The Biosphere

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The Biosphere

• Chapter 15

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What is the Biosphere?

• The biosphere is the part of Earth where life
  exists.
• All of Earths ecosystems, taken together, form
  the biosphere.

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Critical Thinking Activity Connecting Concepts

• Explain how feedback loops, such as those
  described in the Gaia hypothesis (pp. 457), might
  apply to predator-prey relationships.
• When a prey population increases in size, the
  predator population has more food to eat. As a
  result, the predator population increases in
  size. When the predators become so plentiful
  that the prey population decreases, the predators
  have less food to eat. As a result, the predator
  population decreases in size.

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Climate is the Prevailing Weather of a Region.

• The weather of an area may change from day to
  day, and even from hour to hour.
• In contrast, the climate is the long-term pattern
  of weather conditions in a region.
• Climate includes factors such as average
  temperature and precipitation and relative
  humidity.
• It also includes seasonal variations such as
  rainy or dry seasons, cold winters, or hot
  summers.
• A microclimate is the climate of a small specific
  place within a larger area.
• Microclimates are very important to living
  things.

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Earths Three Climate Zones
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Critical Thinking ActivityInferring

• Would areas along the shores of the Great Lakes
  have warmer summers and colder winters than other
  inland areas? Explain your reasoning.
• No, because of the buffering effects of the
  water, shoreline areas have moderate seasonal
  temperature changes compared to inland areas.

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Biomes

• A biome is defined by its climate and by the
  plant and animal communities that live there.
• A variety of different ecosystems are found
  within each biome.
• Earths major biomes include
• Tropical
• Grassland
• Desert
• Temperate
• Taiga
• Tundra

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Tropical Rain Forest Biome

• As little as 1 of the sunlight that strikes the
  uppermost branches of the canopy make it through
  to the ground in the tropical rain forest.
• The soil is very thin and low in nutrients
  because the large trees absorb available
  nutrients quickly from the ground.
• Predict what types of adaptations would be seen
  in the plant and animal life that dominate a
  tropical rain forest biome.

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Tropical Grassland Biome

• Tropical grasslands are found in the tropical
  climate zones of South America, Africa, and
  Australia.
• These grasslands are also called savannas.
• This biome is home to plants and animals that
  have adapted to the extreme shifts in moisture
  during the wet and dry seasons.

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Temperate Grassland Biome

• Fast spreading fires are common in temperate
  grasslands.
• Many of the plants in temperate grasslands have
  adapted to fire by producing fire-resistant seeds
  that require the fires heat to start
  germination.
• Predict how stopping fires might change a
  temperate grassland.

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Desert Biome

• Desert biomes receive less than 25cm (10 inches)
  of precipitation annually.
• There are four different types of deserts hot,
  semiarid, coastal, and cold.

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Temperate Deciduous Forest Biome

• A key feature of temperate biomes is their
  distinguishable seasons.
• This biome is characterized by hot summers and
  cold winters.
• Deciduous trees have adapted to winter
  temperatures by dropping their leaves and going
  dormant during the cold season.

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Temperate Rain Forest Biome

• The temperate rain forest does not receive
  precipitation evenly spread throughout the year.
• Coniferous trees, which retain their needles all
  year, dominate this biome.

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Taiga Biome

• The taiga (TY-guh) is also known as the boreal
  forest.
• Winters in the taiga are long and cold, often
  lasting six months or more.

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Tundra Biome

• Often described as bleak, the tundra is located
  beyond the taiga in far northern latitudes.
• Winter here lasts as long as 10 months per year.
• The ground below the surface is always frozen.
  This frozen ground is referred to as permafrost.

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Chaparral A Minor Biome

• Characterized by its hot, dry summers and cool,
  moist winters.
• Annual precipitation ranges from 15-40 inches,
  and occurs mostly during the winter as rain.
• Dominant plants are small-leaved evergreen shrubs
  many of which exhibit similar adaptations to
  plants found in desert biomes.
• Many chaparral plants have also adapted to the
  presence of fire, and some need fire in order for
  their seeds to germinate.
• Predict the types of animals that might be well
  adapted for life in the chaparral.

