Chapter 1

Question 1

What is ecology?

Answer 1

the scientific study of the abundance and distribution of organisms in relation to other organisms and environmental conditions.

Question 2

Ecological systems

Answer 2

Biological entities that have their own internal processes and interact with their external surroundings

Question 3

Individuals

Answer 3

the most fundamental unit of ecology.

Individuals acquire nutrients and energy,
and produce waste.

Individuals have a membrane boundary that separates internal processes from the external environment.

Question 4

Populations

Answer 4

individuals of the same species living in a particular area.

Geographic range (distribution) is the extent of land or water within which a population lives.

Abundance is the total number of individuals.

Density is the number of individuals per unit area.

Composition is the makeup in terms of age, gender, or genetics.

Question 5

Communities

Answer 5

Populations of species living together in a particular area.

Includes many types of interactions, such as predation and competition.

Question 6

Ecosystems

Answer 6

one or more communities of living organisms interacting with their nonliving physical and chemical environments.

Research is focused on movement of energy and matter between physical and biological components.

This includes the “flow” of material from “pools” of elements, such as carbon, oxygen, hydrogen, nitrogen, and phosphorus.

Question 7

The biosphere

Answer 7

all ecosystems on Earth.

Distant ecosystems are linked together by exchanges of wind and water and by the movement of organisms.

Question 8

Individual approach

Answer 8

Understands how adaptations, or characteristics of an individual’s morphology, physiology, and behavior enable it to survive in an environment.

Question 9

Population approach

Answer 9

Examines variation in the number, density, and composition of individuals over time and space.

Question 10

Community approach

Answer 10

Understands the diversity and interactions of organisms living together in the same place.

Question 11

Ecosystem approach

Answer 11

Describes the storage and transfer of energy and matter.

Question 12

Biosphere approach

Answer 12

Examines movements of energy and chemicals over the Earth’s surface.

Question 13

Evolution

Answer 13

a change in the genetic composition of a population over time.

Question 14

Natural selection

Answer 14

A change in the frequency of genes in a population through differential survival and reproduction of individuals that possess certain phenotypes.

Three requirements

1. Individuals vary in their traits.
2. Traits are heritable.
3. Variation in traits causes some individuals to experience higher fitness (survival and reproduction).

Question 15

prokaryotes

Answer 15

First organisms without distinct organelles.

Can utilize sources of energy that most other organisms cannot, such as N2 and H2S gas.

Question 16

Protists

Answer 16

Eukaryotes that include protozoa, some algae, and slime molds.

Some protists can grow very large and look like large plants (e.g., kelp).

Question 17

fungi

Answer 17

have hyphae that extract nutrients from dead or living tissues.

They secrete acids, and enzymes digest food externally.
Many are decomposers and many are plant mutualists.

Question 18

Producers

Answer 18

or autotrophs—convert chemical energy into resources.

Question 19

Consumers

Answer 19

or heterotrophs—obtain their energy from other organisms.

Question 20

Mixotrophs

Answer 20

can switch between being producers and consumers.

Question 21

Detritivores

Answer 21

break down dead organic matter (i.e., detritus) into smaller particles.

Question 22

Decomposers

Answer 22

break down detritus into simpler elements that can be recycled.

Question 23

Predation

Answer 23

when an organism kills and consumes an individual.

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Question 24

Parasitism

Answer 24

when one organisms lives in or on another organism.

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Question 25

Herbivory

Answer 25

when one organism consumes producers.

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Question 26

Competition

Answer 26

when two organisms that depend on the same resource have a negative effect on each other.
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Question 27

Mutualism

Answer 27

when two species benefit from each other.

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Question 28

Commensalism

Answer 28

when two species live in close association and one receives a benefit, whereas the other is unaffected.
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Question 29

Habitat

Answer 29

The place, or physical setting, where an organism lives. Distinguished by physical features, such as dominant plant type.

Question 30

Niche

Answer 30

the range of abiotic and biotic conditions an organism can tolerate.

Example: Different insects prefer to feed on different crop species that may be growing in the same field.

Question 31

Hypotheses

Answer 31

ideas that potentially explain a repeated observation.

Question 32

Proximate hypotheses

Answer 32

address the cause of immediate changes in individual phenotypes or interactions.

Question 33

Ultimate hypotheses

Answer 33

address the fitness costs and benefits of a response.

Question 34

Randomization

Answer 34

a requirement for manipulation experiments; every experimental unit must have an equal chance of being assigned to a particular treatment.

Question 35

Mathematical models

Answer 35

representations of a system with a set of equations that correspond to hypothesized relationships among the system’s components.

Ecologists often test mathematic models using natural or manipulative experiments.

Question 36

Greenhouse gases

Answer 36

compounds in the atmosphere that absorb infrared heat energy emitted by Earth and then emit some of the energy back toward Earth. High amounts of these gases can increase average Earth temperatures.