EVIDENCE OF EVOLUTION
INVESTIGATORY PROJECT REPORT
Submitted by
CHRIS JOHNSON
12-AB
in partial fulfillment for the biology
practicals of
AISSCE PRACTICALS 2022’23
DEPARTMENT OF BIOLOGY
VELAMMAL VIDHYASHRAM
SURAPET CHENNAI - 600 066
VELAMMAL VIDHYASHRAM
SURAPET CHENNAI- 600 066
BONAFIDE CERTIFICATE
Certified that this investigatory project report titled, EVIDENCE OF
EVOLUTION is the bonafide work of CHRIS JOHNSON of Grade 12 in the academic
year 2022’23, who carried out the project under the guidance of Ms. ARANDHA K M
Place : Chennai
Date :
TEACHER IN-CHARGE
INTERNAL EXAMINER EXTERNAL EXAMINER
ACKNOWLEDGMENT
I am extremely grateful to my mentor Ms. Arandha K.M , Department of
Biology, Velammal Vidhyashram Surapet, Chennai, for her valuable guidance and kind
help during the course of my project.
I wish to express my gratitude to Mrs. CHITRA MADHAVAN Principal,
Bharathi Wing, Velammal Vidhyashram Surapet, Chennai for her continuous support for the
successful completion of this project work.
I express my deep gratitude to my parents, friends and my family members for
their great support and patience.
Chris Johnson
TABLE OF CONTENTS
Sl No TITLE PAGE
NO.
Evidence Of Evolution
Introduction:
The birth of modern evolutionary theory can be traced to the mid-nineteenth century, and the
publication of Charles Darwin's book, The Origin of Species by Means of Natural Selection in 1859.
The evidence of evolution is one of the fundamental keystones of modern biological theory. It
is the only way which can prove all the proposed theories of evolution. We have number of evidences
to prove the biological evolution namely fossils, comparative anatomy, embryo development
pattern, direct observation.
Evolution is the unifying concept that runs through all the life sciences, from the origin and
diversification of life to understanding human behavior to dealing with the challenges posed by
disease.
Aim:
To study about the Evidence Of Evolution
The theory of evolution explains how populations change over time and how life
diversifies the origin of species. It does not shed light on the beginnings of life including
the origins of the first cells, which is how life is defined. And we have the evidences to
prove it.
Objective:
To study about the different types of evidence of evolution
To know about the sources of evidence
To understand the different methods for the study of evolution
The evidence for evolution has primarily come from four sources:
1. the fossil record of change in earlier species
2. the chemical and anatomical similarities of related life forms
3. the geographic distribution of related species
4. the recorded genetic changes in living organisms over many generations
Methodology:
Surveys
Scientific studies
Theoretical material
Books
Paleontology;
The study of fossils is known as paleontology. Fossils are the preserved remains or traces of
animals, plants, and other organisms from the past. Fossils are important evidence for evolution
because they show that life on earth was once different from life found on earth today
Fossil record- Fossils are the preserved remains of previously living organisms or their traces, dating
from the distant past. The fossil record is not, alas, complete or unbroken: most organisms never
fossilize, and even the organisms that do fossilize are rarely found by humans. Nonetheless, the fossils
that humans have collected offer unique insights into evolution over long timescales.
How can the
age of fossils be determined? First, fossils are often contained in rocks that build up in layers called
strata. The strata provide a sort of timeline, with layers near the
top being newer and layers near the bottom being older. Fossils found indifferent strata at the same site
can be ordered by their positions, and "reference" strata with unique features can be used to compare
the ages of fossils across locations. In addition, scientists can roughly date fossils using radiometric
dating, a process that
measures the radioactive decay
of certain elements. Fossils
document the existence of
now-extinct species, showing
that different organisms have
lived on Earth during different
periods of the planet's history.
They can also help scientists
control the mosquito
populations (and reduce
malaria) in these regions.
