Introduction to Ecology Chapter 18

1. Introduction to EcologyChapter 18 Essential Question What is ecology?

2. Standards • B-6.1 Explain how the interrelationships among organisms (including predation, competition, parasitism, mutualism, and commensalism) generate stability within ecosystems. • B-6.2 Explain how populations are affected by limiting factors (including density-dependent, density-independent, abiotic, and biotic factors). • B-6.3 Illustrate the processes of succession in ecosystems. • B-6.4 Exemplify the role of organisms in the geochemical cycles (including the cycles of carbon, nitrogen, and water). • B-6.5 Explain how ecosystems maintain themselves through naturally occurring processes (including maintaining the quality of the atmosphere, generating soils, controlling the hydrologic cycle, disposing of wastes, and recycling nutrients). • B-6.6 Explain how human activities (including population growth, technology, and consumption of resources) affect the physical and chemical cycles and processes of Earth.

3. What is Ecology? • Ecology is the study of the interactions between organisms and the living and nonliving components of their environment. • It involves collecting information about organisms and their environments, looking for patterns, and seeking to explain these patterns. • The field of ecology was named in 1866.

4. Interdependence : Key Theme • Quality of interconnectedness or interdependence of organisms and how they interact with biotic (living portion) and abiotic (nonliving portion) of their environment • All organisms interact with other organisms their surroundings (biotic factors) and with the nonliving portion of their environment (abiotic factors such as temperature) • Example – we depend on the oxygen and carbohydrates that plants produce and plants depend on the carbon dioxide that we give off

5. Effects of Interdependence • Consequence of interdependence is that any change in the environment can spread through the network if interaction and affect organisms that appear to be far removed from the change • Example: figure 18-1 • plentiful crop of acorns helps support a large deer and mice population  deer and mice help support a large population of ticks  increase in Lyme disease (carried by deer ticks)to humans who visit the forest • Result: after a season of high acorn production, the cases of Lyme disease increase.

6. Why is ecology important? • Over the past few decades, humans have changed the environment on a greater scale than ever before in our history. • Learning how to improve our effect on the environment is critical to the survival of our species. • While the human population has increased…the other species numbers have declined and some have become extinct. • Currently, species are disappearing faster than at any time since the last mass extinction of the dinosaurs 65 million years ago! • There have been five prior mass extinctions in the past. We are in the 6th mass extinction now. • Reasons: habitat destruction, over hunting, and increased diseases and predators.

7. What are we doing to our environment? • Hole in ozone layer caused by CFC’s • Climatic changes caused by increased CO2 in atmosphere • Increased populations and decrease in our natural resources • Pollution affecting quality of air we breath • All of these factors affect the physical and chemical cycles and processes of the earth

8. Section 1 Introduction to Ecology Chapter 18 Levels of Organization

10. What is an ecosystem? • Biosphere is composed of smaller units called ecosystems • Ecosystem is a community of organisms and their abiotic (nonliving) environment • Organisms interact in ways that affect their survival • Example: pond ecosystem contains chemical and physical aspects (abiotic) that influence its inhabitants • Chemical composition of the pond- its pH, levels of dissolved oxygen and carbon dioxide, and its supply of nitrogen– helps to determine what kinds of organisms live in the pond and how abundant they are • An important physical factor is how much sunlight the pond receives.

11. Ecosystem components • Biotic factors – all of living things that affect organisms • Abiotic factors – all of the physical and chemical characteristics (nonliving factors) of the environment • Abiotic factors include temperature, humidity, pH, salinity, oxygen concentration, amount of sunlight, availability of nitrogen, and precipitation • Abiotic factors are not constant – vary from place to place and over time

12. Organisms in a Changing Environment • Each organism is able to survive within a limited range of environmental conditions • Organisms can not survive outside of conditions that fall outside its tolerance limits • Range may be determined by levels of factors such as pH, temperature, or salinity. • Organisms can control their changes by regulating their response to their environment – cold blood animals vs. warm blooded animals • Some animals can survive unfavorable conditions by escaping from them – dormancy, migration, being active when temperatures are favorable

13. The Niche • Species do not occupy or use all parts of their habitat at once. • specific role, or way of life, of a species within it environment is called its niche. • includes the range of conditions that the species can tolerate • resources it uses • methods by which it obtains resources • number of offspring it has • its time of reproduction • all other interactions with its environment.

