This document discusses the history and theories of evolution. It introduces Lamarck's theory that acquired traits can be inherited, followed by Darwin's theory of evolution by natural selection. Darwin observed variation between species on the Galapagos Islands and concluded they descended from a common ancestor. His theory of natural selection proposed that individuals with inheritable traits better suited to the environment would survive and pass on those traits, leading to changes in species over generations. The document also discusses influences on Darwin's thinking like Malthus, Hutton, Lyell, and selective breeding observed by farmers.

2. GROUP MEMBERS
IHTISHAM
&&
ali khan

3. INTODUCTION
HISTORY OF EVOLUTION
DIFFERENT THEORIES OF EVOLUTION
APPLICATION
CONCLUSION

4.  Evolution is the change in the inherited
characteristics of biological populations over
successive generations. Evolutionary processes
give rise to diversity at every level of biological
organisation, including species, individual
organisms and molecules such
as DNA and proteins.[1]

5. ● First scientist to propose
a mechanism for how
organisms change (1809)
● His idea: “Inheritance of
Acquired Traits”
● Greater use of a body part
would change it, and the
change would pass on to
the organism’s offspring.

7. 1. Organisms have a
desire to change.
They have an
inborn urge to
better themselves
for their
environment.
Ex: Birds tried to fly and
eventually grew wings
because of their efforts.

8. 2. Organisms can change
shape by using or not
using their bodies.
Ex: The wings of a bird that
does not fly would get
smaller from generation to
generation and the wings
would eventually
disappear.

9. 3. Organisms can pass
on acquired traits to
their offspring.
Ex: If an animal developed
muscles from lifting
weights during its
lifetime, it could pass
those muscles on to its
offspring.

10. ● English naturalist
● Traveled around the world on the
Beagle (1831); famously stopped
in the Galapagos Islands
● Observed many species and
fossils
● Particularly studied finches,
tortoises, blue-footed boobies

12. ● Darwin noticed that
finches were different
on each Galapagos
Island.
● He concluded that the
different finches had
descended from a
common ancestor and
had changed to be able
to do and eat different
things.

13. 1. Individuals differ, and some of
this variation can be inherited.
2. Organisms produce more
offspring than can survive; thus
they have to compete for
resources, and only the most fit
will survive and reproduce.
3. The most fit organisms pass on
their heritable traits to their
offspring.
4. Species alive today are
descended with modification
(change) from their ancestors.

14. “Descent with modification” means…
…change in organisms over time (many generations)
“Natural Selection” means…
… “pressure” the environment puts on the specific traits
that affects their ability to survive
Hey! I thought this unit was about
evolution??
“Evolution” means…
… change over time
Therefore we now call Darwin’s idea “biological
evolution.”

15. Lamarck’s explanation for
the giraffe’s long neck:

16.  Thomas Malthus – Populations
 James Hutton and Charles Lyell –
Geological Record
 Farmers – Breeding

17. His prediction:
 the human population
would grow faster than
the space and food
supplies needed to
sustain it.
 The only checks on the
human population
would be war, famine,
and disease.

18. Malthus’ theory of population growth was
observed by Darwin in other animal
populations as well.
In nature, Darwin saw many organisms that
produced many offspring. Most died.
Darwin wondered, what determines which
individuals survive and reproduce?

19.  Hutton is considered the
“father of modern
geology”
 Based on layers found in
rock structures, Lyell
proposed that Earth is
millions of years old
 Lyell proposed that
geological features could
be built up or torn down
over long periods of time
Grand Canyon, Arizona

20.  After reading Lyell’s book, Darwin was
convinced that Earth was old.
 Darwin reasoned that if geological phenomena
could change the earth, then life on Earth
could change as well.

21.  Farmers recognize
that within a
population, there is
natural variation.
 Farmers improve
their plants and
animals through
selective breeding.

22. Farmers bred the plants or animals with the most
desired traits.
This process of humans allowing only the best
organisms to reproduce is called artificial
selection.