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Question 1

What is Earth’s major surface feature?

Answer 1

Oceans, which cover most of the Earth

Question 2

What do we call the water that covers most of Earth?

Answer 2

Salty water solution, known as oceans

Question 3

What types of organisms live in the oceans?

Answer 3

From microscopic organisms to the largest animals, such as whales

Question 4

Can organisms that live in salt water also survive in fresh water?

Answer 4

Some can, but most cannot; each is adapted to its own environment

Question 5

What are the key concepts covered in this section?

Answer 5

• Water quality
• Adaptations to aquatic ecosystems
• Human impact

Question 6

What will you be able to describe after completing this section?

Answer 6

The diversity of organisms in salt and freshwater systems

Question 7

What common characteristics allow species to live in water?

Answer 7

Adaptations specific to aquatic environments

Question 8

What factors contribute to the development of adaptations in aquatic species?

Answer 8

Environmental factors such as temperature, light, pressure, and salinity

Question 9

What is an ecosystem?

Answer 9

Any place where living things interact with other living and nonliving things

Question 10

Which ecosystems are the most diverse in the world?

Answer 10

• Tropical rain forests
• Coral reefs

Question 11

What does diversity in an ecosystem refer to?

Answer 11

The variety of different kinds of species living there

Question 12

Why is a diverse ecosystem an indicator of a healthy environment?

Answer 12

More species indicate greater availability of nutrients, light, and oxygen

Question 13

What is the upper zone of a lake characterized by?

Answer 13

Plants like bulrushes and water lilies, and small fish and insects

Question 14

What is found in the middle zone of a lake?

Answer 14

Open water with light penetration, phytoplankton, and fish

Question 15

What characterizes the lowest zone of a lake?

Answer 15

Deep water with no light penetration where plants do not grow

Question 16

What is the intertidal zone?

Answer 16

The shoreline area where animals and plants withstand waves and live out of water during low tide

Question 17

What is an estuary?

Answer 17

A rich ecosystem where fresh water from rivers mixes with salt water from the ocean

Question 18

What is the continental shelf?

Answer 18

A shelf of land extending from the edge of a continent below the ocean’s surface

Question 19

What factors lead to the development of adaptations in aquatic organisms?

Answer 19

• Temperature
• Light
• Pressure
• Salinity

Question 20

What is an adaptation?

Answer 20

A physical characteristic or behavior that increases a species’ chances of survival

Question 21

How do fish adapt to breathe in water?

Answer 21

They have gills to remove oxygen from water

Question 22

What is the significance of temperature for fish survival?

Answer 22

Fish can only survive in specific temperature ranges; some have natural antifreeze for cold waters

Question 23

How do plants in lakes adapt to seasonal changes?

Answer 23

They grow during summer and die back in winter

Question 24

What happens to fish if a factory discharges hot water into a lake?

Answer 24

The temperature change could harm the fish

Question 25

What adaptations do organisms in moving water have?

Answer 25

They may attach to rocks or dig into sand for protection

Question 26

What is a population in ecological terms?

Answer 26

A group of organisms of the same species living in a particular area

Question 27

How does the diversity of living things in salt water compare to fresh water?

Answer 27

Greater in salt water due to more varied environments

Question 28

What is the relationship between water quality and living things?

Answer 28

Water quality directly affects the health and diversity of aquatic organisms

Question 29

Fill in the blank: The most diverse ecosystems are the ______.

Answer 29

Tropical rain forests

Question 30

Fill in the blank: An ______ is an area where fresh water from rivers meets salt water from the ocean.

Answer 30

Estuary

Question 31

What is a population in ecological terms?

Answer 31

A group of organisms of the same species that live in a particular area.

Question 32

How can populations of organisms change?

Answer 32

Changes can be an increase or decrease in the number of individuals, or a change in the ratio of females to males, or young to old.

Question 33

What are the three major types of changes to populations?

Answer 33

* Seasonal changes * Short-term changes * Long-term changes

Question 34

What is an example of seasonal changes in populations?

