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Climate and Biodiversity, Part 2. There Are Three Major Types of Forests  Forests are lands where the main form of plant is the tree.  Many forests.

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Presentation on theme: "Climate and Biodiversity, Part 2. There Are Three Major Types of Forests  Forests are lands where the main form of plant is the tree.  Many forests."— Presentation transcript:

1 Climate and Biodiversity, Part 2

2 There Are Three Major Types of Forests  Forests are lands where the main form of plant is the tree.  Many forests have been destroyed by logging or burning.

3 Tropical Rainforests  Tropical rainforests are found near the equator where hot, moist air rises and dumps its moisture.  The temperature year-round is very warm with high humidity and daily heavy rainfall.  Many plants can grow here because of all the water.  The main type of tree in the tropical rainforest is the broadleaf evergreen tree.  These trees keep their leaves all year.  The tops of the trees form a thick canopy that blocks most sunlight from reaching the forest floor.  There are very few plants on the rainforest floor.

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5  Some trees in the rainforest are draped with vines called lianas.  The vines reach up into the canopy and stretch from tree to tree.  This creates pathways for many rainforest animals.  If a large tree is cut down, its lianas can pull down other trees.

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7  Tropical rainforests have a very high net primary productivity (they produce a lot of plants, which do a lot of photosynthesis).  There is a very large amount of biodiversity in the rainforest.  50% of all the species of land plants and animals live in the tropical rainforest.  Rainforest plants have been found to contain chemicals that can be used to make prescription medication.

8  Rainforest species occupy specialized niches in distinct layers of the forest.  We say that the rainforest is stratified because it has these layers.  This allows all these species to avoid or minimize competition.

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10  The ground layer is the forest floor.  There is very little sunlight here, so there are very few plants.  Dead organisms and waste decompose very quickly because there are a lot of decomposers living here.  Many insects live here, so there are also many animals that eat insects like the giant anteater and the black- crowned antpitta.

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14  The shrub layer is just above the ground layer.  Small plants that do not need a lot of sunlight can live here.  Saplings that will eventually become tall trees are in the shrub layer.  Many house plants come from this layer.  The rainforest’s large predators live here, like the jaguar.  Apes, like gorillas and chimpanzees, live in this layer.

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17  The understory is the part of the rainforest just below the canopy.  It is still dark, so the trees grow large leaves to capture all the sunlight they can.  The trees in this layer grow to about 12 feet tall.  The animals that live here often live in the short trees and are good climbers.  Some animals that live here are spider monkeys, boa constrictors, and kinkajous.

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20  The canopy layer is the tops of the tall trees, that can reach 100 feet tall.  The canopy blocks the sun from reaching the layers beneath it.  The large leaves in the canopy prevent the heavy rain from pounding on the soil and washing it away.  Many of the trees in the canopy have air plants living on them.  Air plants grown on the branches of trees and absorb nutrients and water from the air, so they do not need soil.  The canopy is the busiest layer of the rainforest because most species live in the layer.  Animals that live here include cockatoos, sloths, toucans, and the golden lion tamarin.

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24  The emergent layer is the very tops of the tallest trees that break through the canopy.  These trees can be over 200 feet tall.  This layer receives the most sunlight.  The emergent layer is home to a third of the world’s bird species, like the harpy eagle and the macaw.  Primates like the gibbon live in the trees.  Other animals include the vampire bat and many species of butterflies.

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27  The soil in the rainforest is not very fertile.  Even though decomposition is fast, all the nutrients are immediately absorbed by the plants.  This leaves no nutrients in the soil.  People think that the large trees mean good soil, so they cut down the forests to build farms.  These farms fail.  At least half of the tropical rainforests on Earth have been destroyed or disturbed by humans.  There are only four areas with tropical rainforests left on Earth.  The Amazon rainforest in South America is the largest.

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29 Temperate Deciduous Forest  The temperate deciduous forest is cooler than the tropical rainforest.  These forests have warm summers and cold winters.  Deciduous trees lose their leaves in the winter.  This helps the tree save water during the cold winter when there may not be liquid water available.  Temperate forests have fewer decomposers than the tropical rainforest, so the falling leaves build up on the forest floor.  The leaves will decay slowly and release their nutrients slowly.

