Download Changing environments

CHANGING
ENVIRONMENTS
And variation
Changing environments & variation

Some environments can change over a long or short
period of time.
Changing environments & variation
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Some environments can change over a long or short
period of time.
Some organisms have phenotypic variations that
allow them to survive these changes.
Changing environments & variation
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Some environments can change over a long or short
period of time.
Some organisms have phenotypic variations that
allow them to survive these changes.
They will breed and pass on to their offspring the
genotypes that produce these successful variations.
Droughts
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Read the information given and highlight points you
might use in an exam
Flooding

Read the information on flooding and highlight the
points you might use in an exam.
Mutations & Variation
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Mutations create new alleles.
Mutations & Variation
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Mutations create new alleles.
New alleles are the source of variation
Mutations & Variation
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Mutations create new alleles.
New alleles are the source of variation
If the variation or new adaptation enhances the
individual’s survival, it will spread throughout the
population.
Mutations & Variation
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Mutations create new alleles.
New alleles are the source of variation
If the variation or new adaptation enhances the
individual’s survival, it will spread throughout the
population.
**Refer to previous information on mutations**
Mutations that occur in body cells

These only affect new body cells formed from the
mutated cell.
Mutations that occur in body cells


These only affect new body cells formed from the
mutated cell.
The type of cell division involved is mitosis.
Mutations that occur in body cells
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These only affect new body cells formed from the
mutated cell.
The type of cell division involved is mitosis.
The mutation is not passed onto the affected
individual’s offspring.
Mutations that occur in body cells


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These only affect new body cells formed from the
mutated cell.
The type of cell division involved is mitosis.
The mutation is not passed onto the affected
individual’s offspring.
EG – a skin cell gets hit by UV from the sun. A
mutation occurs and the new cell starts to divide
rapidly = skin cancer. This skin cancer is not passed
onto this person’s offspring however.
Mutations that occur in the gametes

Mutations that form in the egg or sperm will be
passed onto the offspring if that egg or sperm is
fertilised.
Mutations that occur in the gametes
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
Mutations that form in the egg or sperm will be
passed onto the offspring if that egg or sperm is
fertilised.
EG – There is a mutation in the gene for producing
melanin (what makes skin colour) during meiosis. This
mutated egg is fertilised and as the zygote divides,
all those cells have a mutation for melanin. When
the individual is born they will have darker skin than
their parents.
Mutations that occur in gametes

Most mutations are harmful to an organism – it’s
estimated that every person has 4 mutations in their
cells and 2 of those could be harmful if expressed
in the phenotype.
Mutations that occur in gametes


Most mutations are harmful to an organism – it’s
estimated that every person has 4 mutations in their
cells and 2 of those could be harmful if expressed
in the phenotype.
Occasionally a mutation results in a trait that can
help the organism survive in changed environmental
conditions.
Mutations that occur in gametes



Most mutations are harmful to an organism – it’s
estimated that every person has 4 mutations in their
cells and 2 of those could be harmful if expressed
in the phenotype.
Occasionally a mutation results in a trait that can
help the organism survive in changed environmental
conditions.
The new trait will be passed onto those offspring
that survive while others without the new trait die.
Mutations that occur in gametes




Most mutations are harmful to an organism – it’s
estimated that every person has 4 mutations in their
cells and 2 of those could be harmful if expressed
in the phenotype.
Occasionally a mutation results in a trait that can
help the organism survive in changed environmental
conditions.
The new trait will be passed onto those offspring
that survive while others without the new trait die.
This new trait then becomes an adaptation.
Read
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Antibiotic-resistant Bacteria info and highlight key
points.
Pesticide resistance and highlight key points.
Complete
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3D now
Or finish for homework.
You should be studying for your test on Friday too
Sexual and asexual reproduction & variation