrophic level  tertiary (3’) consumer (omnivore/ mostly carnivore), third order (top level) • Energy flows through an ecosystem in ONE direction

18. Food web- links all the food chains in an ecosystem • The stability of any food web depends on the presence of producers, as they form the base of the food web

20. Section 13.6 Pyramid Models • Each level in the food chain contains much less energy than the level below it. The sun continually pumps new energy into the system to continue life. • Only about 10% of the available energy is transferred to the next trophic level. Maximum number of organisms in a food chain is 5 because of energy loss. • Where does the rest of the energy go?

22. An energy pyramid compares energy used by producers, primary consumers, and other trophic levels (in units of kilocalories, kcal) see figure 13.17 on page 418 • A biomass pyramid provides a picture of the mass of producers needed to support primary consumers, the mass of primary consumers required to support secondary consumers, and so on.  • A pyramid of numbers shows the numbers of individual organisms at each trophic level in an ecosystem. • Biomass pyramids and pyramids of numbers may occur in an inverted, or upside down formation. What might this indicate about that ecosystem?