(Fig 1)
Morphological and comparative anatomical evidences;
Shown aside are images of the
skeletal structure of the front limbs
of 6 animals: human, crocodile,
whale, cat, bird, and bat. Each
animal has a similar set of bones.
Color code each of the bones
according to this key:
(Fig 2)
Homologous features-
If two or more species share a unique physical feature, such as a complex bone structure or a body
plan, they may all have inherited this feature from a common ancestor. Physical features shared due to
evolutionary history (a common ancestor) are said to be homologous.
For instance, all vertebrate embryos (including humans) have gill slits and a tail during early
development. The developmental patterns of these species become more different later on (which is
why your embryonic tail is now your tailbone, and your gill slits have turned into your jaw and inner
ear)
(Fig 3)
Convergent evolution:
Convergent evolution refers to the evolution in different lineages of structures that are similar or
‘analogous’, but that cannot be attributed to the existence of a common ancestor; in other words, the
fact that the structures are analogous does not reflect homology. A similarity may reside at the
phenotypic level, in which case the lineages share the
overt trait, but the underlying DNA sequence are
different. Convergent evolution occurs when species
occupy similar ecological niches and adapt in similar
ways in response to similar selective pressures. Traits
that arise through convergent evolution are referred to
as ‘analogous structures’. They are contrasted with
‘homologous structures’, which have a common
origin. The opposite of convergent evolution is
‘divergent evolution’, whereby related species evolve
different traits, this gives us one of the evidences of
evolution
( Fig 4)
Here in this picture we can clearly see the convergent evolution of these creatures that take flight and
have developed similar wing structures despite being in different conditions.
Adaptive radiation:
Evolution of an animal or plant group into a wide variety of types adapted to specialized modes
of life. Adaptive radiations are best exemplified in closely related groups that have evolved in a
relatively short time. A striking example is the radiation, beginning in the Paleogene Period (beginning
66 million years ago), of basal mammalian stock into forms adapted to running, leaping, climbing,
swimming, and flying. Other examples include Australian marsupials, cichlid fish, and Darwin’s
finches (also known as Galapagos finches).
Many examples of speciation by adaptive radiation are found in archipelagos removed from the
mainland. In addition to the Galapagos Islands, the Hawaiian archipelago, with its several volcanic
island actively small total land area, hosts an astounding number of plant and animal species that are
endemic; that is, they have evolved there and are found nowhere else. More than 90 percent of the
native species of Hawaiian flowering plants, land mollusks, birds, and insects are endemic.
Darwin's finches:
Charles Robert Darwin known for his contribution in evolution theory studied the plant and
animals of Galapagos island. He observed that on Galapagos island there were small blackbirds which
differed mainly in the feeding habits and shape of beaks. The name Darwin finches used by David
Lank in his popular book Darwin’s Finches. Due to the popularity of this book the Galapagos finches
also known as Darwin Finches. The term Darwin's finches were given to Galapagos finches by Lank.
In Galapagos island due to a variety of food eating habits the beak of Galapagos finches evolved
differently and hence in Galapagos island Darwin
observed different species of finches which differed
mainly in the shape of beaks. The different food eating
habits developed a due variety of food on Galapagos
island, so the original seed-eating ancestor birds
evolved into different food eating birds.
Now they are:
Geospiza magnirostris.
Geospiza parvula.
Certhidea olivacea.
Geospiza fortis. (Fig 5)
Australian Marsupial Mammals:
Australian marsupials are also good examples of adaptive radiation. Marsupials are the
members of mammals having a pouch to carry their young’s ones. Marsupials like Koala, Kangaroo,
Wombat originated from an ancestral marsupial within the same island Australia.
Different varieties of marsupials differ from each other in morphology. Placental mammals also evolve
through adaptive radiation and develop into different varieties.
