Title: Chapter 47: The Biosphere
1Chapter 47 The Biosphere
- Section 1
- Earth A Living Planet
2Earth A Living Planet
- Ecology is the study of the interactions of
organisms with one another and with their
physical surroundings - Scientists who study ecology are called
ecologists - Earth is a single living system, also known as a
biosphere, or living globe
3A fast-moving stream in Gatlinburg, TN is an
example of how organisms interact with one
another and with their physical surroundings. The
spray from the stream made it possible for mosses
to grow on the surfaces of nearby boulders
4Earth A Living Planet
- The biosphere is that part of the Earth in which
life exists - Includes all areas of land, air, and water on the
planet, as well as all the life that populates
these areas - Extends from about 8km above Earths surface to
as far as 8km below the surface of the ocean - Organisms are not distributed evenly throughout
the biosphere
5Ecosystems
- Because the biosphere is large, ecologists like
to work with smaller units called ecosystems - An ecosystem consists of a given areas physical
features (abiotic factors) and living organisms
(biotic factors) - Abiotic factors water, sunlight, soil type,
rocks, temperature, humidity, elevation, and
rainfall - Biotic factors fish, frogs, insects, snails,
worms, trees, ferns, lilies - The organisms living together in an ecosystem are
often referred to as a community
6Ecological Succession
- Ecosystems change over time because every
organism affects environmental conditions around
it - In the process of ecological succession an
existing community of organisms is replaced by a
different community over periods of time ranging
from a few decades to thousands of years
7Ecological Succession
- Sometimes succession occurs in places where no
living community existed before - When a new volcanic island arises from the sea,
its newly cooled lava contains no life - Organisms that colonize such areas are called
pioneer species - Succession can dramatically transform an
ecosystem - Over time, a lake or pond may fill up with silt
and organic matter, turning first into a marsh
and then into dry land
8Ecological Succession
- As physical factors change, living communities
also change - Succession can also occur in places where natural
disasters or human activities wipe out existing
communities - In much of the United States, for example,
abandoned farmland is colonized first by grasses,
then by other weeds, and later by shrubs and
small trees - Succession often leads to a fairly stable
collection of organisms called a climax community
9Ecological Succession
- An areas climax community is due partly to
chance - An ecosystem may eventually return to the way it
was after trees are cut down, land is dug up for
mining, or any other kind of environmental damage
occurs - But, it is also possible that succession will
take a different path and things will never be
the same again
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11Chapter 47 The Biosphere
12Land Biomes
- A biome is an environment that has a
characteristic climax community - The Earth is made up of two main types of biomes
land biomes and aquatic biomes - Most land biomes are named for their climax
community, or the dominant type of plant life
13Tundra
- Climate cold, long winters and cool, short
summers, with little precipitation - Yearly precipitation 10 inches
- Covers 1/5 of Earths land surface
- Annual precipitation is low
- H2O is unavailable most of the year
- Ground is permanently frozen
- Grasses, sedges, dwarf willows, mosses
- Foxes, reindeer, owls, caribou
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15Taiga
- Climate cool, short summers and cold, long
winters - Yearly precipitation 8 24 inches
- Ideal conditions for needle-leaved trees
- One of the largest biomes on Earth
- Marshes, lakes, and ponds are common
- Pine trees, fir trees, birch trees
- Elk, moose, deer, wolves, bears, wolverines
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17Temperate Deciduous Forests
- Climate warms summers and cool to cold winters
- Yearly precipitation 30 100 inches
- Trees shed their leaves in the fall
- Precipitation is distributed evenly throughout
the year - Contains humus ( a layer of decaying leaves and
twigs) - Deer, bears, beavers, raccoons, moose
- Oak trees, hickory trees, beech trees, shrubs
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19Grasslands
- Climate dry, hot summers and cold winters
- Yearly precipitation 4 24 inches
- Agricultural land
- Populated by herds of grazing mammals
- Impala, wildebeests, elephants
- Grasses, trees, shrubs, crops
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21Tropical Rain Forests
- Climate warm and moist, with little variation
in either rainfall or temperature - Yearly precipitation 100 inches
- Most diverse biome
- ½ of Earths species are here
- Most will be gone within 40 years
- Leads to the extinction of large numbers of
species - Lush plants, trees
- Butterflies, monkeys, insects
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23Deserts
- Climate very dry, often hot
- Yearly precipitation 8 inches
- Organisms have features that allows them to
conserve water - Vegetation is sparse
- Less than 5 of North America is desert
- Creosote brushes, cacti
- Roadrunners, kangaroo rats, kit foxes
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25Chapter 47 The Biosphere
26Aquatic Biomes
- Water ecosystems
- Includes freshwater, marine, and estuaries
- These biomes support more organisms than do the
land biomes - Some of the abiotic factors that affect the kinds
of organisms found in the aquatic biomes are
light intensity, amounts of oxygen and carbon
dioxide dissolved in the water, and the
availability of organic and inorganic nutrients
27Freshwater Biomes
- Rivers, streams, and lakes are considered the
freshwater biomes of the Earth - They provide much of our drinking water and are
an important source of food - Tiny floating plants and animals drift and swim
through the water - These organisms are eaten by fish and amphibians,
which also eat the vegetation and insects that
fall into the water from overhanging trees
28Freshwater Biomes
- Contains insects, fish, amphibians, reptiles, and
mammals - Unfortunately, people all over the world are
using rivers and lakes as dumping grounds for
wastes - The results of this carelessness are beginning to
catch up with us
29In swift-moving rivers, most organisms live in
the shallows, where algae and mosses cling to the
surfaces of rocks.
