The process by which comparatively better adapted individuals out of a heterogeneous population are favored by the nature over the less adapted individuals is called Natural Selection.
Animals adapting to the environment
Advantaged animals survive and reproduced.
1. Natural Selection
By: Raana Karimpour,
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In God We
Trust
Bachelor, Department of cellular and molecular
biology, Faculty of advanced science and
technology, Tehran Medical Sciences, Islamic
Azad University, Tehran, Iran
Raana Karimpour
3. Decomposers
Decomposers feed on the remains of other
animals. Decomposers play an important role in
the ecosystem.
By digesting dead matter they put nutrients back
into the soil, making them available to
producers.
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Raana Karimpour
4. Herbert Spencer
Survival of the fittest
“The survival of the fittest, which I have here
sought to express in mechanical terms, is that
which Mr. Darwin has called natural selection, or
the preservation off favored races in the struggle
for life”
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Raana Karimpour
6. Charles Darwin
Struggle for Existence
“Members of each species compete regularly to
obtain food, living space, and other necessities of
life”
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7. Fitness
ability of an individual to survive and
reproduce in its specific environment
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Raana Karimpour
8. Result of adaptations
Evolutionary Fitness
organism’s success in passing genes to the next
generation. Where fitness varies, natural selection
can act.
Getting adapted with the Environment
any inherited characteristic that increases an
organism’s chance of survival, Could be
anatomical, behavioral, physiological
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9. Selective pressure
Selective pressures are the factors that cause
young plants and animals in nature to fail to
survive.
- Examples: predators, parasites, drought, lack of
food and temperature extreme.
Some organisms are better equipped to survive,
by having genetic variations that provide
protection.
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Raana Karimpour
10. Definition
The process by which comparatively better
adapted individuals out of a heterogeneous
population are favored by the nature over the
less adapted individuals is called Natural
Selection.
Animals adapting to the environment
Advantaged animals survive and reproduced.
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Raana Karimpour
19. Gene polymorphism
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A gene is said to be polymorphic if more than one
allele occupies that gene's locus within a
population. In addition to having more than one
allele at a specific locus, each allele must also
occur in the population at a rate of at least 1% to
generally be considered polymorphic.
Raana Karimpour
21. Industrial Melanism
Industrial melanism is an evolutionary effect
prominent in several arthropods, where dark
pigmentation has evolved in an environment
affected by industrial pollution, including
sulphur dioxide gas and dark soot deposits.
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27. Different levels of Natural Selection
Naked genes Chromosomes Sexual selection
Intrauterine
Selection
Among
components of
a population
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29. Kin Selection
Kin selection is the evolutionary strategy
that favours the reproductive success of
an organism's relatives, even at a cost to
the organism's own survival and
reproduction. Kin altruism can look like
altruistic behaviour whose evolution is
driven by kin selection.
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