How Living Things Interact T - blogs.4j.lane.edu

Chapter

How Living Things Interact

The two tree swallows in the photo are clearly communicating. Communication between two members of a species is just one way that living things interact. Perhaps the birds are "arguing" over which one of them gets the nesting box. Providing nesting boxes is a way that humans, a different species, interact with tree swallows. In Chapter 3, you will learn about different ways that living things interact in ecosystems. You will also find out how these interactions can cause changes in ecosystems.

Organize Your Thoughts

Interactions

Species interactions

? Competition ? Cooperation ? Symbiosis

Ecology

Energy

? Food web ? Energy pyramid

Goals for Learning

To define ecology and identify biotic and abiotic factors To describe the parts of an ecosystem To identify the roles of producers, consumers, and decomposers To describe food chains and food webs To define niche, habitat, and predator-prey relationships To explain succession and how ecosystems change over time

Lesson

Everything Is Connected

Objectives

After reading this lesson, you should be able to + define ecology + describe how

biotic and abiotic factors interact

Ban To forbid by law Ecology

The interactions among living things anil the nonliving things in their environment

Ecologist

A scientist who studies ecology

In the 1960s, scientists noticed that the numbers of peregrine falcons were declining. After years of research, they discovered the cause: a chemical pesticide called DDT. DDT helped farmers by killing the insects that fed on their crops. However, when birds ate dead insects that contained DDT, the chemical poisoned them. When peregrine falcons ate these poisoned birds, they got even more DDT. DDT did not kill adult falcons. Instead, DDT caused females to lay eggs with weak shells. The weight of the parent crushed the eggs, and the chicks died.

Eventually, DDT was banned, and peregrine falcon populations started to recover. It turned out that DDT hurt many living things, includinghoneybees, bald eagles, and even people. It took scientists years to discover the connections between DDT and the problems it caused. This is because it is often difficult to know how different environmental factors interact.

The Study of Interactions

The word ecology was first used by a German biologist in 1869. It comes from two Greek words: eco, meaning house, and logy, meaning study. Ecology, then, is the study of interactions between organisms and their "house"--their environment. By studying these interactions,ecologists can learn what organisms need to survive.They can also learn how organisms affect other living things and the environment.

Technology and Society

Scientists can reduce the need for pesticides by changing the DMA of some crops. For example, corn containing genes from the bacterium Bacillus thuringiensis has been created in a lab. This corn, called Bt corn, produces a chemical that kills a common pest called the corn borer.

82 Chapter 3 How Living Things Interact

Biotic factor

A living part of the environment

Abiotic factor

A nonliving part of the environment

Microorganism

An organism too small to be seen without being magnified

Domain

The highest level of classification of living things

Kingdom

The second level of classification of living things

Rnvironniental si-iciuc is one b r a n c h of ecology. Environmental scientists focus mostly on the interactions between humans and the environment. They study what humans need to survive and their effects on their environment.

For example, when farmers used DDT, they did not know it harmed more than pests. Scientific studies were needed to discover what other damage DDT was causing.That is one of the reasons environmental science is so important. It helps people learn how to prevent harmful changes to the environment.

Biotic Factors Geologists divide everythingthat makes up the earth into biotic factors and abiotic factors. The living parts of the earth are called the biotic factors. These include all the different types of life, such as animals, plants, fungi, and microorganisms. Microorganisms are living things too small to be seen without being magnified. The biotic factors in an environment also include the wastes organisms produce.

All of these types of living things are made up of cells. Some organisms, like yeast, are made up of a single cell. Other organisms, like humans, can be made up of trillions of cells.

Biotic factors are divided into a number of categories, beginning with domains and kingdoms. A domain is the highest level of classification, or organi/ation, of living things. The three domains are Bacteria, Archaea, and Eukarya. A kingdom is the second level of classification. Most living things are included in Kingdom Protista, Kingdom Fungi, Kingdom Plantae, or Kingdom Animalia. These kingdoms arc located within Domain Eukarya.

After being placed in a kingdom, organisms are organized by phylum (for animals) or division (for plants and fungi). The next levels of classification are class, order, family, genus, and species. Assigning organisms to these different levels of classification is one way to identify them. This is important for many types of scientific research.

How Living Things Interact (Chapter 3 83

Mineral

An element or combination of dements found in the earth

Research and Write

Identify one organism from each domain of life. Then use the Internet to find out in which kingdom these organisms are classified. For each organism, write the domain name, the kingdom name, and the organism name.

Abiotic Factors

The nonliving parts of an ecosystem are called abiotic factors. These include rocks, minerals, water, air, sunlight, wind, and temperature. A mineral is an element or combination of elements found in the earth. These examples of abiotic factors contain no living material. Some abiotic factors were once alive, like leather or wood used for building. They still contain cells that are no longer alive.

Living things depend on the nonliving parts of the environment. They also depend on other living things. Every time you take a breath, you are interactingwith the atmosphere. When you eat an apple, you are interactingwith plants. When you take a drink, you are interacting with water systems. These are just a few examples of how biotic and abiotic factors are connected.

Express Lab 3

Materials *? aquarium with fish * pencil * paper

Procedure 1. Observe the fish tank in

your classroom. 2. Draw all the parts of the

fish's environment.

3. Label each item as biotic or abiotic.

Analysis

1. What are some ways that the abiotic factors in the fish's environment affect the biotic factors?

2. Describe the environment of the fish in terms of the atmosphere, lithosphere, and hydrosphere.

84 Chapter 3 How Living Things Interact

Word Bank

abiotic biotic

ecology

Lesson 7 R E V I E W

On a sheet of paper, write the word from the Word Bank that completes each sentence correctly.

1. Environmental science is one branch of

.

2. Leather and wood are _____ factors that have cells.

3. The different kinds of life are part of the an environment.

factors in

On a sheet of paper, write the letter of the answer that completes each sentence correctly.

4.

is a pesticide that caused serious problems for birds,

insects, and people.

A DDT B Carbon C Iron D Chlorophyll

5. Examples of biotic factors in an ecosystem include

.

A butterflies and rocks B water and sunlight

C squirrels and fungi D weather and grass

6. Examples of abiotic factors in an ecosystem include

.

A sunlight and minerals C flowers and leaves B microorganisms and soil D rocks and moss

Critical Thinking On a sheet of paper, write the answers to the following questions. Use complete sentences.

7. Give an example of how organisms depend on nonliving parts of an ecosystem.

8. Explain how DDT caused the numbers of peregrine falcons to decline. What caused their numbers to rise again?

9. Describe how ecology can help protect organisms and their environments.

10. List three abiotic factors and three biotic factors in an ecosystem where you live.

How Living Things Interact Chapter 3 85

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