Transcript Evidence for Evolution

Evidence for Evolution
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Fossils
Pentadactyl limb
Embryology
Biochemistry
Classification
Fossils
Remains of organisms found in sedimentary rock
Tissues have been turned into minerals by means of pressure
and temperature
Older fossils are usually found deeper in the sedimentary rocks
(Parts of) Organisms are covered
by sediment, fossilise and are
found
Organisms living in water are
fossilised more often
Fossilised skeleton of a mammoth
Fossilised fronts (leaves) of a fern
Fossilised human foot print
Fossilised dinosaur foot print
Pentadactyl limb design
Competition in the seas and changing climates
may have forced fishlike animals to adapt to living on land
Swim bladders turned into lungs and fins into limbs
Fish
The body plan changed slowly
The end result was a pentadactyl vertebrate, an Amphibian
Amphibians
Amphibians developed into Reptiles
Reptiles into Birds
And Mammals
The pentadactyl limb continued to
develop
The early horse was the size of
a dog. The animal lived in the
Dense tropical forests and needed
The four-toed foot for support on
the soft soils.
When the climate changed forests
disappeared and the “horses”
adapted. They lost toes and the
bones in the remaining finger
became longer.
A hoof protected the tip against
damage.
The horses had to be taller to see
over the tall grass and able to run
faster.
The present-day horse is four times
taller than its ancester.
Embryology
In the 19th century, Haeckel suggested that Embryology also supports
the theory of evolution. Later however, it was discovered that he had
manipulated his findings and diagrams
Haeckel’s hypothesis was that all Vertebrate animals undergo evolutionary
steps when they develop from a fertlised egg cell into a fully developed
foetus. He saw the above investigation as proof of his hypothesis.
Scientists now only support parts of his idea.
Haeckel is also famous for his art work on marine animals.
Below diagrams of Coelenterates, jelly fish and sea anemones
Biochemistry
The use of DNA, aerobic respiration and photosynthesis and many
chemical recations are universal, used by many organisms
Classification shows the relationship between organisms and how
they may have developed out of eachother
Theory of evolution
A young Darwin travelled to
South America and gathered
a large number of species.
After his return to England, he
continued studying these specimen
And he did several experiments
on artificial selection of plants and
Animals
In 1859 Darwin published his theory
of evolution: Survival of the Fittest
In his book:
“On the Origin of Species”
• Darwin stated three rather obvious facts:
• - Species produce more offspring than
needed for the continuation of the species
• - Offspring is not identical (variation)
• - There is not enough food/space for all
individuals produced (survival of the fittest)
Species produce more offspring than needed for the continuation
of the species
Offspring is not identical (variation)
-There is not enough food/space for all individuals produced
-(survival of the fittest)
Evolution based upon selection
of the best variation in the
offspring
Small variations won’t make a
difference. The bigger de
difference however the more
effect on the success of the
individual
Small differences changed the size and shape the beak of the ancester
This happened in response to changes in the environment (availability of
And competition for food).
Some birds remained general feeders others specialised
Speciation
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Mutation
Variation
Selection
Speciation
Evolution
Mutation
Variation (Lamarck)
Variation (Darwin)
Natural Selection
Sexual Selection
Speciation
Evolution