Transcript Species Variation

Species Variation
Obj.6 Describe evidence of species
variation due to climate, changing
landforms, interspecies interaction,
and genetic mutation.
Vocabulary terms:
• Adaptation, Speciation,
Mutation, Extinction, Genetic
Resistance, Isolation,
• Over time, animals may
change behavior or physical
appearance in response to
changes in the environment.
This is called adaptation.
• Adaptation- a
characteristic that
improves an individual’s
ability to survive and
reproduce in a particular
environment.
• Adaptations may be physical,
such as a long neck or striped
fur. Adaptations may be
behaviors that help an
organism find food, protect
itself, or reproduce.
• Scientists think that Earth
has changed over time.
Scientists estimate that
Earth is 4.6 billion years
old.
• Scientists think that as
populations have changed
over time, new species
form. Newer species
descend from older
species.
•
It was proposed that evolution, happens
to population gradually over long
periods of time. The scientist gathered
this information through fossil records
and common ancestry.
Darwin proposed his theory of evolution in
1859 based on his observation in the
Galapagos island.
• Evolution- process in
which populations
gradually change over
time.
• Evidence that organisms evolve can
be found by comparing living
organisms to each other and to the
fossil record.
• The process of evolution is indicated
by fossil records and common
ancestry.
• It was proposed that
evolution happens
through a process called
natural selection.
• Natural selection- the process by
which individuals that are better
adapted to their environment,
survive and reproduce more
successfully than less well
adapted individuals do of the
same species;
• The four parts of natural
selection are:
• 1. Overpopulation ( some eggs survival
–other do not)
• 2. Inherited Variation (Every individual
has its own combination of traits)
• 3. Struggle to Survive (some die
because of predators, starvation,
and disease)
• 4. Successful Reproduction
(those best adapted to the
environment have many offspring
that survive)
New Species
•
A new species can form when a group of
individuals remains isolated from the rest of
its species long enough to evolve different
traits. This isolation can be due to climate,
changing landforms, interspecies
interaction, or genetic mutations and bring
about speciation.
•
The Grand Canyon squirrel populations
represent an example of species variation due
to changing landforms. As the Colorado River
cut through the landscape, it caused the squirrel
population to become separated into two
groups. The two groups, although similar in
appearance, cannot reproduce with each other
because they have developed into two separate
species.
•
•
Pictured to the left Kaibab squirrel
Pictured to the right Albert Squirrel
• Speciation- formation of
new species as a result
of evolution.
• The three steps of speciation are:
1. Separation (part of a population
becomes separated from the rest)
2. Adaptation (the separated group may
evolve different sets of traits )
3. Division (two separated groups may
become very different; groups may not
be able to interbreed anymore)
Extinction
•
This is natures way of getting rid of
weaker species. Only the fittest of the
species will survive.
• Extinction-describes
a species that has
died out completely.
DNA resistance
•
Organisms with shorter life spans can
adapt changing conditions more
rapidly through mutations. These
mutations lead to genetic resistance to
substances such as insecticides and
antibiotics.
• Genetic Resistance- It occurs
when alterations to the DNA
makes the species stronger
and allows them to survive in
any environment that they
may encounter.
•
•
•
Isolated populations can be unable to interact
with each other because of geographic
boundaries like an ocean or mountain. They
can develop unique characteristics and cannot
breed.
Two populations can be isolated if they feed at
different times or reproduce at different times
of the year.
Two or more populations may evolve
differently from each other.
• Isolation stops populations
from interbreeding so new
species evolve.
• Isolation- refers to
species being
separated.
Survival of the fittest
• Organisms that have adapted to
their changing surroundings
pass on the traits that protect
their offspring.
Interaction between
organisms
• There are four ways that species
and individuals affect each other:
competition, symbiotic, predator
and prey.
• Let’s look at each one.
Competition
• When two or more individuals
or populations try to use the
same resource, such as food,
water shelter, space or sunlight.
Prey
• An organism that is
killed and eaten by
another organism.
Predator
• An organism that
eats all or part of
another organism.
Symbiosis
• A relationship in which two
different organisms live in
close association with each
other.
Mutualism
• A relationship between two
species in which both
species benefit.
Commensalisms
• A relationship between two
organisms in which one
organisms benefits and the
other is unaffected.
Parasitism
• A relationship between
two species in which one
species benefits and the
other is harmed.
Parasite
An organisms that feeds off
another organism and the
host is harmed
Host
• The organism in
which the parasite
lives and receives
its food from.