Direct evidence of evolution Evolution is a key unifying principle in biology. As Theodosius Dobzhansky once said, “Nothing in biology makes sense except in the light of evolution.” Evolution is the change in the heritable characteristics of biological populations over successive generations. Charles Darwin on his journey around the earth has found evidence of gradual changes(evolution).We can categorize the evidence into 4 main categories. They are- 1. Biochemical 2. Fossil record 3. Comparative Anatomy 4. Observable events We can divide these 4 categories into 2 sections. They are 1. Direct evidence 2. Indirect evidence

1. Raziya Nasrin
Course Name: Fundamentals of Biological
Science
DIRECT EVIDENCE OF
EVOLUTION

2. EVOLUTION
Evolution is a key unifying principle in biology. As Theodosius Dobzhansky
once said, “Nothing in biology makes sense except in the light of evolution.”
Evolution is the change in the heritable characteristics of
biological populations over successive generations.
Charles Darwin on his journey around the earth
has found evidence of gradual changes(evolution).
He found many types of evidence.

3. EVIDENCE OF EVOLUTION
We can categorize the evidence into 4 main categories.
They are-
1. Biochemical
2. Fossil record
3. Comparative Anatomy
4. Observable events

4. We can divide these 4 categories into 2 sections. They are
1. Direct evidence
2. Indirect evidence.
Direct evidence
1. Fossil Record
2. Biochemical
Evidence of evolution
Indirect evidence
1. Comparative
anatomy
2. Observable
events

5. Direct evidence
The visible evidence which takes us back in time and shows
organisms have changed.
Example: Fossil record , Biochemical evidence.

6. What is fossil?
Fossils are the remains or traces of ancient life that have been
preserved by natural processes. Examples of fossil include shells,
bones, stone imprints of animals or microbes, exoskeletons, objects
preserved in amber, petrified wood, coal, hair, oil, and DNA
remnants.
The fossil record provides incomplete information
about the history of life. Over 99% of all
species that have lived on Earth have
become extinct.

7. How fossils form?
Dead organisms are buried by layers of sediment, which forms new
rock. Most fossils are formed in sedimentary rock. The preserved
remains may be later discovered and studied. The fossil record
provides evidence about the history of life on Earth.

8. This is a picture of plant fossils
was found in coal from the
Minto area. It is 300 million
years old (older than dinosaurs)
The oldest reliably classified
fossils belonging to the genus
Homo date back to a little over
2 million years ago.

9. Fossil Dating
Relative dating allows
paleontologists to estimate a
fossil's age compared with that of
other fossils. In relative dating, the
age of a fossil is determined by
comparing its placement with that
of fossils in other layers of rock .
Rock layers form in order by age
the oldest on the bottom, with more
recent layers on top.
Stromatolites are the
oldest known fossils,
representing the
beginning of life on Earth.

10. Carbon Dating
Radiocarbon dating (also
referred to as carbon dating
or carbon-14 dating) is a
method for determining the
age of an object containing
organic material by using
the properties of
radiocarbon, a radioactive
isotope of carbon. The
method was developed in
the late 1940s at the
University Of
Chicago by
Willard Libby.

11. What is Biochemical Evidence?
Biochemical evidence of evolution is based on the fact that certain
enzymes and chemical processes are found in the cells of all or
nearly all life on Earth. Comparing DNA is the best evidence for
evolution. Similar DNA sequences are the strongest evidence for
evolution from a common ancestor. Biochemistry provides evidence
of evolution in terms of modifications in various biological
molecules, such as enzymes.

12. Although the biochemistry of organisms was not well known in
Darwin’s time, modern biochemistry indicates there is a
biochemical similarity in all living things. This comparison of
biochemical processes with ancient species is called comparative
biochemistry. For example, the same mechanisms for trapping and
transforming energy and for building proteins from amino acids
are nearly identical in almost all living systems. DNA and RNA are
the mechanisms for inheritance and gene activity in all living
organisms. The structure of the genetic code is almost identical in
all living things. This uniformity in biochemical organization
underlies the diversity of living things and points to evolutionary
relationships

13. • The Genetic code
• Triplets of DNA nitrogen base sequences that code for specific
amino acids.
• The amino acid triplet is the same in almost all organisms.

14. Darwin’s explanation of evolution is called Natural
Selection.
Organisms don’t change to survive, they survive (or die!)
because they change!

15. References
1. https://slideplayer.com/slide/267202/
2. https://www.cliffsnotes.com/study-guides/biology/biology/principles-of-evolution/evidence-for-evolution
3. Anon, Available at:
https://www.google.com/search?q=biochemical+direct+evidence&hl=en&sxsrf=AOaemvJqLgAilOOQz1PI-
o6rvvaZMPaUTg:1640937543606&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjcjIrbyI31AhUySWwGHWx
RDGcQ_AUoAXoECAEQAw&biw=1366&bih=625&dpr=1#imgrc=nn30MwZZyWakcM&imgdii=deOkhyP_2YIq
GM.
4. Anon, Available at:
https://www.google.com/search?q=paleontology+direct+evidence&source=lmns&bih=625&biw=1366&hl
=en&sa=X&ved=2ahUKEwiv7b36po31AhXBNLcAHeRbCDMQ_AUoAHoECAEQAA.
5. https://en.wikipedia.org/wiki/Evolution