Presentation on theme: "“Land Biomes of the World” Mrs. Hartge’s Science Class."— Presentation transcript:
“Land Biomes of the World” Mrs. Hartge’s Science Class
The global ecosystem is called the biosphere –It is the sum of all the Earth's ecosystems –The biosphere is the most complex level in ecology The biosphere is the total of all of Earth's ecosystems THE BIOSPHERE Figure 34.2A
The biosphere is self-contained –except for energy obtained from the sun and heat lost to space Each habitat has a unique community of species Figure 34.2B
Abiotic Factors Abiotic factors are those non-living physical and chemical factors which affect the ability of organisms to survive and reproduce.
Abiotic Factors Abiotic factors vary in the environment and determining the types and numbers of organisms that exist in that environment. light intensity temperature range type of soil or rock pH level (acidity or alkalinity) water availability dissolved gases level of pollutant
The most important abiotic factors that determine the biosphere's structure and dynamics include –solar energy –water –temperature Physical and chemical factors influence life in the biosphere
Disturbances such as fires, hurricanes, and volcanic eruptions are also abiotic factors Figure 34.4
Biotic Factors Biotic factors are all the living things or their materials that directly or indirectly affect an organism in its environment. This would include organisms, their presence, parts, interaction, and wastes. Factors such as parasitism, disease, and predation (one animal eating another) would also be classified as biotic factors.
The presence and success of a species in a particular place depends upon its ability to adapt Natural selection adapts organisms to abiotic and biotic factors –Biotic factors include predation and competition Organisms are adapted to abiotic and biotic factors by natural selection Figure 34.5
Climate often determines the distribution of communities Earth's global climate patterns are largely determined by the input of solar energy and the planet's movement in space Regional climate influences the distribution of biological communities
Most climatic variations are due to the uneven heating of Earth's surface –This is a result of the variation in solar radiation at different latitudes Figure 34.6A Low angle of incoming sunlight Sunlight directly overhead Low angle of incoming sunlight Atmosphere North Pole 60º N 30º N Tropic of Cancer 0º (equator) 30º S 60º S South Pole Tropic of Capricorn
The seasons of the year result from the permanent tilt of the plant on its axis as it orbits the sun Figure 34.6B JUNE SOLSTICE (Northern Hemisphere tilts toward sun) MARCH EQUINOX (equator faces sun directly) DECEMBER SOLSTICE (Northern Hemisphere tilts away from sun) SEPTEMBER EQUINOX
What is a Biome? Plants and animals don't live in isolation, but they live together with other plants and animals in an interdependent group called an ecological community. If you think about it for a moment, you will realize that all of the plants and animals in a particular ecological community must be adapted to the same climate so that they can all live in the same location.
A distinct ecological community of plants and animals living together in a particular climate is called a "biome." Scientists have divided the broad spectrum of climates and ecological communities found on Earth into biomes in different ways - some with many divisions, some with only a few.
Major terrestrial biomes Figure º N Equator 30º S Tropical forest Savanna Desert Polar and high-mountain ice Chaparral Temperate grassland Temperate deciduous forest Coniferous forest Tundra (arctic and alpine)
Several types of tropical forests occur in the warm, moist belt along the equator Tropical Rainforest Tropical Rainforest Tropical forests cluster near the equator Figure 34.10
Drier, tropical areas and some nontropical areas are characterized by the savanna Tropical Savannah Tropical Savannah Savannas are grasslands with scattered trees Figure 34.12
Deserts are the driest of all terrestrial biomes –They are characterized by low and unpredictable rainfall Desert Desert Deserts are defined by their dryness Figure –Desertification is a significant environmental problem
Temperate grasslands are found in the interiors of the continents, where winters are cold –Drought, fires, and grazing animals prevent trees from growing –Farms have replaced most of North America's temperate grasslands Temperate grasslands include the North American prairie Figure 34.15
Temperate deciduous forests grow where there is sufficient moisture to support the growth of large trees Deciduous Forest Deciduous Forest –Nearly all of the original deciduous forests in North America have been drastically altered by agriculture and urban development Deciduous trees dominate temperate forests Figure 34.16
The northern coniferous forest, or taiga, is the largest terrestrial biome on Earth Taiga Taiga Coniferous forests are often dominated by a few species of trees Figure 34.17
The taiga is characterized by long, cold winters and short, wet summers Coastal coniferous forests of the Pacific Northwest are actually temperate rain forests
The arctic tundra lies between the taiga and the permanently frozen polar regions Arctic Tundra Arctic Tundra –It is a treeless biome characterized by extreme cold, wind, and permafrost –Permafrost is continuously frozen subsoil Long, bitter-cold winters characterize the tundra Figure 34.18