The different animals are:
Grazing – Kangaroo
Burrowing- Marsupial moles
Arboreal- Koala, tree kangaroo
Teeth like rodents- Wombats, marsupial
rats
Rabbit-like – Hare wallabies
Wolf-like – Tasmanian wolves
Ant eating – Banded anteater
(Fig 6)
Badger-like – Tasmanian Devil
(Fig 6)
Biochemical evidence:
Evolution reflects changes over the coming generations in the heritage features in biological
populations. These are the expressions of the genes which are transmitted during replication from
parent to descendant. There are many features of mutation, genetic recombination and other causes of
genetic variation within a given population.
Evolution takes place as evolutionary mechanisms such as natural and genetic mutation
operate upon this variation, which contribute to certain features being more common or scarce in a
population.
Biochemical similarities indicate proteins and nucleic acids. Many related DNA
sequences species are called close relatives or have originated from the same ancestor.
Hereditary material such as DNA and RNA bears genetic material from generation to generation.
This is recombined during meiosis which induces variation. However, these biochemical
similarities provide numerous evidence of evolution from common ancestors. Biochemicals which are
remarkably similar in shapes and roles in all organisms are one class of biochemical proof of
evolution, homologous molecules.
(Fig7)
Cytochrome c is an example of a homologous protein. This protein is present and plays a
significant function in cellular respiration in nearly all living cells. Metabolism is another example of
biochemistry. The same processes are used in all life forms to trap and refine energy and then to make it
protein and amino acids..
Evolution takes place as evolutionary mechanisms such as natural and genetic mutation operate upon
this variation, which contributes to certain features being more common or scarce in a population.
Metabolism, cytochrome c, DNA, RNA, etc. are those biochemicals that are significant among diverse
organisms in evolution.
Evidence of breeding:
Man has domesticated many wild animals. Humans have created hundreds of breeds of selected
plants and animals.
Now-a-days the intensive breeding program has developed different breeds belonging to the same
group. The best example of such organisms would be, dogs.
(Fig 8)
we can see, through the DNA evidence, all these different breeds of dogs were produced through
wolves from recent molecular evidence shows that dogs are descended from the gray wolf,
domesticated about 130,000 years ago.
Nature took millions of slow paced evolutions for what humans did in a few hundred years.
Ancestry:
Line of descent : LINEAGE
Darwin thought of evolution as "descent with modification," a process in which species
change and give rise to new species over many generations. He proposed that the evolutionary history
of life forms a branching tree with many levels, in which all species can be traced back to an ancient
common ancestor.
(Fig 9)
In this tree model, more closely related groups of species have more recent common
ancestors, and each group will tend to share features that were present in its last common ancestor.
We can use this idea to "work backwards" and figure out how organisms are related based on their
shared features.
Biogeography:
The geographic distribution of organisms on Earth follows patterns that are best explained by
evolution, in combination with the movement of tectonic plates over geological time. For example,
broad groupings of organisms that had already evolved before the breakup of the supercontinent
Pangaea (about 200 million years ago) tend to be distributed worldwide. In contrast, broad groupings
that evolved after the breakup tend to appear uniquely in smaller regions of Earth. For instance, there
are unique groups of plants and animals on northern and southern continents that can be traced to the
split of Pangaea into two supercontinents (Laurasia in the north, Gondwana in the south).
The evolution of unique species on islands is another example of how evolution and geography
intersect. For instance, most of the mammal species in Australia are marsupials (carry young in a
pouch), while most mammal species elsewhere in the world are placental (nourish young through a
placenta). Australia’s marsupial species are very diverse and fill a wide range of ecological roles.
Because Australia was isolated by water for millions of years, these species were able to evolve without
competition from (or exchange with) mammal species elsewhere in the world.
(Fig 10)
The marsupials of Australia, Darwin's finches in the Galapagos, and many species on the Hawaiian
Islands are unique to their island settings, but have distant relationships to ancestral species on
mainlands. This combination of features reflects the processes by which island species evolve. They
often arise from mainland ancestors – for example, when a landmass breaks off or a few individuals are
blown off course during a storm – and diverge (become increasingly different) as they adapt in isolation
to the island environment.
