Chapter: Ecology

2. Table of Contents Chapter: Ecology Section 1: What is an ecosystem? Section 2: Relationships Among Living Things Section 3: Energy Through the Ecosystem

3. What is an ecosystem? • Organisms, along with the nonliving things in the woods or yard, such as soil, air, and light, make an ecosystem (EE koh sihs tum). 1 Ecosystems • An ecosystem is made up of organisms interacting with one another and with nonliving factors to form a working unit.

4. What is an ecosystem? 1 The Study of Ecosystems • Ecology is the study of the interactions that take place among the living organisms and nonliving parts of an ecosystem. • Ecologists spend a lot of time outdoors, observing their subject matter up close.

5. What is an ecosystem? 1 The Study of Ecosystems • Like other scientist, ecologists also conduct experiments in laboratories. • But, most of the ecologist's work is done in the field.

6. What is an ecosystem? 1 The Largest Ecosystem • The biosphere(BI uh sfihr) is the largest ecosystem on Earth. • The biosphere is the part of Earth where organism can live.

7. What is an ecosystem? 1 The Largest Ecosystem • It includes the topmost layer of Earth's crust; all the oceans, rivers, and lakes; and the surrounding atmosphere. • The biosphere is made up of all the ecosystems on Earth combined.

8. What is an ecosystem? 1 Living Parts of Ecosystems • Each of the many ecosystems in the biosphere contains many different living organisms. • The organisms that make up the living part of an ecosystem are called biotic factors. • An organisms depends on other biotic (bi AH tihk) factors for food, shelter, protection, and reproduction.

9. What is an ecosystem? 1 Nonliving Parts of Ecosystems • The nonliving things found in an ecosystem are called abiotic (ay bi AH tihk) factors. • Abiotic factors affect the type and number of organisms living in ecosystems.

10. What is an ecosystem? 1 Soil • One abiotic factor that can affect which plants and other organisms are found in an ecosystem is soil. • Soil is made up of a combination of minerals, water, air, and organic matter—the decaying parts of plants and animals.

11. What is an ecosystem? 1 Soil • Different amounts of minerals, organic matter, water, and air make different types of soil. Click image to view movie.

12. What is an ecosystem? 1 Temperature • Temperature also determines which organisms live in a particular place.

13. What is an ecosystem? 1 Water • Another important abiotic factor is water. • Some organisms, such as fish, whales, and algae (AL jee), are adapted for life in water, not on land. • But these organisms depend upon water for more than just a home.

14. What is an ecosystem? 1 Water • Water helps all living things carry out important life processes such as digestion and waste removal. • In fact, the bodies of most organisms are made up mostly of water. • Scientists estimate that two-thirds of the weight of the human body is water.

15. What is an ecosystem? 1 Water • The amount of water available in an ecosystem can determine how many organisms can live in a particular area. • It can also serve as shelter and as a way to move from place to place.

16. What is an ecosystem? 1 Sunlight • The Sun is the main source of energy for most organisms on Earth. • Energy from the Sun is used by green plants to produce food. • When you eat food produced by a plant, you are consuming energy that started out as sunlight.

17. What is an ecosystem? 1 A Balanced System • Every ecosystem is made up of many different biotic and abiotic factors working together. • When these factors are in balance, the system is in balance, too. • Many events can affect the balance of a system. • One example would be a long period of time without rain (called a drought).

18. Section Check 1 Question 1 An aquarium of turtles can be considered a small ecosystem. Which of the following is an example of how the turtles could interact with an abiotic part of the aquarium ecosystem? A. turtles eat insects you place in the aquarium B. turtles fight each other for food C. turtles move onto rocks heated by sunlight D. turtles pull into their shells when you startle them

19. Section Check 1 Answer The correct answer is C. Sunlight is an abiotic factor. When turtles warm themselves in the sunlight, they are interacting with this nonliving part of the ecosystem.

20. Section Check 1 Question 2 What is the largest ecosystem on Earth? Answer The biosphere is the largest ecosystem on Earth. It is the part of Earth where organisms can live and includes parts of Earth’s crust, waters, and atmosphere.

21. Section Check 1 Question 3 Which represents the weight of the human body that is made up of water? A. 1/4 B. 1/3 C. 1/2 D. 2/3

22. Section Check 1 Answer The correct answer is D. Scientists estimate that two-thirds of the weight of the human body is water.

23. Relationships Among Living Things 2 Organizing Ecosystems • When ecologists study living things, they usually don't start by studying the entire biosphere. • To separate the biosphere into smaller systems that are easier to study, ecologists find it helpful to organize living things into groups.

24. Relationships Among Living Things 2 Groups of Organisms • A population is a group of the same type of organisms living in the same place at the same time. • Some populations that you might find in a coral reef ecosystem are sponges, algae, sharks, and coral.

25. Relationships Among Living Things 2 Groups of Populations • All of the populations that live in an area make up a community (kuh MYEW nuh tee). • The members of a community depend on each other for food, shelter, and other needs.

