Ecosystems and Biomes
The Desert
Characteristics
A biome that receives very little rain Nearly on every continent Earth’s driest ecosystem Most are hot during the day and cold at night Antarctica is an exception where it is cold all of the time.
Biodiversity
Animals: Lizards, bats, wood peckers, snakes Plants: Spiny cactus and thorny shrubs Human Impact
Cities, farms, and recreational areas use valuable water Plants grow slowly, so when damaged, recovering takes many years.
The Grassland
Characteristics
Biome where grasses are the dominant plants Also known as: prairies, savannas, and meadows Produce wheat, corn, oats, rye, and barley Have a wet and dry season Deep, fertile soil supports plant growth Sod – helps soil absorb and hold water during periods of drought.
Biodiversity
Animals: Large herbivores like bison and elk, insects, birds, rabbits, prairie dogs, and snakes Predators: Hawks, ferrets, coyotes, wolves Africa: Giraffes, zebras, lions Australia – Kangaroos, wallabies, wild dogs Plants: Trees along streams and rivers and wild flowers during wet season
Human Impact
People plow to raise crops Hunting and loss of habitat cause large herbivores to become less common.
Tropical Rain forest
Characteristics
Grow near the equator Receive large amounts of rain Dense growth of tall leafy trees Weather is warm and wet year round Soil is shallow easily washed away by rain Less than 1% of sunlight reaches the forest floor. ½ the Earth’s species live here Most live in the canopy (uppermost part of the forest)
Biodiversity
Animals: Insects make up the largest group of tropical animals. Insects: beetles, termites, ants, bees, and butterflies Larger animals include: parrots, toucans, snakes, frogs, flying squirrels, fruit bats, monkeys, jaguars, and ocelots. Plants: Few plants live on the dark forest floor Vines climb the trunks of all trees Mosses, ferns, and orchids live on branches in the canopy
Human Impact
People have cleared more than half of Earth’s tropical rain forests for lumber, farms, and ranches Some organizations encourage people to use less wood
Temperate Rain FOrest
Characteristics
Relatively mild climates with distinct seasons Moist ecosystems mostly in coastal areas Not as warm as tropical rain forests Winters are mild and rainy Summers are cool and foggy Soil is rich and moist
Biodiversity
Animals: mosquitoes, butterflies, frogs, salamanders, woodpeckers, owls, eagles, chipmunks, raccoons, deer, elk, bears, foxes, cougars. Plants: dominated by spruce, hemlock, cedar, fir, and redwood trees (grow large and tall) Also has fungi, ferns, mosses, vines, and small flowering plants
Human Impact
Trees are a source of lumber Rich soil enables cut forests to grow back
Temperate Deciduous Forest
Characteristics
Most common forest ecosystems in the United States Mostly deciduous trees, which lose their leaves in the fall. Winter temperatures are often below freezing. Snow is common. Summers are hot and humid. Soil is rich in nutrients and supports a large amount of diverse plant growth.
Biodiversity
Animals: snakes, ants, butterflies, birds, raccoons, opossums, and foxes common Some animals, including chipmunks and bats, spend the winter in hibernation Many birds and some butterflies migrate to warmer climates for the winter. Plants: Maples, oaks, birches, and other deciduous trees stop growing during the winter and grow again in the spring.
Human Impact
Humans have cleared thousands of acres for farms and cities.
Taiga
Characteristics
A forest biome consisting mostly of cone-bearing evergreen trees Exists only in the northern hemisphere Occupies more space on Earth’s continents than any other biome Winters are long, cold, and snowy Summers are short, warm, and moist. Soil is thin and acidic
Biodiversity
Animals: Owls, mice, moose, bears, other cold-adapted species Plants: Evergreen trees such as spruce, pine, and fir are thin and shed snow easily.
