Threatened, Endangered and Extinct Species

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Threatened, Endangered and Extinct Species

• Standard 4.7

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How many species are on Earth?

• Scientists identified about 1.75 million
• Could be as many as 100 million
• Species can appear and disappear

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Extinction

• An extinct species is one that no longer exists.
• Extinction is a natural process.
• The rate of extinction is increasing due to human
  activities such as pollution.
• Removing organisms will change ecosystems.

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Effects of Extinction

• Causes a loss of animals that help cycle
  nutrients through the environment
• Lose plants that provide food and oxygen
• Loss of organisms that could supply new
  medications

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Biodiversity

• Biodiversity refers to the great variety of
  organisms on Earth
• Three major levels
• Genetic
• Species
• Ecosystem

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Biodiversity

• Also involves genetic variation within a
  particular species
• Human Examples
• Physical Traits hair color, height, eye color
  and susceptibility to disease

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Pennsylvanias Biodiversity

• More than 20,000 different species in PA
• Besides animals other common organisms in PA
  include
• Insects, plants, fungi and lichens
• Scientists in PA are trying to maintain
  biodiversity by listing and monitoring as many
  species as possible.

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Lichens
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Pennsylvanias Biodiversity
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Interactions Among Organisms

• Remember the food web all organisms rely on
  other organisms
• Predator-prey relationships help to keep an
  ecosystem in balance
• An organism of one species (the predator) eats a
  living organism of a different species (the prey)
• Examples polar bears eat fish, lions that eat
  zebras, robins that eat worms.

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Examples Predator-Prey
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Interactions Among Organisms

• As the prey population increases, ecosystems can
  support more predators
• As the prey population decreases, the lack of
  prey causes the predator population to decrease
• This allows for a stable carrying capacity
• This also allows the strongest and fittest
  members of the community to survive

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Other relationships

• Symbiosis organisms live closely together over
  a long period of time
• Can be parasitic, mutualistic, or commensalistic

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Other relationships

• Parasitism one species, the parasite, feeds on
  a second organism the host
• Parasite harms the host by living in or on it
• Examples ticks or mosquitoes that live off of
  the host
• Parasitism promotes ecosystem stability by
  preventing the populations of some organisms from
  becoming too large

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Parasitism Example
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Other relationships

• Mutualism both species involved in the
  symbiotic relationship benefit
• Examples
• Bees and flowers bees feed on flower nectar,
  and spread flower pollen in the process
• Lichens are two organisms, alga and fungus that
  grew together
• The algae undergo photosynthesis and provide food
  for the fungi and itself while the fungi gathers
  water and minerals to share with the algae

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Mutualism Example
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Other relationships

• Commensalism one organism benefits while the
  other is not affected
• Example Trees in the rain forest block sunlight
  from reaching the ground, therefore plants such
  as orchids establish roots high in tree branches,
  growing through the high canopy to reach sunlight
• The orchid can receive moisture and nutrients
  from the air and does not harm the tree

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The Human Impact

• When humans destroy habitats, kill off species or
  pollute the natural environment biodiversity
  often decreases
• As a result ecosystems break down

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Adaptations

• Adaptation special modification or
  characteristic that helps an organism better
  survive in its environment, and which typically
  develops over time or may be passed down from one
  generation to another
• Adaptations can be structural, or physical

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Structural or Physical Adaptations

• Examples desert plants with thick, wax-coated
  leaves
• Predator birds bald eagles have keen eyesight
  and are capable of flying at great speeds in
  order to catch prey

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Behavioral or Response Adaptations

• Example An animal that cannot regulate its
  internal temperature, such as lizards or snakes,
  sit in the sun on cool days to warm itself
• Retreats to its burrow on hot days to cool itself

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Structural Adaptations

• Structural adaptations - are physical
  characteristics that help an organism survive in
  its environment
• They help animals to perform basic tasks, such as
  moving or eating
• Examples Meat-eating animals have sharp
  incisors for killing prey
• Plant eating animals have large, flat teeth that
  allow them to grind plants into pieces that are
  easily swallowed

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Structural Adaptation Examples

• Animals in deserts thousands of miles apart have
  the same types of adaptations
• Plants that grow in the deep shade of forests
  have dark green leaves that increase their
  ability to catch any light that reaches the
  forest floor
• Chameleon is a lizard that changes its color to
  match its surroundings at the time

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Chameleon
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Butterflies

• Mimicry an adaptation in which one species
  copies the appearance or behavior of another
  species
• Recall the Animal Camouflage Article
• Viceroy butterfly protects itself by looking like
  the monarch butterfly, which birds avoid because
  of their bad taste

