ADAPTATION OR EXTINCTION! MR. HOLLANDERS 8 TH GRADE SCIENCE
CLASS
Slide 3
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 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 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 (1000s of years) and can be
tracked using the fossil record of a species If an organism is
healthierit can live longerit can breed moreand pass down its
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
Slide 4
ITS 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: Overpopulation Lots of Offspring
Inherited Variation Individual Combination of Genes/Traits Struggle
to Survive Only Strong Live Successful Reproduction Reproduce
Slide 5
INHERITED VERSUS LEARNED BEHAVIORS Inherited behaviors are
behaviors in which an organism is inclined towards a particular
behavior; like an instinct 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 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 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 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
Slide 6
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 Earths 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 shellorganisms either adapt
and evolve to change or the go extinct
Slide 7
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 Earths crust A fossil record
organizes fossil by their estimated ages and physical similarities
The fossils found in the newest layers of the Earths 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
Slide 8
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 natures 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 Earths crust