Human Impact
Tree harvesting reduces taiga habitat
Tundra
Characteristics
Cold, dry, and treeless Most is south of the North Pole, but exists in mountainous areas at high altitudes. Winters are long, dark, and freezing Summers are short and cool The growing season is only 50-60 days Permafrost – a layer of permanently frozen soil – prevents deep root growth
Biodiversity
Animals: Hibernate or migrate south during winter. Few animals including lemmings live in tundras year round. Plants: Shallow-rooted mosses, lichens, and grasses Human Impact
Drilling for oil and gas can interrupt migration patterns
Characteristics
A biome that receives very little rain Nearly on every continent Earth’s driest ecosystem Most are hot during the day and cold at night Antarctica is an exception where it is cold all of the time.
Biodiversity
Animals: Lizards, bats, wood peckers, snakes Plants: Spiny cactus and thorny shrubs Human Impact
Cities, farms, and recreational areas use valuable water Plants grow slowly, so when damaged, recovering takes many years.
The Grassland
Characteristics
Biome where grasses are the dominant plants Also known as: prairies, savannas, and meadows Produce wheat, corn, oats, rye, and barley Have a wet and dry season Deep, fertile soil supports plant growth Sod – helps soil absorb and hold water during periods of drought.
Biodiversity
Animals: Large herbivores like bison and elk, insects, birds, rabbits, prairie dogs, and snakes Predators: Hawks, ferrets, coyotes, wolves Africa: Giraffes, zebras, lions Australia – Kangaroos, wallabies, wild dogs Plants: Trees along streams and rivers and wild flowers during wet season
Human Impact
People plow to raise crops Hunting and loss of habitat cause large herbivores to become less common.
Tropical Rain forest
Characteristics
Grow near the equator Receive large amounts of rain Dense growth of tall leafy trees Weather is warm and wet year round Soil is shallow easily washed away by rain Less than 1% of sunlight reaches the forest floor. ½ the Earth’s species live here Most live in the canopy (uppermost part of the forest)
Biodiversity
Animals: Insects make up the largest group of tropical animals. Insects: beetles, termites, ants, bees, and butterflies Larger animals include: parrots, toucans, snakes, frogs, flying squirrels, fruit bats, monkeys, jaguars, and ocelots. Plants: Few plants live on the dark forest floor Vines climb the trunks of all trees Mosses, ferns, and orchids live on branches in the canopy
Human Impact
People have cleared more than half of Earth’s tropical rain forests for lumber, farms, and ranches Some organizations encourage people to use less wood
Temperate Rain FOrest
Characteristics
Relatively mild climates with distinct seasons Moist ecosystems mostly in coastal areas Not as warm as tropical rain forests Winters are mild and rainy Summers are cool and foggy Soil is rich and moist
Biodiversity
Animals: mosquitoes, butterflies, frogs, salamanders, woodpeckers, owls, eagles, chipmunks, raccoons, deer, elk, bears, foxes, cougars. Plants: dominated by spruce, hemlock, cedar, fir, and redwood trees (grow large and tall) Also has fungi, ferns, mosses, vines, and small flowering plants
Human Impact
Trees are a source of lumber Rich soil enables cut forests to grow back
Temperate Deciduous Forest
Characteristics
Most common forest ecosystems in the United States Mostly deciduous trees, which lose their leaves in the fall. Winter temperatures are often below freezing. Snow is common. Summers are hot and humid. Soil is rich in nutrients and supports a large amount of diverse plant growth.
Biodiversity
Animals: snakes, ants, butterflies, birds, raccoons, opossums, and foxes common Some animals, including chipmunks and bats, spend the winter in hibernation Many birds and some butterflies migrate to warmer climates for the winter. Plants: Maples, oaks, birches, and other deciduous trees stop growing during the winter and grow again in the spring.
Human Impact
Humans have cleared thousands of acres for farms and cities.
Taiga
Characteristics
A forest biome consisting mostly of cone-bearing evergreen trees Exists only in the northern hemisphere Occupies more space on Earth’s continents than any other biome Winters are long, cold, and snowy Summers are short, warm, and moist. Soil is thin and acidic
Biodiversity
Animals: Owls, mice, moose, bears, other cold-adapted species Plants: Evergreen trees such as spruce, pine, and fir are thin and shed snow easily.
