Transcript 7.1 adaptation and variation
SBI3U Ms. De Sousa
What does the saying: « Only the fittest survive » mean to you?
Organisms that survive
environmental challenges
are able to pass on their
genetic information to offspring.
By passing on the genetic information, their
species survive.
The varying
interactions between species
and the
envrionmental changes
causes some species to go
extinct
while others thrive.
Adaptations can by structural, behavioural or phsyiological.
Structural Adaptation:
bear.
physical features
of an organism like the beak on a bird or the fur on a Behavioral Adaptation: Things
organisms do
to survive.
Physiological Adaptation: changes or chemical reactions
that occur
within
an organism.
Many organisms are able to camouflage and
blend in with their environment
which enables them to
escape predators
.
Organisms undergo a variety of
adaptations
that enable them to
survive and escape predators.
Adaptation:
environment. a structure, behaviour or physiological process that helps an organism survive and reproduce in a particular
Hibernation is a physiological adaptation. It allows organisms to
survive in harsh conditions
by keeping warm and
preserving their energy
Mimicry is a form of
structural adaptation,
where the animal is able to
imitate something other than what it is.
Butterflies use it as a
protection mechanism
to trick predators into thinking they are an
inedible species
.
The intention of mimicry is to draw attention to yourself. This is usually achieved, through the presence of bright colours.
Clicker questions 1-2
Adaptation is due to
gradual , accumulative changes
that helps an organism survive and reproduce. Adaptations are a result of
genetic mutations
in an organisms’
DNA
. These
mutations must be heritable
order for the
adaptation to persist.
in
As a result of the mutations, there are many
variations that appear in the population
. Although a mutation may lead to variation,
not all variations become an adaptation
. Variations: differences between individuals which may be structural, functional or physiological.
Depending on the environment, certain
variations will persist while others do not
. If the variation enables an organism to survive in an environment, the organism will
pass on the genetic mutation
to their offspring. Those who survive have a
greater chance
of passing on their genetic information.
Although variations may not play a big role at one point in time, as the
environment changes
, that variation may
to an organism’a survival.
become useful
If that organism survives, it is able to
pass on that trait to the offpsring
allowing them in turn to survive in such an environment.
Although organisms are part of the same species, there is alot of variation. Humans have a great deal of variation due to the
random combinations of alleles
that we inherit from our parents. The
different combinations of alleles
contribute to the variation in
phenotypes of many species
.
Mutations :
changes in the genetic material (i.e. DNA) of an organism
The mutation in the
nucleotide sequence
creates new
versions of alleles
. All mutations happen
spontaneously
DNA is copied in the
S phase.
when
CGA-CCA-ACG-GCG...
Amino Acids Produced:
Threonine - Alanine ...
Arginine - Proline CGA-CCA-
GA
A-CGG-CG... Amino Acids Produced: Arginine - Proline -
Glutamic Acid
- Arginine ...
Some mutations can alter the
shape and function of a cell
. The organism has mechanisms that are able to get rid of these malfunctioning cells. If the malfunctioning cell is able to
bypass this checkpoint
, it
proliferates and accumulated into a tumor
.
Clicker question 3
When the environment changes, certain mutations that were once unfavorable can now be favourable.
Selective advantage:
environment. a genetic advantage that improves an organisms’ chance of survival, usualyl in a changing
When an organism has a mutation that has a selective advantage, that orgnaism is favored in terms of survival and reproduction.
Clicker question 4
Bacteria and viruses tend to have a
rapid rate of reproduction.
Due to the rapid reproduction, a
mutation
that has a selective advantage can be
spread into a population quickly
Thus, when there is a change to the environment,
a whole population of bacteria may be able to survive.
This may result in antibiotic resistance.
If a bacteria undergoes a mutation that allows it to survive against bacterial drugs, it becomes resistant to the antibiotic. New populations of bateria will grow and be ressistant to the medication.