Answer 34

Populations of freshwater organisms swell during warm summer months and decrease during winter.

Question 35

What is a short-term change in populations?

Answer 35

Changes that take place over a short period and do not happen every year, often due to natural events or human activities.

Question 36

What is an example of a long-term change in a population caused by human activities?

Answer 36

The introduction of zebra mussels to the Great Lakes.

Question 37

What are zebra mussels and why are they significant?

Answer 37

Zebra mussels are a European species introduced to the Great Lakes that compete with native shellfish populations.

Question 38

True or False: Overfishing is the only reason for the decline in cod populations.

Answer 38

False

Question 39

What factors are affecting the wild salmon population off British Columbia?

Answer 39

* Overfishing * Loss of streams for egg-laying * Warming of the ocean

Question 40

What is the main reason for the decrease in the cod population off Newfoundland?

Answer 40

Overfishing, along with other factors.

Question 41

Fill in the blank: A population change may indicate that something in the _______ has changed.

Answer 41

[ecosystem]

Question 42

What is an example of a natural event that causes short-term changes in fish populations?

Answer 42

The effect of El Niño on fish populations off the coast of South America.

Question 43

How does changing water quality affect aquatic organisms?

Answer 43

Different species have varying water quality requirements, and even slight changes can affect specialized organisms.

Question 44

What happens to a lake with high alkalinity?

Answer 44

It may not support many different types of organisms.

Question 45

What is an algal bloom?

Answer 45

A rapid and large increase in the growth of algae in a body of water, often caused by excess fertilizers.

Question 46

What can happen when algal blooms occur?

Answer 46

They block light to underwater plants, leading to their death and a subsequent decrease in oxygen for other organisms.

Question 47

What effect does acid rain have on lakes?

Answer 47

It can change the lake’s water to a level too acidic to support most life.

Question 48

What is the average number of mussels found in a 1-m2 square if the counts are 22, 26, 20, 18, and 16?

Answer 48

The average is 20.4 mussels.

Question 49

How do human activities affect aquatic ecosystems?

Answer 49

They can lead to pollution, overfishing, and habitat destruction, which impact populations and biodiversity.

Question 50

What is the significance of the Grand Banks for cod fishing?

Answer 50

It was once a rich fishing area but has seen a dramatic decrease in cod population due to overfishing.

Question 51

What role do brine shrimp play in aquaculture?

Answer 51

They are used as fish food for aquariums and in commercial aquaculture.

Question 52

What occurs when too much fertilizer enters the water from farmers' fields?

Answer 52

Abundant algal growth covers the surface, blocking light to underwater plants ## Footnote This phenomenon is often referred to as an algal bloom.

Question 53

What happens to underwater plants when algal blooms block light?

Answer 53

They can no longer photosynthesize, leading to their death ## Footnote Photosynthesis is essential for plant survival as it allows them to produce oxygen.

Question 54

What is the consequence of underwater plants dying due to lack of light?

Answer 54

Other organisms soon die because there are no plants producing oxygen ## Footnote The decline in oxygen levels can lead to a dead zone in aquatic ecosystems.

Question 55

True or False: Algal blooms can lead to an increase in oxygen levels in aquatic ecosystems.

Answer 55

False ## Footnote Algal blooms block sunlight and reduce oxygen levels as underwater plants die.

Question 56

What is an example of human impact on aquatic ecosystems?

Answer 56

Fertilizer runoff leading to algal blooms ## Footnote This runoff introduces excess nutrients into the water, promoting algal growth.

Question 57

Fill in the blank: Algal bloom forms when the amount of _______ in the water increases greatly.

Answer 57

dissolved nutrients ## Footnote These nutrients often come from fertilizers used in agriculture.

Question 58

What environmental issue is shown in Figure 3.17?

Answer 58

Acid rain affecting a lake ## Footnote Acid rain can significantly harm aquatic ecosystems and water quality.