Ch. 12

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Ch. 12

• Interaction of Life

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Living Earth

• Biosphere The part of the earth that supports
  life
• Includes the top portion of earths crust, all the
  waters that cover earths surface, and the
  atmosphere that surrounds earth
• The biosphere is made up of different
  environments that are homes to different
  organisms
• These different environments are called Biomes

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Biome 1 Aquatic

• The aquatic biome can be broken down into two
  basic regions, freshwater (i.e, ponds and rivers)
  and marine (i.e, oceans and estuaries).
• Freshwater is defined as having a low salt
  concentrationusually less than 1.
• There are different types of freshwater regions
  ponds and lakes, streams and rivers, and
  wetlands.

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Wetlands

• Wetlands are areas of standing water that
  support aquatic plants.
• Marshes, swamps, and bogs are all considered
  wetlands.
• Plant species adapted to the very moist and
  humid conditions are called hydrophytes.
• These include pond lilies, cattails, sedges,
  tamarack, and black spruce.
• Wetlands have the highest species diversity of
  all ecosystems. Many species of amphibians,
  reptiles, birds (such as ducks and waders), and
  furbearers can be found in the wetlands.

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• not always covered by Water
• Water Table is near or above the surface of
  Wetland
• Two Types coastal (also known as tidal or
  estuarine wetlands) and inland (also known as
  non-tidal, freshwater (Everglades)

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Biome 2 Deserts

• Deserts cover about one fifth of the Earths
  surface
• rainfall is less than 50 cm/year. Warm Weather
  Desert - Sahara of North Africa and the deserts
  of the southwestern U.S., Mexico, and Australia,
  occur at low latitudes,
• cold deserts, occur in the basin and range area
  of Utah and Nevada and in parts of western Asia.
• Most deserts have a considerable amount of
  specialized vegetation, as well as specialized
  vertebrate and invertebrate animals

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Biome 3 Forest

• Today, forests occupy approximately one-third of
  Earths land area,
• account for over two-thirds of the leaf area of
  land plants,
• and contain about 70 of carbon present in living
  things
• There are three major types of forests, classed
  according to latitude
• tropical
• temperate
• boreal forests (taiga)

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• Tropical
• Tropical forests are characterized by the
  greatest diversity of species.
• They occur near the equator.
• winter is absent, and only two seasons are
  present (rainy and dry). The length of daylight
  is 12 hours and varies little.
• Temperature is on average 20-25 C and varies
  little throughout the year
• Precipitation is evenly distributed throughout
  the year, with annual rainfall exceeding 2000 mm.

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• Soil is nutrient-poor and acidic. Decomposition
  is rapid and soils are subject to heavy leaching.
• Canopy in tropical forests is multilayered and
  continuous, allowing little light penetration.
• Flora is highly diverse one square kilometer may
  contain as many as 100 different tree species.
  Trees are 25-35 m tall, and shallow roots,
  mostly evergreen, with large dark green leaves.
  Plants such as orchids, bromeliads, vines
  (lianas), ferns, mosses, and palms are present in
  tropical forests.
• Fauna include numerous birds, bats, small
  mammals, and insects.

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Jaguar
Orangutans
Caiman
Tree Frog
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• Temperate forests
• occur in eastern North America, northeastern
  Asia, and western and central Europe.
• Well-defined seasons with a distinct winter
  characterize this forest biome.
• Moderate climate and a growing season of 140-200
  days during 4-6 frost-free months distinguish
  temperate forests.
• Temperature varies from -30 C to 30 C.
• Precipitation (75-150 cm) is distributed evenly
  throughout the year.

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• Soil is fertile, enriched with decaying litter.
• Canopy is moderately dense and allows light to
  penetrate, resulting in well-developed and richly
  diversified understory vegetation and
  stratification of animals.
• Flora is characterized by 3-4 tree species per
  square kilometer. Trees are distinguished by
  broad leaves that are lost annually and include
  such species as oak, hickory, beech, hemlock,
  maple, basswood, cottonwood, elm, willow, and
  spring-flowering herbs.
• Fauna is represented by squirrels, rabbits,
  skunks, birds, deer, mountain lion, bobcat,
  timber wolf, fox, and black bear.

