biomes

terrestrial biomes

Terrestrial biomes are land-based biomes. They range from arctic tundra to tropical rainforests. Figure 23.18 shows the locations of the worlds major terrestrial biomes.

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aquatic biomes and sunlight

Only the top 200 meters or so of water receive enough sunlight for photosynthesis. This part of the water is called the photic zone. Below 200 meters, there is too little sunlight for photosynthesis to take place. This part of the water is called the aphotic zone. In this zone, food must come from other sources. It may be made by chemosynthesis, in which microorganisms use energy in chemicals instead of sunlight to make food. Or, food may drift down from the water above.

aquatic biomes

Aquatic biomes are water-based biomes. They include both freshwater biomes, such as rivers and lakes, and marine biomes, which are salt-water biomes in the ocean. The primary producers in most aquatic biomes are phytoplankton. Phytoplankton consist of microscopic bacteria and tiny algae that make food by photosynthesis. Unlike terrestrial biomes, which are determined mainly by temperature and moisture, aquatic biomes are determined mainly by sunlight and dissolved substances in the water. These factors, in turn, depend mainly on depth of water and distance from shore.

examples of terrestrial biomes

You can read about three different terrestrial biomes in Figure 23.19: tropical rainforest, temperate grassland, and tundra. You can learn more about these and other terrestrial biomes by watching this video: MEDIA Click image to the left or use the URL below. URL:

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terrestrial biomes and climate

Plants are the primary producers in terrestrial biomes. They make food for themselves and other organisms by photosynthesis. The major plants in a given biome, in turn, help determine the types of animals and other organisms that can live there. Which plants grow in a given biome depends mainly on climate. Climate is the average weather in a place over a long period of time. The major climatic factors affecting plant growth are temperature and moisture.

ocean zones

Zones in the oceans include the intertidal, pelagic, and benthic zones. The types of organisms found in these ocean zones are also determined by such factors as depth of water and distance from shore, among other factors. One of the most familiar ocean zones is the intertidal zone. This is the narrow strip along a coastline that is covered by water at high tide and exposed to air at low tide. You can see an example of an intertidal zone in Figure 23.21. There are plenty of nutrients and sunlight in the intertidal zone. Producers here include phytoplankton and algae. Other organisms include barnacles, snails, crabs, and mussels. They must have adaptations for the constantly changing conditions in this zone. Other ocean zones are farther from shore in the open ocean. All the water in the open ocean is called the pelagic zone. It is further divided by depth: The top 200 meters of water is the photic zone. Producers here include seaweeds and phytoplankton. Other organisms are plentiful. They include zooplankton and animals such as fish, whales, and dolphins.

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freshwater zones

A lake is an example of a freshwater biome. Water in a lake generally forms three different zones based on water depth and distance from shore. The shallow water near the shore is called the littoral zone. It has diverse community of organisms. There is adequate light for photosynthesis and plenty of dissolved oxygen and nutrients. Producers include algae and aquatic plants (see Figure 23.20). Animals in this zone may include insects, crustaceans, fish, and turtles. The top layer of water farther from shore is called the limnetic zone. There is enough light for photosynthesis and plenty of dissolved oxygen. However, dissolved nutrients tend not to be as plentiful as they are in the littoral zone. Producers here are mainly phytoplankton. A variety of zooplankton and fish also occupy this zone. The deeper water of a lake makes up the profundal zone. There isnt enough light for photosynthesis in this zone, so most organisms here eat dead organisms that drift down from the water above. Organisms in the profundal zone may include clams, snails, and some species of fish.

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aquatic biomes and dissolved substances

In addition to sunlight, aquatic producers also need dissolved oxygen and nutrients. Water near the surface generally contains more dissolved oxygen than deeper water. Many nutrients enter the water from the land. Therefore, water nearer shore usually contains more dissolved nutrients than water farther from shore.

instructional diagrams

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questions

Which statement is always true of ecosystems in the same biome?

a. They have the same type of primary producers.

b. They are located on the same continent.

c. They have similar abiotic factors.

