Biology AHSGE: Standard XVBiomes of the World

Biomes and Native Organisms

CONTENT STANDARD 15. Identify biomes based on environmental factors and native organisms.

ELIGIBLE CONTENTA. Identify terrestrial biomes including the tundra,

desert, rainforest, grassland, taiga (coniferous forest), and the temperate deciduous forest.

B. Identify the aquatic biomes including freshwater and marine.

C. Identify terrestrial and aquatic biomes based on the rainfall and temperature characteristics.

What is a biome?Largest geographic biotic unit, a major community of plants and animals with similar life forms and environmental conditions.

How are biomes formed?•Distributed across the Earth based primarily on climate. •Similar climate = similar biomes

•Latitude affects climate•The farther north or south of the equator, the colder the temperature

•Elevation affects climate• The higher, the colder.

•Elevation and latitude often similar

How many terrestrial biomes are there?

Terrestrial Biomes

• Tropical Rainforest• Tropical Savanna• Desert• Chaparral• Grassland• Temperate Deciduous Forest• Temperate Boreal Forest• Tundra

Some disagreement among scientists,most agree on these:

Native Species

• Indigenous- Naturally from an area– Characteristic of an ecosystem– Keystone species- Organism that is vital to an ecosystem

• Without it, ecosystem would fail• Examples:

– Beavers- create ponds, streams or swamps– Otters- control sea urchin populations in kelp beds– Grizzly bears- provide nourishment to forest floor with salmon

carcasses– Elephants- transform landscape to make more accessible– Prairie dogs and gopher tortoises- Dig burrows and tunnels other

animals use

Tropical Rainforest• Near the equator• More than 200 cm of rain annually• Temperatures typically fall between 20oC

and 25oC (68-77° F) for the entire year• 50% of all the world’s animal species may

be found here• Multiple canopy layers• Large amounts of transpiration• Highest biodiversity: birds, bats, small

mammals, insects, monkeys, and jaguars; orchids, bromeliads, vines, ferns, mosses and palms

Tropical Savanna

• Grasslands/few scattered trees• Wet and dry season• Hot temperatures• Annual rainfall is between 50 and

127 cm• More species of grazing mammals

than any other biome• Animals migrate • Lions, zebras, giraffes, hyenas, etc.

Desert• Between 25o and 40o latitude• Less than 25 cm of rain annually• Temperatures range between 20oC and

25oC (68-77°F) but some extreme deserts can reach temperatures higher than 38oC (100°F) and lower than –15oC (5°F)

• Animals burrow and remove water from food: Kangaroo rats (rodents), rabbits, skunks, and burrowing owls, reptiles, and birds; all mostly active at night

• Succulents and plants with very reduced leaf surfaces

Chaparral

• Between 32o and 40o latitude on the west coast of continents

• Between 35 and 70 cm of rain, usually in the winter

• Extremely resistant to drought and weather events

Temperate Grassland• Dry climate/trees are found only near

water sources such as streams• Between 50 and 90 cm of rainfall each

year• Summer temperatures can reach up to

38oC (100°F), and winter temperatures can fall to –40oC (-40°F)

• Prairie dogs; ground owls• Broad-leaf trees and many wildflowers• Nutrient-rich soil with thick topsoil layer

Temperate Deciduous Forest

• Moderate climate• Most trees will lose their leaves in the

winter• Temperatures range between –30oC

and 30oC (-22° F to 104° F)• 75 to 150 cm of precipitation• Well developed understory• High biodiversity: deer, squirrels, mice,

raccoons, salamanders, snakes, frogs, and insects

Temperate Boreal Forest• Also known as Taiga (coniferous forest)• Between 45o and 60o North latitude• Cold climate with summer rains• Patchy permafrost- permanently frozen soil starting as high as a few

centimeters below the surface – which severely limits plant growth• Many lakes, ponds, rivers and bogs• Very few reptiles• Limited understory• Snow is primary form of precipitation (40 – 100 cm annually)• Mosses and evergreen trees; drought resistant• Summer birds and insects, bears, moose, etc.

Temperate Boreal Forest

Tundra• Means treeless or marshy plain

– Prairie potholes

• Characterized by permafrost Winter temperatures average –34oC (93°F) while summer temperatures usually average below 10oC (50°F)

• Lowest precipitation (15–25 cm per year) but ground is usually wet/snow because of low evaporation

• Coastal species: polar bears, seals, penguins• Inland: Caribou, ducks and geese• Low-growing plants with shallow roots; reproduce by

budding

Tundra

Antarctic Desert

• Low precipitation• No permafrost• Low species diversity • Moss and algae

vegetation• Lichens • Some invertebrates

Aquatic Biomes- Water

• Most stable average daily temperature

• Freshwater- Low to no salinity– Glacial lakes– Rivers– Lakes/ponds

• Estuary- brackish– Varying salinity levels

• Marine- ocean– High salinity level

Estuarian Biome

Marine Biome

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