26. Relationships Among Living Things 2 Characteristics of Populations • Ecologists ask questions to describe populations. • They want to know the size of the population, where it members live, and how it is able to stay alive.

27. Relationships Among Living Things 2 Population Density • Ecologists determine population density (DEN suh tee) by comparing the size of a population with its area. • For instance, if 100 dandelions are growing in a field that is one square kilometer in size, then the population density is 100 dandelions per square kilometer.

28. Relationships Among Living Things 2 Studying Populations • To study migrating monarchs, a "monarch watcher"—often a school student like yourself—carefully catches a monarch and attaches a tag to one of its wings. • Later, someone else who catches the same butterfly can use the tag to figure out how far the butterfly has flown.

29. Relationships Among Living Things 2 Studying Populations • Information from many butterflies can be combined to build a picture of the monarch's migration. • Similar techniques are used to study populations of birds, wolves, and other animals that travel long distances.

30. Relationships Among Living Things 2 Limits to Populations • Populations cannot grow larger and larger forever. • The things that limit the size of a population, such as the amount of rainfall or food, are called limiting factors.

31. Relationships Among Living Things 2 Limits to Populations • One biotic limiting factor in stream ecosystem is the mosquito population. • Frogs eat mosquitoes. • If lack of rain caused the mosquito population to go down, then the frog population might not have enough food and its population size might also decline.

32. Relationships Among Living Things 2 Interactions in Communities • Feeding interactions are the most common interactions among organisms in a community. • The greater the population size of an area, the greater the competition for resources such as food.

33. Relationships Among Living Things 2 Interactions in Communities • One of the most common ways organisms interact in a community is by being food for another organism.

34. Relationships Among Living Things 2 Interactions in Communities • Organisms will compete for any resource that is in limited supply. • Space, water, sunlight, and shelter are all resources that may be limited in a particular ecosystem.

35. Relationships Among Living Things 2 Eat or Be Eaten • A falcon is a bird of prey, which means it captures and eats other animals. • The falcon is a predator (PRE duh tur). • Predation (pre DAY shun) is the act of one organism feeding on another.

36. Relationships Among Living Things 2 Organisms That Live Together • There are other types of relationships among organisms. • In one type of interaction, both organisms in the relationship benefit.

37. Relationships Among Living Things 2 Organisms That Live Together • In another type of relationship, only one organism benefits. • The other organism doesn't benefit, but it is not harmed. • A bird building a nest in a tree is an example of this. • The bird gets protection from the tree, but the tree isn't harmed.

38. Relationships Among Living Things 2 Organisms That Live Together • In still another relationship, one organism is helped while the other is harmed. • Have you ever been bitten by a mosquito? • That's a firsthand experience of this type of relationship.

39. Relationships Among Living Things 2 Where and How Organisms Live • The role of an organism in an ecosystem is called the organism's niche (NICH). • What do you think the role of the fish might be in an aquarium ecosystem? • The niche of the fish includes adding nutrients to the ecosystem through its waste products that encourage the growth of algae.

40. Relationships Among Living Things • The place where an organisms lives is called its habitat (HA buh tat). 2 Where and How Organisms Live • Different species of organisms often live in the same habitat.

41. Relationships Among Living Things • Resources, such as food, living space, and shelter, are shared among all the species living in a habitat. 2 Where and How Organisms Live • Each species has a different niche within the same habitat.

42. Section Check 2 Question 1 Which represents a population? A. flock of birds that includes pigeons, sparrows, and doves B. forest of trees and all the birds that live in them C. group of elephants in Africa and another group in India D. group of gray squirrels that live in a park together

43. Section Check 2 Answer The correct answer is D. A population is a group of the same type of organisms living in the same place at the same time.

44. Section Check What type of information would you need to collect concerning the monarch butterfly population in order to prepare a map like this one showing themigration of monarchs? 2 Question 2

45. Section Check 2 • How long • butterflies live • B. what foods • butterflies eat • C. when butterflies • fly through • certain areas • D. when butterflies • lay their eggs

46. Section Check 2 Answer The correct answer is C. A Butterfly can be captured and tagged to indicate where it was caught. When the same butterfly is captured later, the tag can be used to figure out how far the butterfly has flown.

47. Section Check 2 Question 3 What is the difference between an organism’s niche and its habitat? Answer A niche is the role of an organism in an ecosystem; like how it obtains food. An organism’s habitat is where it lives.

48. Energy Through the Ecosystem 3 It’s All About Food • Energy moves through an ecosystem in the form of food. • In any community, energy flows from producers to consumers.

49. Energy Through the Ecosystem 3 Producers and Consumers • An organism that makes its own food, like a plant, is called a producer. • The grasshopper that nibbles on the plants is a consumer. • A consumer eats other organisms.

50. Energy Through the Ecosystem 3 Decomposers • Some of the consumers in an ecosystem are so small that you might not notice them, but they have an important role to play. • Decomposers use dead organisms and the waste material of other organisms for food.