Ecology

1. Ecology

2. What is Ecology • Ecology – the study of the interactions between organisms and the living and nonliving components of their environment.

3. Levels of Organization • Biosphere • Ecosystem • Community • Population • Organism

4. Levels of organization within an ecosystem • Organism – an individual living thing • Species – a group of organisms that can mate to produce fertile offspring

5. Population – all the members of the same species that live in the same place at the same time • Members of a population generally breed with one another rather than members of other populations

6. Community – a group of various species that live in the same place and interact with each other • Only made up of BIOTIC components

7. Defining an Ecosystem • Ecosystem – all of the organisms living in an area together with their physical environment • Ex. An oak forest, a coral reef, a mangrove swamp

8. Biosphere – the thin volume of Earth and its atmosphere that supports life.

9. Biotic and Abiotic • Biotic factors – the living and once living parts of an ecosystem • Plants and animals • Dead organisms • Abiotic factors – nonliving parts of an ecosystem • Air • Water • Rocks • Light • Temperature

13. Taxonomy and Ecology Review • What is taxonomy? Why bother to classify organisms? • What is the purpose of a scientific name? • What two taxa make up an organisms scientific name? How is this scientific name correctly written? • Write these scientific names correctly: • molamola • homo sapians • tyrannosaurus rex • What are the different taxonomic groups? What is the broadest, most inclusive? What is the smallest and most specific? • What is ecology? • What are the levels of organization in ecology from smallest to largest? • What is the difference between an ecosystem and a community? • What are biotic and abiotic factors?

14. Habitat • Habitat – the place an organism lives • Habitats have everything (biotic and abiotic) that the organism needs to survive • Organisms are well suited for their habitats • Very specific biotic and abiotic conditions

15. Organisms in a Changing Environment • Tolerance curve – a graph of performance vs. values of an environmental variable

16. Organisms in a Changing Environment • Acclimation – some organisms can adjust their tolerance to abiotic factors • Example – Goldfish • Organisms deal with changes in their environment in one of two ways: • Conformers – do not regulate their internal conditions, change as the environment changes • Regulators – use energy to control some of their internal conditions to keep them in an optimal range

17. Organisms in a Changing Environment • What happens when conditions are unfavorable? • Migration – movement to a more favorable habitat • Dormancy – a state of reduced activity during a period of unfavorable conditions

18. Niche • Niche – the specific role or way of life of a species within its environment • Often thought of as its “job” or what it does • Generalist species – have a broad niche; can tolerate a wide range of conditions and use a variety of resources • Specialist species – have a very narrow niche; have very specific dietary requirements, live in only specific conditions

19. Self Quiz • What are the main levels of organization in ecology? How do they differ? • What are biotic and abiotic ecosystem components? • What is a habitat? What is a niche? How do they differ? • What is a tolerance curve?

20. Producers and Consumers • Producer – an organism that makes its own food • Also called autotrophs • Example: Plants • Consumers – organisms that get their energy by eating other organisms • Also called heterotrophs • Example: Rabbits, Cows, Deer, Wolves

23. What eats what? • Herbivores – plant eaters • Carnivores – meat eaters • Omnivores – eat both plants and meat • Detritivores/decomposers - get their food by breaking down dead organisms

25. Productivity • Production - the synthesis and storage of organic molecules during the growth and reproduction of photosynthetic organisms • Gross primary productivity (GPP) – the rate at which producers in an ecosystem capture the energy of sunlight by producing organic compounds • (think photosynthesis) • Biomass – the organic material that has been produced in an ecosystem. Producers (plants) making organic molecules (like glucose!) • Net primary productivity (NPP) – the rate at which biomass accumulates in an ecosystem. • NPP = GPP - respiration

26. Estimated Annual Average NPP in Major Life Zones and Ecosystems

27. Food Chain • A linear sequence in which energy is transferred from one organism to the next as each organism eats another organism

28. Food Chain

29. Food Web • Shows many feeding relationships that are possible in an ecosystem. • Much more complex than a food chain

30. Food Web

32. Energy Transfer in an Ecosystem • Trophic level - each step in the transfer of energy through a food chain or food web in an ecosystem • Energy is lost each time energy is transferred from one organism to another

33. Trophic Levels • Only 10% of the energy is transferred from one trophic level to the next. • For every 1,000 producers, 1 tertiary consumer

34. Trophic Levels

35. Self Quiz • How does energy transfer through an ecosystem. Explain the number of higher level consumers that can be present? • What are autotrophs? Heterotrophs? • What is the difference between a food chain and a food web? • What is productivity?

36. Ecosystem Recycling • Biogeochemical cycles – the circulation of substances through living organisms from or to the environment • Water Cycle • Carbon Cycle • Nitrogen Cycle • Phosphorus Cycle

37. The Water Cycle

38. The Water Cycle • The water cycle involves • Evaporation • Condensation • Precipitation • Transpiration – the process by which water evaporates from the leaves of plants in terrestrial ecosystems

39. The Carbon Cycle • The process by which carbon is cycled between the atmosphere, land, water, and organisms.

40. The Carbon Cycle • Link between photosynthesis in producers and respiration in producers, consumers, and decomposers • Movement of carbon from the nonliving environment to living things and back.

41. The Carbon Cycle • Plants take in CO2 from the atmosphere through photosynthesis • Animals eat plants • Animals release CO2 through respiration • Some carbon may be converted into carbonates, which make up the hard parts of bones and shells • Deposit into carbon sinks • Over time, these become fossil fuels

43. Nitrogen Cycle • Nitrogen cycle - process in which nitrogen is cycled between the atmosphere, bacteria, and other organisms. • Nitrogen makes up 78% of atmosphere • Not in a form most organisms can use • Nitrogen fixing bacteria - fix atmospheric nitrogen into chemical compounds that organisms can use

44. Nitrogen Cycle

45. Nitrogen Cycle • Nitrogen-fixing bacteria live within nodules on the roots of plants called legumes • beans, peas, and clover • Plants that do not have nitrogen-fixing bacteria in their roots get nitrogen from the soil. • Animals get nitrogen by eating plants or other animals.

46. Nitrogen Cycle • Decomposers break down wastes and return the nitrogen that these wastes and dead organisms contain to the soil in a process called ammonification. • Nitrification – the process by which soil bacteria uptake ammonium and form it into nitrites • Denitrification – occurs when anaerobic bacteria break down nitrates and release nitrogen gas into the atmosphere.

48. Phosphorus Cycle • Phosphorus cycle – the movement of phosphorus from the environment to organisms and then back to the environment • Very slow cycle • No atmospheric component (Carbon and Nitrogen cycles do)

49. Phosphorus Cycle

50. Phosphorus Cycle • Rocks erode • Phosphate dissolves in water • Plants absorb phosphate through roots • Excreted when organisms decompose