Human Impact
Tree harvesting reduces taiga habitat
Tundra
Characteristics
Cold, dry, and treeless Most is south of the North Pole, but exists in mountainous areas at high altitudes. Winters are long, dark, and freezing Summers are short and cool The growing season is only 50-60 days Permafrost – a layer of permanently frozen soil – prevents deep root growth
Biodiversity
Animals: Hibernate or migrate south during winter. Few animals including lemmings live in tundras year round. Plants: Shallow-rooted mosses, lichens, and grasses Human Impact
Drilling for oil and gas can interrupt migration patterns
Aquatic Ecosystems
Four major types
Freshwater Wetland Estuary Ocean
Abiotic Factors
Temperature Sunlight Dissolved oxygen gas Salinity – the amount of salt dissolved in water
Adaptations
Gills of fish separate oxygen from water
Plants have small pores in leaves and roots FreshWater: Streams and Rivers
Characteristics
Streams form from underground sources of water, such as springs or from runoff from rain and melting snow. Stream water is often clear. Soil particles are quickly washed downstream. Oxygen levels in streams are high because air mixes into the water as it splashes over rocks. Rivers form when streams flow together. Soil that washes into a river from streams or nearby land can make river water muddy. Soil also introduces nutrients, such as nitrogen, into rivers. Slow-moving river water has higher levels of nutrients and lower levels of dissolved oxygen.
Biodiversity
Willows, cottonwoods, and other water-loving plants grow along streams and on riverbanks. Species adapted to fast-moving water include: trout, salmon, crayfish, and many insects. Species adapted to slow-moving water include snails and catfish.
Human Impact
People take water from streams and rivers for drinking, laundry, bathing, crop irrigation, and industrial purposes. Hydroelectric plants use the energy in flowing water to generate electricity. Dams stop the water’s flow. Runoff from cities, industries, and farms is a source of pollution.
Freshwater: Ponds and Lakes
Characteristics
Not flowing downhill and in low areas of land. Ponds are shallow and warm. Sunlight reaches the bottom of most ponds. Pond water is often high in nutrients. Lakes are larger and deeper than ponds. Sunlight penetrates into the top few feet of lake water. Deeper water is dark and cold.
Biodiversity
Plants surround ponds and lake shores. Surface water in ponds and lakes contains plants, algae, and microscopic organisms that use sunlight for photosynthesis. Organisms living in shallow water near shorelines include cattails, reeds, insects, crayfish, frogs, fish and turtles. Fewer organisms live in the deeper, colder water of lakes where there is little sunlight. Lake fish include: perch, trout, bass, and walleye. Human Impact
Humans fill in ponds and lakes with sediment to create land for houses and other structures. Runoff from farms, gardens, and roads washes pollutants into ponds and lakes, disrupting food webs.
Wetlands
Characteristics
Have a thin layer of water covering soil that is wet most of the time. Contain freshwater, salt water, or both Most fertile ecosystem Form at the edges of lakes and ponds in low areas on land Saltwater wetlands form along ocean coasts Nutrient levels and biodiversity are high Trap sediments and purify water Plants and microscopic organisms filter out pollution and waste materials.
Biodiversity
Water-tolerant plants include grasses and cattails. Few trees live in saltwater wetlands Trees in freshwater wetlands include cottonwoods, willows, and swamp oaks. Insects are abundant and include flies, mosquitoes, dragonflies, and butterflies. More than one-third of North American bird species, including ducks, geese, herons, loons, warblers, and egrets, use wetlands for nesting and feeding. Other animals include: alligators, turtles, frogs, snakes, salamanders, muskrats, and beavers.
Human Impact
Used to be considered unimportant environments. Water was drained away to build homes and roads and to raise crops. Many wetlands are now being preserved Wetlands that were drained are being restored
Estuaries
Characteristics
Along coastlines where streams or rivers flow into a body of salt water. Where freshwater in rivers meet salt water in oceans Salinity depends on rainfall, the amount of freshwater flowing from land, and the amount of salt water pushed in by tides. Help protect coastal land from flooding and erosion. Purify water and filter out pollution. Nutrient levels and biodiversity are high.
Biodiversity
Plants include: mangroves, pickleweeds, and seagrasses Animals include: worms, snails, and many species that people use for food, including oysters, shrimp, crabs, and clams Striped bass, salmon, flounder, and many other fish lay their egg here. Many species of birds use area for breeding, nesting, and feeding.