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Adaptation Advantages

• Decreases competition
• Allows species niche to be different
• Allows species survival

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Behavioral Adaptations

• The way an organism acts or responds to its
  environment in order to survive
• Can be reflexive or instinctive

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Reflexive Behaviors

• A behavior that is triggered automatically by
  something outside an organism
• The behavior happens without the organism
  thinking about it
• Example Pulling your hand off of something hot
• Example Running from a loud noise

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Instinctive Behaviors

• A behavior that an organism carries out because
  it is genetically prone to do so
• These are natural reactions
• Examples Traveling in a group (safety in
  numbers)
• To look bigger and more frightening a blowfish
  expands its body with air
• Male bioluminescent fireflies flash light to
  attract females

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Other Adaptations

• Hibernation animals decrease their activity
  during winter months after constant eating during
  the fall
• Estivation to avoid the heat of summer some
  frogs, lizards and ground squirrels sleep through
  the summer in a dormant state

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Other Adaptations

• Migration allows animals to find more favorable
  climates or feeding conditions after a change in
  climate

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Courtship Rituals

• Instinctive behaviors because they encourage
  animal reproduction
• Male birds use songs to attract female birds
• Structural adaptations
• Male peacock struts using his colorful tail
  feathers so females will notice him

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Survival of the Fittest

• Which will survive in the snowy climate of
  northern Alaska?
• White rabbit with long thick fur or
• Gray rabbit with short fur

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Natural Selection

• Most helpful traits are passed on to future
  generations Charles Darwin
• Process that makes it more likely that organisms
  with the best characteristics for survival in a
  specific environment will survive, reproduce, and
  pass on their advantageous genetic traits to
  offspring

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Populations

• In order to evolve so the most advantageous
  adaptations become common three things must
  happen
• Trait must vary within the species
• The adaptation must be one that parents can pass
  on to offspring genetically
• One version of the adaptation must benefit the
  members to that they survive and reproduce more
  than the members who do not have it
• May occur quickly or take millions of years

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Amazing Adaptations

• Ice fish
• Evolved to have no red blood cells and no
  hemoglobin
• Oxygen dissolves in the blood
• Allows fish to survive in the extreme cold

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Human Impact

• Negative
• Destroying habitat
• Polluting rivers, lakes

• Positive
• Repair damage already done
• Protect whole ecosystems (conserve plants and
  animals)
• Maintain biodiversity
• Wildlife refuges
• Protect endangered species

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Protecting Endangered Species

• Government protected habitats
• Bred in captivity and then returned to wild
• Examples bald eagle, California condor
• Restrictions to hunting

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Bald Eagle

• In 1700s population of 100,000 in 1970 population
  of less than 3,000
• Cause unregulated hunting and habitat
  destruction, DDT pesticide
• DDT caused eagles to produce eggs with shells
  that were too thin
• Solution Government protected eagles nest,
  bred in zoos, banned use of DDT
• Population increased but still endangered

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Bald Eagle
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PABS

• Pennsylvania Biological Survey (PABS)
• Helps to maintain states biodiversity
• Tracks and monitors plants and animals
• Coordinates programs, surveys and research on PA
  wildlife
• Developing bio-reserves throughout PA
• Help conserve ecosystems throughout the state

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Endangered Species Act

• ESA US law that governs the protection of
  species whose populations are in decline and
  could be in danger of extinction
• The law forbids hunting, killing, collecting or
  harming of species listed as endangered or
  threatened.
• 3 categories
• Threatened, Endangered, Extinct

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ESA Categories

• Threatened
• A species that still has many individuals in the
  wild but whose numbers are dwindling to a point
  at which the species could become endangered
• Example Green snake

• Endangered
• A species that has so few individuals remaining
  that extinction is a possibility in the near
  future
• Example Delmarva fox squirrel

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ESA Categories

• Extinct
• A species that no longer exists
• Example Passenger pigeon

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Factors Prone to Extinction

• Specific food requirements
• Specific habitat or nesting requirements
• High on food chain or food web
• These animals are more vulnerable to pollution
• Migration
• Reproduce a low rate
• Limited habitat range
• Interference with human activities

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Help for Species in Danger

• National Marine Fisheries Service and US Fish and
  Wildlife Service
• Propose species the ESA will protect
• Can delist species if species is no longer in
  need of protection
• Happened to bald eagle in 1999
• Humans have accelerated extinction between 1,000
  and 10,000 times