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Polar Ice Caps Mountains

• Polar ice caps and mountains are not considered
  biomes.
• Polar ice caps have no characteristic plant life.
  
• Mountains may exhibit the characteristics of
  several biomes.

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Critical Thinking Activity Connecting Concepts

• Male birds that migrate the earliest to their
  summer nesting sites can usually secure the best
  territories. What limiting factor keeps birds
  from arriving too early in the taiga?
• Temperature, because it dictates how much water
  is available for drinking and also the growth of
  food that birds rely on.

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Interactive Review Biomes

• http//www.classzone.com/cz/books/bio_07/resources
  /htmls/interactive_review/bio_intrev.html

Complete this interactive review using your
virtual textbook at home. Concept maps are an
excellent way to organize your thoughts and
review material!
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The Four Zones of the Ocean

• Intertidal Zone strip of land between high and
  low tides organisms in this zone must tolerate a
  variety of conditions that result from changing
  water levels and temperatures.
• Neritic Zone extends from the intertidal zone
  out to the edge of the continental shelf. These
  are highly productive marine areas.
• Bathyal Zone lies between depths of 200 and 2000
  meters has turbid water and fishes that have
  adapted to living in areas of high pressure.
  Many burrowing animals thrive here.
• Abyssal Zone complete darkness deep sea vents,
  only a few species can live here. Chemosynthetic
  organisms are at the base of the food chain here
  since sunlight is not available for
  photosynthetic phytoplankton.

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Life in the Neritic Zone

• Although it represents less than one-tenth of the
  total ocean area, it contains 40 times more
  biomass than the rest of the ocean.
• Much of the biomass is plankton, tiny
  free-floating organisms that live in the water.
• Phytoplankton are photosynthetic plankton. These
  organisms carry out the bulk of the
  photosynthesis on Earth, and therefore provide
  most of the oxygen. Seventy percent or more of
  the oxygen you breathe can be traced back to
  marine phytoplankton. These organisms also form
  the base of the oceanic food web.
• Zooplankton are animal plankton. They are the
  primary consumers of marine food webs.

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Coral Reefs Kelp Forests

• Coral reefs are found within the tropical climate
  zone. A single coral reef may be home to 400
  species of corals, along with hundreds of other
  species of fishes, sponges, and sea urchins.
• Corals have a mutualistic relationship with
  algae. The coral provide a home to the algae,
  and the algae provide nutrients for the coral.
• Kelp forests exist in cold, nutrient-rich waters.
  These are areas of high productivity that provide
  habitat and food sources to many marine species.
• Kelp is a seaweed that grows from the ocean floor
  up to the waters surface.

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Critical Thinking Activity Connecting Concepts

• How might the disappearance of coastal habitats
  affect an oceanic food web?
• Because many fish species spend an early stage of
  their lives in coastal habitats and many marine
  organisms feed on these and other coastal
  organisms, the disappearance of these habitats
  would be devastating to oceanic food webs.

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Interactive Review Marine Ecosystems

• http//www.classzone.com/cz/books/bio_07/resources
  /htmls/interactive_review/bio_intrev.html

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Estuaries are Dynamic Environments

• An estuary is a partially enclosed body of water
  formed where a river flows into an ocean.
• The distinctive feature of an estuary is the
  mixture of fresh water from a river and salt
  water from the ocean.
• These are highly productive ecosystems, on a
  level comparable to tropical rain forests and
  coral reefs.
• They provide the necessary habitat for a number
  of endangered and threatened species. The large
  number of phytoplankton and zooplankton in an
  estuary support a variety of species.
• Fish and crustaceans thrive here, as well as
  birds and other secondary consumers.
• The removal of estuaries can make coastal areas
  more vulnerable to flood damage from catastrophic
  weather events.
• In some areas of the US, over 80 of the original
  estuary habitat has been lost to land development.

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Critical Thinking ActivityInferring

• Estuaries occur where rivers flow into the ocean.
  What conditions in estuaries make them suitable
  as nurseries for organisms that live out in the
  open ocean as adults?
• Estuaries are rich in nutrients, and many feature
  outer reefs, sandbars, and barrier islands, which
  offer small organisms shelter.