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• Boreal forests, or taiga,
• represent the largest terrestial biome. Occuring
  between 50 and 60 degrees north latitudes, boreal
  forests can be found in the broad belt of Eurasia
  and North America
• Seasons are divided into short, moist, and
  moderately warm summers and long, cold, and dry
  winters.
• The length of the growing season in boreal
  forests is 130 days.
• Temperatures are very low.
• Precipitation is primarily in the form of snow,
  40-100 cm annually.

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• Soil is thin, nutrient-poor, and acidic.
• Canopy permits low light penetration, and as a
  result, understory is limited.
• Flora consist mostly of cold-tolerant evergreen
  conifers with needle-like leaves, such as pine,
  fir, and spruce.
• Fauna include woodpeckers, hawks, moose, bear,
  weasel, lynx, fox, wolf, deer, hares, chipmunks,
  shrews, and bats.

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Biome 4 Grasslands

• Grasslands are characterized as lands dominated
  by grasses rather than large shrubs or trees.
• There are two main divisions of grasslands (1)
  tropical grasslands, called savannas, and (2)
  temperate grasslands

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• Savannas
• Savanna is grassland with scattered individual
  trees.
• Savannas of one sort or another cover almost half
  the surface of Africa (about five million square
  miles, generally central Africa) and large areas
  of Australia, South America, and India.
• . Savannas are always found in warm or hot
  climates where the annual rainfall is from about
  50.8 to 127 cm (20-50 inches) per year.

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• It is crucial that the rainfall is concentrated
  in six or eight months of the year, followed by a
  long period of drought when fires can occur.
• Savannas receive an average annual rainfall of
  76.2-101.6 cm (30-40 inches). However, certain
  savannas can receive as little as 15.24 cm (6
  inches) or as much as 25.4 cm (10 inches) of rain
  a year.

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• Temperate Grasslands
• Temperate grasslands are characterized as having
  grasses as the dominant vegetation.
• Trees and large shrubs are absent.
• Temperatures vary more from summer to winter,
  and the amount of rainfall is less in temperate
  grasslands than in savannas.

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• Precipitation in the temperate grasslands usually
  occurs in the late spring and early summer.
• The annual average is about 50.8 to 88.9 cm
  (20-35 inches). The temperature range is very
  large over the course of the year. Summer
  temperatures can be well over 38 C (100 degrees
  Fahrenheit), while winter temperatures can be as
  low as -40 C (-40 degrees Fahrenheit).

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Biome 5 Tundra

• is the coldest of all the biomes.
• It is noted for its frost-molded landscapes,
  extremely low temperatures, little precipitation,
  poor nutrients, and short growing seasons.
• Dead organic material functions as a nutrient
  pool.
• The two major nutrients are nitrogen and
  phosphorus.
• Nitrogen is created by biological fixation,
• and phosphorus is created by precipitation.
• Tundra is separated into two types arctic
  tundra and alpine tundra.

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• The growing season ranges from 50 to 60 days.
• The average winter temperature is -34 C (-30
  F), but the average summer temperature is 3-12 C
  (37-54 F) which enables this biome to sustain
  life.
• Rainfall may vary in different regions of the
  arctic.
• Yearly precipitation, including melting snow, is
  15 to 25 cm (6 to 10 inches).
• Soil is formed slowly.
• A layer of permanently frozen subsoil called
  permafrost exists, consisting mostly of gravel
  and finer material.

