Population Biology Biological Diversity

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Population BiologyBiological Diversity
Conservation
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Population Growth

• An increase in the size of a population over time.

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Population Growth Rate

• Population growth is not Linear.
• Example of Linear growth
• 5.00/hour, 1hr 5.00, 2hr 10.00
• 3hr 15.00, 4hr 20.00.

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Population Growth is Exponential

• Starts out slow ends up fast.
• Do Problem Solving Lab 4-1 page 99.

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Limits of Exponential Growth

• All populations have the potential to grow
  exponentially.
• What prevents the world from being overrun will
  all kinds of living things?

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• Through population experiments, scientists have
  found limits to population growth.
• Limiting factors such as food or space, cause
  populations to stop increasing.

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Carrying Capacity

• The number of organisms of one species that an
  environment can support.

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• When populations exceed the carrying capacity
  deaths exceed births.
• When populations are under the carrying capacity
  births exceed deaths.

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Patterns of Population Growth

• Why are mosquitoes more abundant at certain times
  of the year?
• Why dont they reach carrying capacity and become
  stable?

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• Mosquitoes reproduce very rapidly and produce
  many offspring.

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Unstable Environments

• Organisms in unstable environments live in an
  unpredictable and rapidly changing areas,
  therefore they have to be able to grow and
  reproduce quickly.

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• Typically, these organisms have small body size,
  mature rapidly, reproduce early, and have a short
  life span.

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• Once conditions change to unfavorable they die
  out. The small surviving populations will
  increase exponentially when conditions are again
  favorable.

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Stable Environments

• Elephants, Humans, Bears, Whales, and long lived
  plants are large and reproduce slowly. These
  organisms maintain populations near the carrying
  capacity of their environments.

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• Rapid life history patterns are found in
  unpredictable environments.
• Long life history patterns are found in stable
  environments.

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Environmental Limits to Growth

• Limiting Factors can be either Biotic or Abiotic.
• Two Kinds of Limiting Factors...

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Density-dependent Factors

• Include Disease, Competition, Parasites, and
  Food.
• These have an increasing effect as the population
  increases.

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EXAMPLE

• Disease spreads more rapidly in populations where
  its members live close together.
• Smaller populations usually live farther apart,
  so it is harder for the disease to spread.

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Density-independent Factors

• Include Floods, Droughts, Earthquakes,
  Hurricanes, Bombs, Very Cold Long Winters, etc.
• Affect all populations, regardless of their
  density.

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EXAMPLE

• Hurricane Mitch, hits south Florida. Does
  extensive damage to both densely populated areas
  as well as sparsely populated areas.

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Organism Interactions Limit Population Size

• Predator - Prey
• Competition
• Over Crowding

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Predator-Prey Relationships

• Lynx eat Hares.
• If Hares get eaten they can not reproduce.
• This means less Hares.

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• Less Hares means Lynx starve and die.
• Less Lynx means Hares can reproduce.
• This means more Hares.

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• Lynx eat Hares.
• If Hares get eaten they can not reproduce.
• This means less Hares.

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• Less Hares means Lynx starve and die.
• Less Lynx means Hares can reproduce.
• This means more Hares.

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• Lynx eat Hares.
• If Hares get eaten they can not reproduce.
• This means less Hares.

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• Less Hares means Lynx starve and die.
• Less Lynx means Hare can reproduce.
• This means more Hares.

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Benefits of Predation

• Usually in Prey populations the young, old or
  injured members are caught.
• Predation helps improve the odds that there will
  be sufficient resources for the healthiest
  individuals in the population.

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Competition

• Density-dependent factor
• Within a population members compete for food,
  shelter, mates, etc.

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• The smaller the population the greater the
  resources thus competition is low.
• The larger the population the fewer the resources
  increasing competition.

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Play Habitat lab sit Oh Deer
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Over Crowding

• When populations or organisms become crowded,
  individuals may exhibit stress.

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• Populations of rats and mice when crowded exhibit
  aggression, they fight and kill one another, eat
  the babies, decreased parental care, decreased
  fertility, and decreased resistance to disease.

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• Homework SA 4.1 pg 103 and CA4
  1,2,3,5,7,8,11,12,14,16,18,20,23,24,25.
• Page 111

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Bio-diversity

• Refers to the variety of life in an area.
• Canada 163 species of mammals
• United States 367 species of mammals
• Mexico 439 species of mammals

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• The trend shows a greater bio-diversity as you
  move toward the equator.

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• The richest environments for bio-diversity are
  all warm places, Tropical rain forests, coral
  reefs, and large tropical lakes.

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Importance of Biodiversity

• Esthetically pleasing.
• Parking lot vs Mountain Vista

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Why Else is it Important?

• Life Depends on Life.
• Predators keeps populations in check.
• Plants depend on pollinators.

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• Animals could not exist without green plants.
• Plants need decomposers to break down dead
  material into nutrients they can use.

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• A pest can easily destroy all the corn in a
  field.
• Its much harder to completely destroy a single
  plant species in a forest, because the plant
  could exist in many different parts of the forest.

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• The fewer the number of species in an ecosystem
  the easier it is to disrupt life in that
  ecosystem.

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Important to Humans

• Oxygen is supplied and removed by plants and
  algae.
• Give us a diverse diet.
• Building materials
• Clothing

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• Almost all drugs were first found in plants,
  before being made synthetically.
• Pennicillium, antibiotic, mold.
• Antimalarial drug quinine, tree bark.