30Marine Biomes
- The vast habitats of the ocean, or the marine
biomes, cover most of the surface of Earth - Photosynthesis can only take place in the
uppermost region of a marine biome - This region is called the photic zone
- May be as shallow as 30m or as deep as 200m
- Phytoplankton and algae grow here
31Marine Biomes
- Oceanographers have divided marine biomes into
distinct zones based on their depth and distance
from the shore - Each of these zones contains organisms that are
adapted to the conditions there
32Intertidal Zone
- Most difficult zone for organisms to live in
- Must tolerate radical changes in their
surroundings - Once or twice a day they are submerged in ocean
water - The remainder of the time they are exposed to air
and sunlight - Organisms here have adapted in some way to the
pounding and crashing of waves - Some organisms burrow into the sand to keep from
being washed out to sea - Others attach themselves to rocks
33The intertidal zone is characterized by organisms
such as barnacles and starfish.
34Neritic Zone
- Extends from the low-tide line to the edge of the
open sea - Large seaweed are abundant here because this part
of the ocean is the photic zone - In shallow areas of tropical waters, meadows of
turtle grass provide food for fish,
invertebrates, and turtles - Along the ocean floor, lobsters and crabs crawl
while flounder and rays swim above them
35The neritic zone provides a home to brilliantly
colored coral-reef fishes.
36Open-Sea Zone
- Phytoplankton are responsible for 80-90 of the
Earths photosynthetic activity - Phytoplankton are eaten by larger animals
- Thus the chain of life in the sea begins with
these tiny organisms - Swimming rapidly through the open-sea zone are
fish of all shapes and sizes and mammals such as
dolphins and whales
37Open-Sea Zone
- Because nutrients are scarce in most of the open
sea, the growth of phytoplankton is relatively
slow - This limits the number of animals that can live
there - Closer to the shore, however, nutrients are more
abundant, and countless fish swim there to feed
and reproduce - Unfortunately, these rich fishing areas are much
more susceptible to pollution than is the open sea
38Deep-Sea Zone
- Area of high pressure, cold temperature, and
total darkness - This area is home to some of Earths strangest
creatures - Here, zooplankton wait for night in order to
migrate to the oceans surface and feed on
phytoplankton - Herds of bottom dwellers crawl along on the ocean
floor
39The deep-sea zone is home to some of the Earths
most bizarre creatures. The tube worms belong to
an ecological community whose ultimate source of
energy is chemicals from volcanic vents.
40Estuaries
- Estuaries are found at the boundary between fresh
water and salt water - Salt marshes, mangrove swamps, lagoons, and the
mouths of rivers that empty into the ocean are
examples of estuaries - Estuaries support a variety of life forms
- Because estuaries are usually shallow, sunlight
is able to penetrate the water completely
41Estuaries
- Photosynthesis occurs at all levels, making
estuaries a suitable environment for aquatic
plants - The abundance of such plants, in turn, supports
many types of fish, shrimp, and crabs - In fact, many fish and invertebrates spawn,
hatch, and nurse their young in estuaries - As the young mature, they head for open sea, then
return to the estuaries to reproduce - Several species of birds use estuaries for
nesting, feeding, and resting
42Estuaries are areas where fresh water and salt
water meet. This salt marsh in Long Island, New
York and the mangrove swamp in Florida are
examples of estuaries.
43Chapter 47 The Biosphere
- Section 4
- Energy and Nutrients Building the Web of Life
44Energy and Nutrients Building the Web of Life
- One of the most important factors in any
ecosystem is the flow of energy through the
ecosystem - Approximately ½ of the energy plants absorb from
the sun is used immediately - The rest is stored in plant tissues in the form
of carbohydrates - Animals that eat the plants obtain this energy
45Energy and Nutrients Building the Web of Life
- Energy cannot be recycled, or used again
- Thus energy in an ecosystem is referred to as a
flow rather than a cycle - Nutrients are generally recycled through an
ecosystem - When an animal dies, its matter does not
disappear - Rather, it decomposes and eventually gets used by
another organism
46Organisms are classified as producers, consumers,
or decomposers, depending on how they get their
food. Because spruce budworms feed directly on
the jack pine, which is a producer, they are
called primary consumers. Robins, which feed on
worms, are called secondary consumers.
