Transcript Adaptation or Extinction! - Reading Community Schools

ADAPTATION
OR
EXTINCTION!
MR. HOLLANDER’S 8 TH GRADE SCIENCE
CLASS
WHAT IS ADAPTATION?
•
Adaptation is a characteristic usually caused by
a gene mutation that helps an organism survive
and reproduce in its environment
•
Adaptations can be physical and are known as
an adaptive trait
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Ex. 1: Bats have adapted hearing to hunt at night via
sonic response
Ex. 2: Cacti have roots that spread laterally for quite a
ways and activate growth only when wet
Adaptations can occur in behavior too
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Ex. 1: Birds migrate during change in climate for breeding
Ex. 2: Bears hibernate in the winter in order to save
energy during the months without food
•
Adaptations occur over a very long period of
time (1000’s of years) and can be tracked using
the fossil record of a species
•
If an organism is healthier…it can live longer…it
can breed more…and pass down it’s genetic
traits to offspring
•
Adaptations are often very specialized to
specific environments and climates
•
Selective breeding is the human practice of
breeding plants and animals for certain
desirable traits and adaptations
IT’S SURVIVAL OF THE
FITTEST…NATURAL
SELECTION
• Natural selection is the process
by which individuals that are
better adapted to their
environment survive and
reproduce more successfully than
less well adapted individuals
• It was first thought of by Charles
Darwin in 1859
• It has four parts:
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Overpopulation – Lots of Offspring
Inherited Variation – Individual
Combination of Genes/Traits
Struggle to Survive – Only Strong Live
Successful Reproduction – Reproduce
INHERITED VERSUS
LEARNED BEHAVIORS
•
Inherited behaviors are behaviors in which an
organism is inclined towards a particular
behavior; like an instinct
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Ex. 1: A sea turtle newly hatched will automatically move
toward the ocean
Ex. 2 : A male stickleback fish will show aggression
towards anything red during mating season
Learned behaviors are behaviors that are
observed by an individual and that they find it to
be beneficial to them in some way
•
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Ex. 1: A child will not touch a hot stove a second time
because they have been burned once
Ex. 2: A dog rolling over in order to receive a treat
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Inherited behaviors are considered to be
adaptations while learned behaviors are not
•
An inherited behavior is an adaptation because it
is a trait that is passed down genetically to
offspring in order to help it survive in its
environment, however, a learned behavior is one
that you decide to learn and can be either
beneficial or harmful
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Ex.: The ability to learn is an inherited behavior but
learning to not eat poisonous mushrooms is not
Successful organisms often combine both
behaviors together in order to benefit them and
ensure their survival
CHANGE DRIVES CHANGE!!!
•
The Earth is estimated to be 4.6 billion years
old and it has gone through a great deal of
change over time
•
As the Earth’s environments have changed,
the living organisms on the planet have
adapted or died out
•
Species that cannot adapt to change or can
no longer compete with new organisms will
completely die out and become extinct
•
When scientists observe this change over
time in the fossil record it is easy to
recognize new species that have found
success due to their ability to adapt and
change
•
The process in which inherited
characteristics within a population change
over generations such that a new species is
able to arise is known as evolution
•
In a nut shell…organisms either adapt and
evolve to change or the go extinct
USING THE FOSSIL RECORD TO
SHOW ADAPTATIONS OVER TIME
• The fossil record is a timeline
showing a sequence of life indicated
by fossils found in layers of the
Earth’s crust
• A fossil record organizes fossil by
their estimated ages and physical
similarities
• The fossils found in the newest
layers of the Earth’s crust tend to be
closely related to present-day
organisms while fossils from older
layers are less similar and may not
exist any longer
• Scientist believe that all living
species descended from common
ancestors and evidence can be found
in the shared physical traits and DNA
• The fossil record is not perfect and
the holes found between organisms
are called missing links
SUMMING IT ALL UP!!!
• An adaptation is a physical or behavioral characteristic
usually caused by a gene mutation that helps an organism
survive and reproduce in its environment and occur over a
very long period of time
• Natural selection is nature’s way of deciding what
adaptations are best suited for specific environments and
determines the survival of the fittest
• Inherited behaviors are instinctual adaptations and
learned behaviors are observed in their environment
• Environmental change drives changes in species; species
either evolve and adapt or die off and turn extinct
• The fossil record is used to piece together a sequence of
life by using fossils found in the Earth’s crust
THE END!!!