Human Impact
Many have been filled with soil to make land for roads and buildings. Destruction has reduced habitat for species and exposes the coastline to flooding and storm damage.
Open Ocean
Characteristics
High salinity From steep edges of continental shelves to the deepest parts of the ocean Amount of light depends on depth Photosynthesis can take place only in the uppermost, or sunlit, zone. Very little sunlight reaches the twilight zone. No light reaches the deepest water known as the dark zone. Decaying matter and nutrients float down from the sunlit zone, through the twilight and dark zones, to the sea floor.
Biodiversity
Sunlit Zone: Microscopic algae and other producers, jellyfish, tuna, mackerel, and dolphins Twilight Zone: Many species of fish stay here during the day and move to the sunlit zone at night to feed. Sea cucumbers, brittle stars, and other bottom-dwelling organisms feed on decaying matter that drifts down from above. Dark Zone: Organisms live near cracks in the seafloor where lava erupts and new seafloor forms.
Human Impact
Overfishing threatens many ocean fish. Trash discarded from ocean vessels or washed into oceans from land is a source of pollution. Animals such as seals become tangled in plastic or mistake it for food.
Coastal Ocean
Characteristics
Includes several types of ecosystems Continental Shelf – relatively shallow seabed surrounding a continent Intertidal Zone – ocean shore between the lowest low tide and the highest tide Sunlight reaches the bottom of shallow coastal ecosystems. Nutrients washed in from rivers and streams contribute to high biodiversity.
Biodiversity
Animals: mussels, fish, crabs, sea stars, dolphins, and whales Intertidal species have adaptations for surviving exposure to air during low tides and to heavy waves during high tides.
Human Impact
Oil spills and other pollution harm coastal organisms.
Coral Reef
Characteristics
Underwater structure made from outside skeletons of tiny, soft-bodied animals called coral. Most form in shallow tropical oceans. Protect coastlines from storm damage and erosion. High biodiversity
Biodiversity
Provide food and shelter for many animals including: parrotfish, groupers, angelfish, eels, shrimp, crabs, scallops, clams, worms, and snails.
Human Impact
Pollution, overfishing, and harvesting of coral threaten coral reefs.
Freshwater Wetland Estuary Ocean
Abiotic Factors
Temperature Sunlight Dissolved oxygen gas Salinity – the amount of salt dissolved in water
Adaptations
Gills of fish separate oxygen from water
Plants have small pores in leaves and roots FreshWater: Streams and Rivers
Characteristics
Streams form from underground sources of water, such as springs or from runoff from rain and melting snow. Stream water is often clear. Soil particles are quickly washed downstream. Oxygen levels in streams are high because air mixes into the water as it splashes over rocks. Rivers form when streams flow together. Soil that washes into a river from streams or nearby land can make river water muddy. Soil also introduces nutrients, such as nitrogen, into rivers. Slow-moving river water has higher levels of nutrients and lower levels of dissolved oxygen.
Biodiversity
Willows, cottonwoods, and other water-loving plants grow along streams and on riverbanks. Species adapted to fast-moving water include: trout, salmon, crayfish, and many insects. Species adapted to slow-moving water include snails and catfish.
Human Impact
People take water from streams and rivers for drinking, laundry, bathing, crop irrigation, and industrial purposes. Hydroelectric plants use the energy in flowing water to generate electricity. Dams stop the water’s flow. Runoff from cities, industries, and farms is a source of pollution.
Freshwater: Ponds and Lakes
Characteristics
Not flowing downhill and in low areas of land. Ponds are shallow and warm. Sunlight reaches the bottom of most ponds. Pond water is often high in nutrients. Lakes are larger and deeper than ponds. Sunlight penetrates into the top few feet of lake water. Deeper water is dark and cold.