14. Energy Transfer • All organisms need to carry out essential functions such as growth, movement, maintenance and repair, and reproduction • energy flows from the sun  autotrophs  consumers. • Amount of energy in ecosystem receives and amount of energy that is transferred from one organism to another affects the structure of the ecosystem • The interrelationships between organisms generate stability in an ecosystem

15. Food Chains and Food Webs • Food chain – single pathway of feeding relationships among organisms in ecosystem that results in energy transfer • Food web – interrelated food chains in a ecosystem • Trophic levels are feeding levels • Limitations of trophic levels - only about 10% of energy available at one trophic level is transferred to next level -- low rate of energy transfer between each level accounts for few levels and less organisms at each level

16. Section 3 Energy Transfer Chapter 18 Food Chain in an Antarctic Ecosystem

17. Section 3 Energy Transfer Food Web in an Antarctic Ecosystem

18. Section 3 Energy Transfer Chapter 18 Energy Transfer Through Trophic Levels

19. Limiting Factors in Environment • Biotic factors – living factors such as interrelationships among organisms (predation, competition, parasitism, mutualism, and commensalism) • Abioticfactors – nonliving factors such as temperature and air quality • Density dependent factors - include shortages of food or nesting sites and are triggered by increasing population density • Density independent factors - include weather, flood, and fires reduce population size • These factors limit the how populations form and also generate stability within an ecosystem.

20. Biogeochemical Cycles • As energy flows through an ecosystem, matter must be recycled and reused • Substances such as water, carbon, nitrogen, calcium, and phosphorus each pass between the living and nonliving worlds through biogeochemical cycles

21. Section 4 Ecosystem Recycling Chapter 18 Water Cycle

22. Section 4 Ecosystem Recycling Chapter 18 Carbon Cycle

23. Section 4 Ecosystem Recycling Chapter 18 Nitrogen Cycle

24. Phosphorus Cycle

25. Chapter 18 Standardized Test Prep Multiple Choice 1. What are the levels of organization in ecology? A. cell, tissue, organ, organ system, body B. organ, organism, population, community C. organism, population, community, ecosystem, biosphere D. population, habitat, ecosystem, biogeochemical system, planet

26. Chapter 18 Standardized Test Prep Multiple Choice 1. What are the levels of organization in ecology? A. cell, tissue, organ, organ system, body B. organ, organism, population, community C. organism, population, community, ecosystem, biosphere D. population, habitat, ecosystem, biogeochemical system, planet

27. Chapter 18 Standardized Test Prep Multiple Choice 2. What makes up an ecosystem? A. all the habitat types on Earth B. all parts of Earth where life exists C. all members of a species in the same area D. all the living and nonliving factors in an environment

28. Chapter 18 Standardized Test Prep Multiple Choice 2. What makes up an ecosystem? A. all the habitat types on Earth B. all parts of Earth where life exists C. all members of a species in the same area D. all the living and nonliving factors in an environment

29. 3. Which of the following are abiotic factors? A. plants B. animals C. sunlight D. microorganisms

30. 3. Which of the following are abiotic factors? A. plants B. animals C. sunlight D. microorganisms

31. 5. Which organisms are most critical in the nitrogen cycle? A. plants B. nitrates C. animals D. bacteria

32. 5. Which organisms are most critical in the nitrogen cycle? A. plants B. nitrates C. animals D. bacteria

33. Chapter 18 Standardized Test Prep Multiple Choice,continued Use the illustration below to answer question 6. The illustration represents a trophic pyramid.

34. Chapter 18 Standardized Test Prep Multiple Choice, continued 6. What is the term for the kinds of organisms that make up the trophic level labeled C? A. producers B. consumers C. detritivores D. decomposers

35. Chapter 18 Standardized Test Prep Multiple Choice, continued 6. What is the term for the kinds of organisms that make up the trophic level labeled C? A. producers B. consumers C. detritivores D. decomposers

36. Chapter 18 Standardized Test Prep Multiple Choice, continued 6. What is the term for the kinds of organisms that make up the trophic level labeled C? A. producers B. consumers C. detritivores D. decomposers

37. Chapter 18 Standardized Test Prep Multiple Choice, continued 4. How do decomposers benefit an ecosystem? A. by returning nutrients to the soil B. by manufacturing energy from sunlight C. by removing excess nutrients from the soil D. by removing predators from the ecosystem

38. Chapter 18 Standardized Test Prep Multiple Choice, continued 4. How do decomposers benefit an ecosystem? A. by returning nutrients to the soil B. by manufacturing energy from sunlight C. by removing excess nutrients from the soil D. by removing predators from the ecosystem

39. Chapter 18 Standardized Test Prep Multiple Choice,continued Use the illustration to answer question 8. The illustration represents a food chain.

40. Chapter 18 Standardized Test Prep Multiple Choice, continued 8. What role do the krill have in this food chain? A. They are producers. B. They are consumers. C. They are detritivores. D. They are decomposers.

41. Chapter 18 Standardized Test Prep Multiple Choice, continued 8. What role do the krill have in this food chain? F. They are producers. B. They are consumers. H. They are detritivores. J. They are decomposers.