Decomposers, such as mushrooms, get their food
from the remains of dead organisms.
47The Flow of Energy
- The sun is the ultimate source of energy for all
living things - Because photosynthetic organisms are able to make
their own food from inorganic substances, they
are called producers - Animals, on the other hand, are consumers
- Consumers get their energy either directly or
indirectly from producers
48The Flow of Energy
- Consumers that feed directly on producers are
called primary consumers - Herbivores
- Consumers that feed on primary consumers are
called secondary consumers - Carnivores
- Energy flows through an ecosystem from the sun to
producers and then to consumers
49The Flow of Energy
- When plants and animals in an ecosystem die,
their remains do not build up because of the
presence of decomposers - Decomposers are organisms that obtain their
energy from nonliving organic matter - Each step in this series of organisms eating
other organisms is called a trophic, or feeding,
level
50The Flow of Energy
- At each higher trophic level, less and less of
the energy originally captured by the producers
is available - Approximately 10 of the energy at one trophic
level can be used by animals at the next trophic
level - At each successive trophic level, less energy is
available to an organism
51Ecological Pyramids
- Ecologists use ecological pyramids to represent
the energy relationships among trophic levels - There are three types of ecological pyramids
- Pyramid of energy
- Pyramid of biomass
- Pyramid of numbers
52Pyramid of Energy
- A pyramid of energy shows the total amount of
incoming energy at each successive level
53Pyramid of Biomass
- The trophic levels of an ecosystem can also be
represented by a pyramid of biomass, which shows
the total mass of living tissue at each level
54Pyramid of Numbers
- Relationships among trophic levels may also be
represented by a pyramid of numbers - A pyramid of numbers illustrates the total number
of organisms at each level
55Biogeochemical Cycles
- Although energy moves in a one-way direction
through an ecosystem, nutrients are recycled - All organisms require certain essential nutrients
in order to grow - As members of each trophic level eat members of
the level beneath them, they acquire the complex
organic molecules and elements they need in
addition to energy - Nutrients move through the biosphere in a series
of physical and biological processes called
biogeochemical, or nutrient, cycles
56The Water Cycle
- The movement of water from the atmosphere to the
Earth and back to the atmosphere is called the
water cycle - The water cycle consists of an alternation of
evaporation and condensation - Water molecules enter the air by evaporation from
the ocean and other bodies of water - In the air, water molecules condense and then
return to the Earth in the form of precipitation
57The Water Cycle
- On land, most of the rainwater runs along the
surface of the ground until it enters a river or
stream that carries it to a larger body of water - Some water sinks into the ground and is called
groundwater - The upper surface of groundwater is known as the
water table
58The Water Cycle
59The Nitrogen Cycle
- All organisms require nitrogen to build proteins
- The movement of nitrogen through the biosphere is
called the nitrogen cycle - However, most of the nitrogen cannot be directly
used by living things - It must be converted into other forms
60The Nitrogen Cycle
- Certain bacteria that live on roots of plants
change free nitrogen in the atmosphere into
nitrogen compounds that can be used by living
things - Nitrogen fixation
- Once the nitrogen compounds are available, plants
use them to make plant proteins - Animals then eat the plants and use the proteins
to make animal proteins - When the plants and animals die, the nitrogen
compounds return to the soil
61The Nitrogen Cycle
- Eventually other bacteria in the soil break down
these nitrogen compounds into free nitrogen in a
process called denitrification - These bacteria are called denitrifying bacteria
- Through the process of denitrification, free
nitrogen is returned to the atmosphere
62The Nitrogen Cycle
63The Carbon and Oxygen Cycles
- The process by which carbon is moved through the
environment is called the carbon cycle - During photosynthesis, green plants and algae use
carbon dioxide from the atmosphere to form
glucose - Consumers and decomposers use glucose in
respiration, during which they produce carbon
dioxide - Carbon dioxide is then released into the
atmosphere, completing the carbon cycle
64The Carbon and Oxygen Cycles
- The movement of oxygen through the environment is
called the oxygen cycle - During photosynthesis, water molecules are split,
releasing oxygen into the atmosphere - The oxygen is used by most organisms for
respiration - During respiration, water is released
- The water is absorbed by plants, and the cycle
begins again
65The Carbon Cycle
66The Oxygen Cycle
67Nutrient Limitation
- The rate at which producers can capture energy
and use it to produce living tissue is controlled
be several factors, one of which is the amount of
available nutrients - If a nutrient is in short supply thus limiting
an organisms growth it is called a limiting
factor
68Feeding Relationships
- The simplest feeding relationship is a food chain
- In one food chain, a big fish eats little fish
that eat tiny fish that eat plankton - Nature is almost never that simple
- Instead of using a food chain, which only shows
one feeding level, ecologists use food webs - Food webs have many crisscrossing strands
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