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Musk Oxen
Snow Owl

Arctic Fox
Polar Bear
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Ecosystems

• The amount of energy received by the sun makes
  the temperature just right for life to exist
• An ecosystem consists of all the organisms living
  in an area and the nonliving features of their
  environment
• Nonliving features Water, temperature, sunlight,
  soil, and air
• Ecology is the study of the interaction that
  occurs between living and nonliving features

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• Population
• Population is made up of all the organisms in an
  ecosystem that belongs to the same species
• Ecologist often study how populations interact
• This is called the community
• Community refers to all the different populations
  in an ecosystem

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• Habitats
• The place in which an organism lives is called
  its habitat
• Trees would be a birds habitat
• Forest floor would be a salamanders habitat
• An animals habitat provides the kinds of food and
  shelter, the temperature, and the amount of
  moisture the organism needs to survive

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Population

• Competition occurs when two or more organism seek
  the same resource
• Organism compete for
• Food
• Water
• Living space
• Mates

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• Competition Limits population size
• Competition for food, living space, or other
  resources can prevent population growth
• Most intense competition in nature is usually
  between organisms of the same species
• Competition also takes place among individual of
  different species

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contest among organisms for the limited resources
of an ecosystem                              
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• Population sizeindicates whether a population is
  healthy and growing
• 1. Population densitythe size of a population
  that occupies a specific area
• 2. Two ways to measure the size of a wildlife
  population
• a. Trap-mark-release method
• b. Sample count method

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• 3. Elements that affect population size
• a. Limiting factorany living or nonliving
  feature that restricts the number of individuals
  in a population
• b. Carrying capacitythe largest number of
  individuals of one species that an ecosystem can
  support
• c. Biotic potentialthe maximum number of
  offspring that parent organisms can produce
• d. Birth and death rates
• e. Movement of organisms into or out of an area

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• Exponential growththe larger a population
  becomes, the faster it grows
• After population grows so large it slows and the
  number of organism remains fairly constant
  (reaches equilibrium)
• The ecosystem has reached its carrying capacity

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                                                                                                                   Simply stated Every living organism has to eat.  When organisms eat - they reproduce.  Assuming generation overlap, the population will grow.  As food availability increases, a population will increase -- tracking its food availability.
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• Earths human population shows exponential growth
• In the year 2000, earths human population
  exceeded 6 billion people
• By the year 2050 earths population could reach 10
  billion

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• Discussion Question
• If a population were decreasing, what kinds of
  questions would an ecologist ask to determine the
  problem?

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• Are there any limiting factors?
• Are there enough food, water, living space, and
  mates available?
• Has the population reached its carrying capacity?
  
• Does the population have a low biotic poten-tial?
• Is something causing the death rate to increase,
  or the birth rate to decrease?
• Are organisms moving out of the area?

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Interactions within Communities
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Obtaining energy

• The energy that fuels life on earth is derived
  from the sun
• Producers (plants) carry out photosynthesis to
  produce energy rich molecules (glucose Sugar)
• Glucose molecules serve as food
• Made up Carbon, oxygen, and hydrogen
• When this molecules break apart (in digestion)
  they release energy to fuel life processes

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• Producers
• Most producers contain a green pigment called
  Chlorophyll (Absorbs Sunlight)
• Some producers makes energy-rich molecules
  through a process called Chemosynthesis.
• Found near volcanic vents
• Use inorganic substances from the water

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• Consumers
• Cannot make their own food
• Make energy by eating other organisms
• Four categories of consumers
• Herbivores eat nothing but plants
• Rabbits, deer, cows, horses
• Omnivores Eat both plants and animals
• Pigs, humans, bears
• Carnivores eat other animals
• Spiders, frogs, lions, tigers
• Decomposers consume waste and dead organisms,
  helps recycle once living material
• Fungi, earthworms, and bacteria

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Herbivores
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Carnivores
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Food Chains

• Shows how organism depend on each other
• Show the feeding relationship in an ecosystem
• Plants are producers
• Herbivore Primary consumer
• Carnivores Secondary , tertiary, quaternary and
  so on