Human evidence of evolution:
(Fig 11)
As seen above we can view our (human) evolution tree, of how we had started from Ardipithecus
group, till now the homo sapiens.
Each distinct group has been divided and marked on the above tree feel free to go through it
Current evolution:
Given the abundant evidence supporting the theory of biological evolution, it is highly probable
that evolution has occurred and is still occurring today. However, there remains speculation in regards
to the specific evolutionary path of some species lines and the relative importance of the different
natural processes responsible for their evolution.
Much has been added to our understanding of the nature of evolution since the 19th century. It
is now known that there are six different processes that can operate independently or in consort to
bring about evolution. The understanding of these processes has become the basis for an overall
synthetic theory of evolution. This theory encompasses multiple causes, including Charles Darwin's
concept of natural selection, Gregor Mendel's experimental results concerning genetic inheritance, as
well as a number of crucial 20th century discoveries.
Conclusion:
No matter what position a person takes on evolution, it is important to understand why almost
all professional biologists affirm the evolution of all life on Earth. One of the main motivations behind
this paper was my growing perception that what appeared to be an adequate understanding of the
causes for and solutions to the widespread non-acceptance of evolution was not in fact a solid
consensus. Everyone knows that religious beliefs are often associated with resistance to evolution.
Yet when confronted with the practical task of teaching a particular class or designing a
particular museum exhibit, it quickly becomes clear that the actual range of potential causes for non-
acceptance is much larger, that neither religion nor biology is necessarily the right place to start, and
that simply assuming that we know what our audience thinks and why can lead our educational efforts
seriously astray.
Unexpected evidence that I was correct about this lack of consensus came from comments by
two reviewers of this paper, who stridently objected to various of my conclusions with words to the
effect that “everyone knows,” for example, that there is no demonstrated relationship between NOS
and acceptance of evolution; that terminological confusion and factual misunderstanding are at most
only minor contributors to non-acceptance; that there is no disagreement in the science education
community about NOS; that there is no empirical support for the idea that teaching macro evolution
will increase acceptance of evolution; that there is no support for the idea that increased exposure to
evolution can produce decreased acceptance; and that “good teachers” will automatically know how to
deal with any and all obstacles to their students accepting evolution.
Despite these statements, my review (and re-review) of the large and growing
evolution education literature, together with my long experience teaching evolution in a
wide variety of settings, demonstrates that all of these statements are at best
oversimplifications and at worse simply untrue. That these reviews came from very distinguished
individuals in the field of evolution education reinforces my basic conclusion: that the appallingly
widespread rejection of evolution is a much more complicated problem than most scientists, educators,
journalists, and legislators think it is, and that those who care about reversing this situation should do
more to take this complexity into account as we seek to come up with new and more adequate
solutions.
References and Appendix:
https://www.sciencedirect.com/science/article/abs/pii/S0016328722000167
https://biologos.org/common-questions/what-is-the-evidence-for-evolution
https://www.doubtnut.com/question-answer-biology/the-evidence-of-evolution-is-based-
on-648084947
https://www.khanacademy.org/science/biology/her/evolution-and-natural-selection/a/
lines-of-evidence-for-evolution#:~:text=Evidence%20for%20evolution%3A
%20anatomy%2C%20molecular,%2C%20fossils%2C%20%26%20direct
%20observation.
https://en.wikipedia.org/wiki/Evidence_of_common_descent
https://humanorigins.si.edu/
https://www.dentonisd.org/
https://www.uc.edu/content/dam/refresh/cont-ed-62/olli/s21/kahn-evidence-of-
evolution.pdf
https://www2.palomar.edu/anthro/evolve/evolve_3.htm
https://courses.lumenlearning.com/suny-wmopen-biology1/chapter/outcome-evidence-
for-evolution/
https://royalsocietypublishing.org/doi/10.1098/rstb.2016.0020