Biodiversity
Plants surround ponds and lake shores. Surface water in ponds and lakes contains plants, algae, and microscopic organisms that use sunlight for photosynthesis. Organisms living in shallow water near shorelines include cattails, reeds, insects, crayfish, frogs, fish and turtles. Fewer organisms live in the deeper, colder water of lakes where there is little sunlight. Lake fish include: perch, trout, bass, and walleye. Human Impact
Humans fill in ponds and lakes with sediment to create land for houses and other structures. Runoff from farms, gardens, and roads washes pollutants into ponds and lakes, disrupting food webs.
Wetlands
Characteristics
Have a thin layer of water covering soil that is wet most of the time. Contain freshwater, salt water, or both Most fertile ecosystem Form at the edges of lakes and ponds in low areas on land Saltwater wetlands form along ocean coasts Nutrient levels and biodiversity are high Trap sediments and purify water Plants and microscopic organisms filter out pollution and waste materials.
Biodiversity
Water-tolerant plants include grasses and cattails. Few trees live in saltwater wetlands Trees in freshwater wetlands include cottonwoods, willows, and swamp oaks. Insects are abundant and include flies, mosquitoes, dragonflies, and butterflies. More than one-third of North American bird species, including ducks, geese, herons, loons, warblers, and egrets, use wetlands for nesting and feeding. Other animals include: alligators, turtles, frogs, snakes, salamanders, muskrats, and beavers.
Human Impact
Used to be considered unimportant environments. Water was drained away to build homes and roads and to raise crops. Many wetlands are now being preserved Wetlands that were drained are being restored
Estuaries
Characteristics
Along coastlines where streams or rivers flow into a body of salt water. Where freshwater in rivers meet salt water in oceans Salinity depends on rainfall, the amount of freshwater flowing from land, and the amount of salt water pushed in by tides. Help protect coastal land from flooding and erosion. Purify water and filter out pollution. Nutrient levels and biodiversity are high.
Biodiversity
Plants include: mangroves, pickleweeds, and seagrasses Animals include: worms, snails, and many species that people use for food, including oysters, shrimp, crabs, and clams Striped bass, salmon, flounder, and many other fish lay their egg here. Many species of birds use area for breeding, nesting, and feeding.
Human Impact
Many have been filled with soil to make land for roads and buildings. Destruction has reduced habitat for species and exposes the coastline to flooding and storm damage.
Open Ocean
Characteristics
High salinity From steep edges of continental shelves to the deepest parts of the ocean Amount of light depends on depth Photosynthesis can take place only in the uppermost, or sunlit, zone. Very little sunlight reaches the twilight zone. No light reaches the deepest water known as the dark zone. Decaying matter and nutrients float down from the sunlit zone, through the twilight and dark zones, to the sea floor.
Biodiversity
Sunlit Zone: Microscopic algae and other producers, jellyfish, tuna, mackerel, and dolphins Twilight Zone: Many species of fish stay here during the day and move to the sunlit zone at night to feed. Sea cucumbers, brittle stars, and other bottom-dwelling organisms feed on decaying matter that drifts down from above. Dark Zone: Organisms live near cracks in the seafloor where lava erupts and new seafloor forms.
Human Impact
Overfishing threatens many ocean fish. Trash discarded from ocean vessels or washed into oceans from land is a source of pollution. Animals such as seals become tangled in plastic or mistake it for food.
Coastal Ocean
Characteristics
Includes several types of ecosystems Continental Shelf – relatively shallow seabed surrounding a continent Intertidal Zone – ocean shore between the lowest low tide and the highest tide Sunlight reaches the bottom of shallow coastal ecosystems. Nutrients washed in from rivers and streams contribute to high biodiversity.
Biodiversity
Animals: mussels, fish, crabs, sea stars, dolphins, and whales Intertidal species have adaptations for surviving exposure to air during low tides and to heavy waves during high tides.
Human Impact
Oil spills and other pollution harm coastal organisms.
Coral Reef
Characteristics
Underwater structure made from outside skeletons of tiny, soft-bodied animals called coral. Most form in shallow tropical oceans. Protect coastlines from storm damage and erosion. High biodiversity
Biodiversity
Provide food and shelter for many animals including: parrotfish, groupers, angelfish, eels, shrimp, crabs, scallops, clams, worms, and snails.
Human Impact
Pollution, overfishing, and harvesting of coral threaten coral reefs.
