Biome

Chapter 36 Biomes

What is a Biome? Biome—a large region of the earth that has characteristic kinds of organisms. Identified by their dominant plant life and distinctive groups of animals. Biomes are determined by climate— average yearly rainfall and temperature.

Land Biomes and their Climates Biome Tundra Coniferous forest Deciduous forest Rainforest Grasslands Deserts

Ave. Yearly Rainfall less than 25 cm

Ave. Yearly Temp. -25oC to 4oC .

35-75 cm

-10oC to 14oC

.

75-125 cm 200-450 cm 25-75 cm less than 25 cm

6oC to 28oC 25oC to 28oC 0oC to 25oC 24oc to 40oC

. . . .

Biome Map

Grassland

The Tundra Tundra—treeless biome near the North Pole. Characteristics Cold temperatures Little rainfall Long, cold winters with little or no daylight Short, cool summers with 24 hours of daylight One meter of soil thaws in summer. The rest stays frozen--permafrost

Plants of the Tundra Extreme cold, a short growing season, and shallow soil allow very few plants to grow in the tundra. Most common are grasses, mosses, and lichens. No trees!!!

Animals of the Tundra Most common: caribou, reindeer, and musk oxen. Small mammals include the Arctic fox, Arctic hare, wolves, and snow shoe rabbits. Ducks and geese nest there in the summer. Lots of black flies and mosquitoes

Coniferous Forest Coniferous Forest — broad region south of the tundra made up of conebearing trees (Conifers) Characteristics: Long, cold winters Short summers

Plants of the Coniferous Forest Conifers have needleshaped leaves with a waxy coat to protect them from freezing and water loss. Examples: spruce, fir, and pine trees.

Animals of the Coniferous Forest Many large and small animals including: moose, black bear, deer, squirrels, lynx, chipmunks, eagles and migratory birds.

Coniferous Forests of N. America Ecologists recognize three areas of coniferous forests in North America: Taiga—northern Canada and Alaska Spruce-moose belt —south of the taiga, covering most of Canada and Northern U.S. Southern Pine Forest —covers most of southeastern U.S.

Deciduous Forest Deciduous Forest —located south of taiga, it is the dominant biome of the eastern U.S. and Europe. Characteristics: Cold winters Warm summers Trees that lose their leaves

Plants of the Deciduous Forest Many kinds of broadleafed trees that lose their leaves seasonally (deciduous). Loosing leaves prevents water loss during winter. Examples: maples, oaks, chestnuts and elms.

Animals of the Deciduous Forest A deciduous forest supports a large number of different kinds of animals. Examples: deer, foxes, raccoons, skunks, rabbits, bears, reptiles, amphibians, many insects and birds. Many of these will migrate to warmer climates during the winter.

Tropical Rainforest Tropical Rainforest —located near the equator. Support more than ½ of all plant and animal species on Earth. Characteristics: Warm all year with at least 200 cm of rain/year Trees do not lose their leaves, creating a dense canopy that supports much of the animal life

Plants of the Rainforest Rainforest plants require several adaptations to survive in the hot, humid and wet conditions of the rainforest: Thin, smooth bark limits growth of other plants on the trees. Climbing vines can be rooted in the ground and draped over tall trees to reach sunlight.

Leaves with drip tips to allow excess water to fall off; preventing fungus growth. Buttresses and stilt roots give tall trees stability in shallow, wet soil. Epiphytes (plants that grow on trees to get more sunlight) Bromeliads (flowers that trap water)

thin bark

bromeliad

Climbing vines

stilt roots buttress drip leaves

epiphyte

Animals of the Rainforest Rainforests are home to 50% of the world’s animals. The different rainforests of the world support different populations of animals. Since the climate is the same year round, the animals that live there cannot tolerate changes in temperature, light, or rain.

Grasslands Grasslands--do not receive enough rainfall (25-75cm/ yr.) to support trees. Characteristics: Hot, dry summers Cold, snowy winters Fertile soil ideal for farming Dominant biome of central U.S. (bread-basket)

Plants of the Grasslands Many crops are grown in the grasslands including: Wheat Oats Barley Corn

Animals of the Grassland Many grazing animals live in the grasslands including: bison, antelope, cattle, and sheep. Also, coyotes, jackrabbits and rattlesnakes are common.

Deserts Desert—rainfall is less than 25 cm/ yr. Characteristics: Defining characteristic of all deserts is that they are dry. The temperature of a desert is determined by its geographic location. Many are hot during the day and cool at night (Sahara in Africa). Others are actually cold all the time (Gobi in Mongolia). All deserts have great temperature changes from day to night (days are much warmer than nights).

Plants of the Desert Some deserts have no plants. Others have sparse plants life including:

Tumble weed (Russian thistle)

Joshua tree (largest of the yucca)

Cactus and yucca

Desert flowers

Animals of the Desert Most are small and have evolved adaptations to solve the heat and water problems, such as: nocturnal activity, estivation, dissipating heat, retaining water and getting water from plants. Examples:

Road runner

Jack rabbits Kangaroo rat

Prairie dogs

Desert iguana

Water Biomes Water covers 75% of the earth’s surface. Two main types of water biomes:

Marine biomes

Freshwater biomes

Marine Biomes Marine biome —saltwater biome. It is the largest biome on earth. Three areas of the marine biome: Ocean Intertidal zone Estuary

Ocean Ocean —part of the marine biome that is constantly underwater. Upper level receives the most light and is home to the most organisms including plankton (microscopic organisms) and many fish, squid and turtles.

Intertidal Zone Intertidal zone —part of the marine biome that is underwater at high tide and exposed at low tide. Organisms here are adapted to being exposed to the air during part of the day. They also must protect themselves from being hit by waves. They include: clams, oysters, mussels and crabs

Estuary Estuary —part of the marine biome where a freshwater river flows into the ocean. They are rich in nutrients and support many kinds of organisms.

Saltwater/freshwater line visible

Freshwater Biomes Two types of freshwater biomes exist: Still-water biomes consisting of lakes and ponds. Running-water biomes consisting of streams and rivers.

Still-water Biomes Lakes and ponds make-up the still-water biomes. Algae and plankton are abundant and support the other animal life.

Running-water Biomes The amount of dissolved oxygen in the water determines what kinds of organisms are found in rivers and streams. Fast-moving streams or rivers are usually cool and therefore have a lot of dissolved oxygen. Little plankton is available so dead leaves and insect larva are important sources of food. Fish such as trout are common.

Running Water Biomes In slow-moving streams or rivers, plankton is the base of the food-chain. Catfish and bass are common.