Hook Video: Battle of Kruger

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Hook Video Battle of Kruger
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Introducing Evolution

• Evolution The relative change of the gene pool
  (alleles) of a population that occurs over
  generations.

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Variation Within Species

• Variations structural, functional, or
  physiological differences between individuals
  within a species.
• Variations are created by the different
  combinations of genetic information (alleles)
  that offspring inherit from their parents.

The kittens in this litter have different fur
colour and patterns, partly because each kitten
inherited a different combination of alleles from
its parents.
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What is the ultimate source of genetic
variation?
Mutation a permanent change in the genetic
sequence (DNA) of an organism and the only source
of new genetic variation (new alleles). This is
only true if the mutation alters the DNA in a
gamete, so that DNA can be passed on to
offspring.Mutations can occur spontaneously
during DNA replication (S-phase), or caused by
mutagens (eg. UV-radiation)

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Variations Adaptations

• Adaptations structural, behavioural, or
  physiological processes that help an organism
  survive and reproduce in a particular
  environment.

Camouflage allows this stick insect
(Eurycnema goliath) to blend in with
its environment and avoid being eaten
by predators.
Many owls such as this barn owl (Tyto alba)
can sneak up on their prey because
of another adaptation fluffy feathers make their
flight quite silent.
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Types of Adaptations

• ? Mating Rituals Dancing and/or Singing
  Behavioural adaptation

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• ? Hibernation Physiological adaptation

Hibernation allows ground squirrels to survive in
climates with harsh winters. They reduce their
metabolism in order to conserve energy.
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• ? Mimicry Structural adaptation

• Mimicry - an adaptation in which harmless
  species physically resemble a harmful species.
  Predators avoid the harmless species as much as
  they do the harmful one.

The viceroy butterfly (top) has coloration
similar to the bad-tasting species monarch
butterfly (bottom).
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• Hornet Moth
• looks like a hornet, but is
• completely harmless.

Io Moth (Automeris io) spread their wings to
reveal a startling eyespot pattern, used to
deter predators.
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• Infer.......
• How could the camouflage of individual stick
  insects help the survival of a population of
  stick insects?

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• Organisms constantly face environmental
  challenges that limit their ability to survive.
• Severe weather, famine, and competition for food,
  space and mates are all challenges to survival.
• Environmental conditions determine whether a
  variation in an individual has a positive,
  negative, and/or neutral effect.

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• Individuals with a helpful variation are more
  likely to survive and have a higher chance of
  passing on the genetic information (alleles)
• A characteristic may not give an individual a
  particular advantage now but may become critical
  for survival later as the environment changes.

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Selective Advantage a genetic advantage that
favours an organisms chance of survival and
reproduction, usually in a changing
environment. Eg. Antibiotic-Resistant
Bacteria E.g. When a human was born with a
thumb E.g. Drought resistant frutis