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Symbiotic Relationships

• Not all relationships among organisms involve
  food
• Many live together and share resources in other
  ways
• 3 Examples
• Mutualism
• Commensalisms
• Parasitism

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• Mutualism
• Relationship in which both organisms benefit
• Pollination by birds and insects
• Transportation of seed by bird and other animals
• Coral and Dinoflagellates
• Ants and Aphids
• Lichens Alga supplies energy for itself and the
  fungus, the fungus provides a protested space
  where it can grow

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Lichen
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Coral
Dinoflagellates
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• Aphids are small, soft-bodied, near defenseless
  insects that feed on plant sap. They feed by
  inserting a pointed, strawlike mouth structure
  called a stylus into the vascular tissues
  (internal piping) of the plant and sucking the
  plant juices out. Plant sap, a combination of
  water and sugars, is low in other nutrients,
  however, and the aphid must process a great deal
  of plant sap in order to get the amino acids and
  other nutrients it needs. Most of the sugars and
  water, therefore, are excreted as waste through a
  pair of structures called cornicles located near
  the rearend of the insect. If you own a car and
  have parked it under a tree during the summer,
  the sticky sap you find on the car is likely to
  be the waste plant sap produced by aphids.
• Some ant species use this excess plant sap for
  their own nutrition. Ants find a colony of aphids
  and milk the waste plant sap from the cornicles.
  In return the ants protect the aphids from
  predators and parasites. In some cases ants tend
  colonies almost like ranchers with their cattle,
  not only protecting the aphids, but moving them
  around from plant to plant.

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A remarkable 3-way mutualism appears to have
evolved between an ant, a butterfly caterpillar,
and an acacia in the American southwest. The
caterpillars have nectar organs which the ants
drink from, and the acacia tolerates the feeding
caterpillars. The ants appear to provide some
protection for both plant and caterpillar.
Research of Diane Wagner, American Museum of
Natural History Southwestern Research Station
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• Commensalism
• A symbiotic relationship in which one organism
  benefits and the other is not affected
• Clownfish and a sea anemone
• Remora and shark
• Egret and Cattle / Horses

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The relationship between these the sea anemone
and the clownfish has been a much studied topic.
As far as is known, the fish is able to produce a
special mucus that causes the anemone not to
release its stings. It is also believed that the
movements of the fish inform the anemone of its
identity. In return for the anemone's protection,
the fish brings scraps to it, and lures larger
fish into the anemone's tentacles.
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• The egrets tended the cattle daily from soon
  after sunrise until late afternoon. The number of
  cattle egrets observed with each animal varied
  but commonly averaged two per animal. Egrets
  walked very near the cattle, picking insects from
  the animals and surrounding vegetation. They
  pecked horse flies and other nuisance flies from
  the cattle's lower extremities and regularly
  perched upon the animals backs to feed. The
  cattle did not appear belligerent nor disturbed
  by the presence of the egrets. In fact, the
  cattle apparently encouraged the egrets'
  association by moderating tail-switching and
  other "fly fighting" behavior while egrets were
  feeding on their backs.

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Cattle Egrets
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• A remora is a fish that has kind of a suction
  disk on the top of its head. By means of this
  disk, it attaches itself to some large sea
  animal, often a shark. The effect on the shark is
  probably neutral but the remora benefits. First
  it uses very little energy in moving about
  because it is carried by the shark. Secondly, it
  swallows pieces of the shark's prey that float
  by. This kind of relationship - in which one
  organism is benefited and the other is unaffected
  -

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                                                I
mperial shrimp hitching a ride on a Sea-cucumber
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Parasitism

• A symbiotic relationship when the host organism
  is harmed
• Roundworms (Ascaris)
• Flatworm (Tapeworm)
• Lice
• Ticks
• Hookworm

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Human Flea
Head Lice
Deer Tick
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Tapeworm
Can reach lengths of 25 meters
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Hookworm