Introduction to Ecology

1. Introduction to Ecology Chapter 18

2. Ecology Section 18.1

3. Definition: • The study of the interactions between organisms and their environment • Interdependence of organisms and their environment

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

5. Biosphere • The Earth & the atmosphere • “Thin film of life covering a lifeless planet”

6. Ecosystem • All organisms & nonliving environment in a given place • Organisms + water, pH, minerals, etc.

7. Community • All of the organisms in an ecosystem • Living things only!

8. Population • All the members of ONE species living in one place at one time

9. Organism • ONE member of ONE species living in one place at one time

10. Ecology of Organisms Section 18.2

11. Habitat • Where organisms live • Contains abiotic and biotic factors • Abiotic: nonliving components • Ex) sunlight, water, soil • Biotic: living components • Ex) plants, animals, predators

12. Tolerance Range • The range of abiotic conditions where the organism can still perform all activities for life

13. Acclimation • When an organism adjusts its tolerance to an abiotic factor • Ex) Moving from room to room with different temperatures

14. Control of Internal Conditions • Conformers:organisms that DO NOT regulate their internal environment • “cold blooded” • Regulators:organisms that DO regulate their internal environment • “warm blooded”

15. Escape from the Habitat • Dormancy:a state of reduced activity for the organism • Hibernation • Migration:movement of organism to a favorable habitat • Immigration: movement into a habitat • Emigration: movement out of a habitat

16. Niche • The way of life for a species • The role the species plays on its environment

17. Niche includes: • Tolerable conditions for organism • Methods to obtain resources • Number of offspring per year • Time of reproduction • Any other interactions with the environment • ETC.

18. 2 Types of Niches • Fundamental Niche:the range of conditions a species could POTENTIALLY tolerate and the range of resources it could POTENTIALLY use. • Realized Niche:the range of conditions and resources the species ACTUALLY tolerates and uses.

19. Questions: • Which niche is larger? • Why?

20. Niche Differences • A species’ niche can change within its lifespan • Generalist:species with a broad niche • Specialist:species with a narrow niche Specialist Generalist

21. Question: • Which type can adapt to a changing environment better? • Generalist or specialist? • Why?

22. 18-3 Energy Transfer Energy • Why do organisms need energy? • Maintain HOMEOSTASIS, growth, reproduction, etc. • How does energy affect an ecosystem? • Determines how many and what kind of organisms live in an ecosystem.

23. Energy Flow: • The sun is the ultimate source of energy • The PRODUCERSuse this energy to make “food” energy for themselves and for the CONSUMERS

24. Trophic Levels • The organism’s position in the sequence of energy transfers. • A.K.A. Trophic Level is a group of organisms whose feeding source is the same number of steps from the Sun.

25. Common Trophic Levels: • First = Producers (Autotrophs) • LARGEST • Second = Herbivores (Heterotrophs, Consumers) • Third and above = All other consumers (Heterotrophs, Omnivores, Carnivores, Decomposers) • SMALLEST

26. Omnivores (Humans) • Eat Plants & Animals • Detritivores (Scavengers) • Feed On Dead Plant & Animal Remains (buzzards) • Decomposers • Fungi & Bacteria

27. Consumers Heterotrophs eat other organisms to obtain energy. (e.g. animals) • Herbivores • Eat Only Plants • Carnivores • Eat Only Other Animals

28. Energy Gain by Trophic Levels: • At each trophic level, the energy stored in an organism is about 1/10 that of the level below it  (10%).

30. Implications on the ecosystem: • Because energy diminishes at each successive trophic level, few ecosystems can contain more than 4 or 5 trophic levels. • Organisms at higher levels (large carnivores) tend to be fewer in number than those at lower levels (producers).

31. Food Chain • A single pathway of feeding (and energy transfer) relationships among organisms in an ecosystem.

32. Ex) Food chain

33. Food Web • A diagram of the interrelated food chains in an ecosystem. • More accurate description of the ecosystem.

34. Can you now answer these questions? • Contrast between producers and consumers. • Explain the important role of decomposers in an ecosystem. • Explain why an ecosystem usually contains only a few trophic levels. • What is the difference between an organism’s niche and its habitat? • List 2 sources that add carbon to the carbon cycle.

35. Energy flows through an ecosystem and nutrients cycle in an ecosystem. Ecosystem Recycling (18.4)

36. Water Cycle Steps: • EVAPORATION from lakes, rivers, and oceans.  • TRANSPIRATION from plants and trees. • CONDENSATION – Cloud Formation • PRECIPITATION – Rain, Snow, Sleet, Hail. • RUN OFF, or RETURNED back into the Cycle. • Groundwater- water in soil or in underground formations of porous rock.

37. The Water Cycle

38. The Carbon Cycle • Cellular Respiration • Photosynthesis • Combustion • Death and decomposition

39. Human Influences • Atmospheric CO2 has risen more than 30% in the past 150 years. • Burning of fossil fuels- coal, oil, and natural gas • Burning down the tropical rain forest

40. The Nitrogen Cycle Nitrogen Fixation: the process of converting atmospheric nitrogen (N2) into nitrate, its useable form.

41. Key Terms Nitrogen-fixing bacteria: turn nitrogen gas into a useable form. Located in soil and the roots of some plants. Ammonification: bacteria decompose dead matter and release the nitrogen they contain as ammonia So… How do plants and animals get nitrogen?

42. Phosphorous Cycle • obtained by plants from water and soil, and animals from the food they eat • used to form bones, teeth, and molecules such as DNA and RNA • Source: erosion of rocks into the soil or water, decomposition of organisms, and fertilizers