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31  New York City used to be a deciduous forest.  Animals that used to live here include deer, skunks, wild turkeys, porcupines, and coyotes.  We still see squirrels, raccoons, and opossums.

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34  Many of the world’s temperate forests have been degraded, mostly through logging and urban expansion.  The temperate forest has been degraded more than any other biome.  If given time, the temperate forest can grow back.  It takes about years.

35 The Taiga  Evergreen coniferous forests are also called the taiga.  The taiga is found just south of the arctic tundra.  It can also be found high on mountain slopes.  The taiga’s winter is very long and cold.  The Sun is only out for 6-8 hours a day.  The summers are short with cool to warm temperatures.  Summer can have 19 hours of sunlight.

36  The main type of tree in the taiga is the coniferous tree.  These are trees with cones, or evergreen trees like fir and pine.  Coniferous trees have small, needle-shaped, wax- coated leaves that they keep all year long.  The needles allow the tree to survive heavy snowfall.  Broad leaves would hold too much slow and make the tree branches break.

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38  Decomposition in the taiga is slow because of the cold.  Also, the needles from the trees are difficult to decompose because of their waxy covering.  Few small plants grow in the taiga because the soil is acidic.  The needles release an acid into the soil as they decompose, preventing other plants from growing.  Some animals like bears, wolves, moose, and lynx live year-round in the taiga.  During the summer, insect-eating birds like warblers migrate to the taiga.

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41 Temperate Rainforests  Temperate rainforests are found scattered along coastal areas that have a lot of rainfall.  These forests are often covered by a dense fog.  These forests have huge trees like redwoods and Douglas firs.  These forests used to be very common along the western coast of North America.

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45 Mountains Play Important Ecological Roles  Mountains are steep or high-elevated lands.  They cover about one-fourth of the Earth’s land surface.  On a mountain, large changes in altitude, slope, climate, soil, and plant life can happen over a very short distance.

46  About 1.2 billion people live in mountain ranges, and another 4 billion depend on mountain systems for their water.  Because of their steep slopes, mountain soils are easily eroded when their plants are removed.  The roots of the plants would normally hold the soil in place.  This could cause an avalanche or a landslide.

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48  Most of the world’s forests are found on mountains.  This means that most of the planet’s land species live on mountains.  Mountains are often homes to endemic species.  These are species that are found nowhere else on Earth.  Mountains play an important role in the water cycle by storing water as snow and ice.  During the summer, some of this snow and ice melt and enter rivers and lakes.

49 H OW H AVE H UMAN A CTIVITIES A FFECTED THE W ORLD ’ S T ERRESTRIAL E COSYSTEMS ?  Concept 1: In many areas, human activities are impairing ecological and economic services provided by the earth’s deserts, grasslands, forests, and mountains.

50 Humans Have Disturbed Most of the Earth’s Land  About 62% of the world’s terrestrial (land) ecosystems have been degraded or are being used unsustainably.  Many environmental scientists are calling for a global effort to save the Earth’s remaining wild biomes.  Many people do not want to do this because the biomes have valuable resources like lumber, fossil fuels, and minerals.

51 Humans Degrade the Desert  Humans build large cities in the desert.  These cities use the groundwater that is found under the desert.  The soil and underground habitats of the desert are destroyed by off-road vehicles.  There are many minerals under the desert and mining these minerals leads to pollution.

52 Humans Degrade the Grasslands  Many of the world’s grasslands have already been turned into farms.  In order to clear the grass to make the farm, people burn the grass and release carbon dioxide into the air.  Some grasslands are used as fields and are overgrazed by livestock.

53 Humans Degrade the Forests  Many forests have already been cut down to make room for farms, cities, and suburbs.  Some forests are used as tree farms where only one type of tree is grown.  This results in less biodiversity.  Forest streams can be polluted by nearby urban areas.

54 Humans Degrade the Mountains  The slopes and bottoms of mountains are cleared for farmland.  Mountains are mined for their minerals.  Air pollution can blow in from urban areas near mountains.


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