-->  d. two of the above

All ecosystems at the same latitude are placed in the same biome.

a. true

-->  b. false

Ecosystems in the same biome have the same type of primary producers.

-->  a. true

b. false

Which of the following is not a type of tropical biome?

-->  a. tundra

b. rainforest

c. dry forest

d. desert

A temperate grassland has

a. a wet climate.

b. many deciduous trees.

-->  c. excellent soil quality.

d. two of the above

Plants are the primary producers in all of Earths biomes.

a. true

-->  b. false

Which plants grow in a particular biome depends mainly on climate.

-->  a. true

b. false

The primary producers in most aquatic biomes are

a. plants.

b. zooplankton.

-->  c. phytoplankton.

d. none of the above

Arctic tundra is found only at low latitudes.

a. true

-->  b. false

The most important factors that determine the nature of aquatic biomes include

-->  a. sunlight.

b. latitude.

c. temperature.

d. precipitation.

Rivers and lakes are examples of marine biomes.

a. true

-->  b. false

Deep water generally contains more dissolved oxygen than water near the surface.

a. true

-->  b. false

__primary producers in most aquatic biomes

a. photic zone

b. biome

c. climate

d. littoral zone

-->  e. phytoplankton

f. marine

g. aphotic zone

__shallow water near the shore of a lake

a. photic zone

b. biome

c. climate

-->  d. littoral zone

e. phytoplankton

f. marine

g. aphotic zone

__part of a body of water that is too deep for sunlight to reach

a. photic zone

b. biome

c. climate

d. littoral zone

e. phytoplankton

f. marine

-->  g. aphotic zone

__general term for a group of similar ecosystems

a. photic zone

-->  b. biome

c. climate

d. littoral zone

e. phytoplankton

f. marine

g. aphotic zone

The littoral zone of a lake is the deep water near the bottom.

a. true

-->  b. false

In aquatic biomes, water closer to shore usually contains more dissolved nutrients than water farther

-->  a. true

b. false

__top 200 meters of a body of water

-->  a. photic zone

b. biome

c. climate

d. littoral zone

e. phytoplankton

f. marine

g. aphotic zone

All the water in the open ocean far from shore is called the pelagic zone.

-->  a. true

b. false

__average weather in a place over a long period of time

a. photic zone

b. biome

-->  c. climate

d. littoral zone

e. phytoplankton

f. marine

g. aphotic zone

__of or relating to the ocean

a. photic zone

b. biome

c. climate

d. littoral zone

e. phytoplankton

-->  f. marine

g. aphotic zone

There is not enough sunlight for photosynthesis in the aphotic zone of a body of water.

-->  a. true

b. false

The benthic zone of the ocean includes the sediments at the bottom of the water.

-->  a. true

b. false

Terrestrial biomes include all of the following except

a. tropical dry forests.

b. alpine tundra.

-->  c. polar forests.

d. boreal rainforests.

Which of the following is not a type of temperate biome?

a. deciduous forest

b. desert

c. rainforest

-->  d. savanna

A tropical rainforest has

a. very high biodiversity.

b. a humid climate.

c. a year-round growing season.

-->  d. all of the above

The main factors that determine aquatic biomes include

a. temperature.

b. types of plants.

-->  c. dissolved substances.

d. two of the above

The limnetic zone of a lake has

-->  a. enough light for photosynthesis.

b. more dissolved nutrients than any other lake zone.

c. less dissolved oxygen than any other lake zone.

d. none of the above

The types of plants found in tundra biomes include

a. mosses.

b. grasses.

c. trees.

-->  d. two of the above

Reptiles live in all of the following biomes except

-->  a. tundr

b. tropical rainforest.

c. tropical dry forest.

d. temperate grasslan

diagram questions

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