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• Aspirin, willow bark.
• Drugs for treatment of leukemia, Rosy periwinkle.
• Taxol, anti cancer drug, Pacific yew tree.

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• Preserving biodiversity ensures there will be a
  large supply of living things to provide for the
  future.

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Loss of Biodiversity

• Extinction the disappearance of a species when
  the last of its members dies.
• Natural process, however humans usually speed it
  up.

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• Since 1980 almost 40 species have become extinct.
• Threatened species When a population rapidly
  declines.

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• 1970s about 3,000,000 wild elephants.
• 1990s about 700,000 wild elephants.

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• Endangered species Species numbers become so
  low that extinction is very likely.
• California condor, Florida manatee, Black rhino,
  Siberian tiger, hard working student.

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United States

• Extinct 179
• Critically Endangered 235
• Endangered 179

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Threats to Biodiversity

• 8 main reasons biodiversity is being threatened.

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1 Habitat loss

• Rain forest is made into a pasture.
• Meadow is made into a parking lot.
• Swamp is drained for a subdivision.

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• Habitat loss is the number 1 threat to
  biodiversity.
• Once the habitat is gone the organisms either die
  or have to move.

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2 Habitat fragmentation

• Roads. Fences, Cities cut across our wilderness.
• This separates the wilderness thus preventing
  species from thriving.

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• Smaller wilderness areas support less life.
• Do PSL 5-1 page 119.

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Biotic issues

• Large predators cannot obtain enough food in
  small wilderness areas.
• Bears need vegetative cover in order to survive.
  They hate to be in the wide open.

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Abiotic issues

• Habitat fragmentation can change the climate of
  the area.
• Cut the trees down, more sun exposure, less
  moisture.

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3 Habitat degradation

• Damage to the habitat by pollution.
• 3 main kinds of pollution
• Air, Land , Water.

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4 Acid Rain

• SO2 from coal burning factories.
• NO, NO2 for cars and trucks.
• Now in the air dissolves into the water vapor in
  the clouds.
• Turns to acid.

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• When it rains the land is now covered with acid.
• The acid begins to kill the lakes and the plants.

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5 Ozone layer depletion

• We use CFCs which destroy the ozone layer. This
  lets in more UV radiation from the sun.
• More frogs and toads are being born with
  deformities than before.

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6 Water pollution

• Fertilizers, animal waste, gets into a pond,
  lake, river etc. causes a algal bloom. As the
  algae dies it decays removing O2 from the water
  killing all other life in water.

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• Litter in the water also affects wildlife.
• Sea turtles get tangled in plastic soda pop ring
  holders.
• Eat plastic (look like jelly fish).
• Caught in old nets.

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7 Land Pollution

• The average person produces 3.96 lbs. of solid
  waste daily. This is 1445.4 lbs. Yearly.
• In the US there is 1,131,944,976 lbs of solid
  waste produced daily.

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• DDT and other insecticides pollute the land.

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8 Introduction of Exotics

• Exotic - Any plant or animal that is not native
  to the area.
• Goats to Santa Catalina island destroyed 48
  native plants.
• Sea lamprey into the great lakes. (Erie canal)

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• Russian cheet grass to the US.
• Dyers woad in Utah.

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• Since they are not native to the area they
  usually do not have any natural predators. They
  grow unchecked and usually take over the are
  killing off the native species.

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• Show Video
• Help Save the Planet Earth
• Homework page 124 problems 1-5.

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Conservation Biology

• Field of Biology that studies methods and
  implements plans to protect biodiversity.

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• 1973 President Nixon signed into law the
  ENDANGERED SPECIES ACT.
• This law made it illegal to harm any species on
  the endangered species list.

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• Harm includes changing an ecosystem where
  threatened species live.

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CITES

• Convention on International Trade in Endangered
  Species. Group of 120 countries that prohibit
  and control the trade of endangered species.

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Preserving habitats

• In 1872 the first National Park was created.
• Yellowstone
• The park system has been created to preserve and
  protect wildlife and unique geology.

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• In 1872 Elk, Bear, Moose, and bison were widely
  distributed across the U.S. as far east as
  Pennsylvania.

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• Now their range is almost reduced to only the
  National Parks and National Forest Land.

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• In Zaire, Africa, only 3.9 of the land is
  protected but 89 of the bird population is found
  there!

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• Only 6 of the Earths land surface is protected.

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Sustainable use

• A concept that allows people to use the resources
  of the wilderness areas in ways that will not
  damage the ecosystem.

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Conservation Groups

• Groups that raise money and purchase land that is
  then set aside for protection.

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• What would be the best strategy for purchasing
  land? One big 1000 acre plot or Ten 100 acre
  plots?

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Habitat corridors

• Natural strips that allow the migration of
  organisms from one area to another.
• Help overcome some of the problems of habitat
  fragmentation.

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Reintroduction programs

• Release organisms into an area where their
  species once lived.

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• Brown pelican - DDT caused the birds to
  completely disappear from around the shores of
  the Gulf of Mexico.

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• After DDT was banned, 50 Birds were reintroduced
  from Florida.
• Today there are 7000 birds.

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• Do PSL 5.2 page 128.

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Captivity

• An organism that is held by people.
• Ginkgo trees - Thought to be extinct.
• Found in a Chinese monastery.

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• Today the Ginkgo is found in all most all
  metropolitan areas in the U.S.
• California Condor and Arabian oryx.

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• Watch video Common Ground.
• Do SA 5.2 page 129 1-5.
• CA 5 1-25. Page 133-135.
• Vocab Due on day of test.