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SCIENCE 10 QUIZ 5 3rd Quarter
Test I: MULTIPLE CHOICES: Write the letter of the
correct answer.

Test II: Fill in the comparison table below.Write
your answers on a separate paper
7.
9.
8.
10.
11. 12.
Location in the cell
13-16. 17-20.

Over the years, man is always in a quest to
answer questions about his origin and
existence.
Part of this quest is finding the answer to
where did we all come from?
Why do organisms which existed before no
longer exist at present?
What happened over the years that cause some
organisms to be completely extinct today?

These are just a few of the
mind-boggling questions
that need to be answered by
facts and solid evidence
through Science.

Objectives
▪Explain how fossil records,
comparative anatomy, and genetic
information provide evidence for
evolution
▪Explain the occurrence of evolution

Evolution
▪Defined as the change in the
genetics of a population over time

Two types of Evolution
1. Divergent Evolution
▪ Splitting in ancestral population into two or
more sub-populations that are
geographically isolated from one another
2. Convergent Evolution
▪ Is an increase in similarities among species
derived from different ancestors as a result
of similar adaptation to similar environment.

Sources of
Evidence for
Evolution

1. Evidence from fossil Records
▪ Fossils are examples of evidences that
paleontologists use in studying evolution.They
are traces of organisms that lived in the past
and were reserved by natural process or
catastrophic events.They can be remains of
organisms which include bones, shells, teeth
and also feces embedded in rocks, peat, resin,
and ice. Paleontologist is a person who studies
fossils.

▪ Most fossils were commonly found in
sedimentary rocks.They were from the hard
parts of the organism like woody stem, bones,
or teeth.

The age of fossils is determined through fossil
dating. It can be specified as either relative or
absolute dating.
1. Relative dating - method used to determine
the age of the rocks by comparing them
with the rocks in the other layer.The
younger sedimentary rock layer is assumed
to be found on top and the older rock is
found at the bottom layer. Fossils found at
the bottom layer are assumed to be older
than those on the upper layer.

2. Absolute dating -is through the use of
radioactive isotopes such as carbon-14.
Radiometric dating is a method used to
determine the age of rocks using the decay of
radioactive isotopes present in rocks. All
organisms have decaying carbon-14 in it.
Plants and animals that are still alive
constantly replace the supply of carbon in
their body and the amount of carbon -14 in
their body stays the same.

2. Comparative Anatomy
Homologous structure - Structures from different
species which have similar internal
framework, position, and embryonic
development are considered to be
homologous. Homologous structures may
perform different functions in the species
living in the different environment, or it may
have the same origin but different functions.

Here are some example of homologous
structures: forelimbs of dog, bird, lizard,
and whale, which are structurally the same,
but functionally different.

The presence of
homologous structures is a
strong indicator that the
organisms evolved from
common ancestors.This
type of evolution is called
divergent evolution.

2. Comparative Anatomy
Analogous structure - Structures of
unrelated species may evolve to look
alike, because thestructure is adapted
to similar function.These are called
analogous structures.Analogous
structures have similar functions but
different origin.

Examples are wings of birds, bats, and
insects that have the same function but
different in origin.

In convergent evolution, analogous
structures of unrelated organisms from
different ancestors develop similar
function such as butterfly wings and
bird wings.

An embryo is an early stage of development in
organisms. Embryonic development include
stages such as blastula, gastrula, and
organogenesis.The embryo of fishes,
salamanders, lizards, birds, cats, and humans are
similar during the first stage of their embryonic
development; and have several homologous
structures that are not present when the
organisms are adults. Studies show that species
that are closely related exhibit similar embryonic
development. Even when in the adult stage, the
organisms are quite different.

Theories of Evolution
Jean Baptiste de Lamarck
is a French naturalist
born on August 1, 1744
a soldier and a biologist who first proposed the idea
that acquired characters can be inherited
This is known as Lamarckism.
He also believed that organisms change over time to
adapt to changing environments.

1.Theory of Need - states that organisms
change in response to their environment.
Their ability to survive helped them
developcharacteristics necessary for
them to adapt in a given environment.
2.The Theoryof Use and Disuse - which
according to Lamarck,
organs not in use will disappear while
organs in use will develop.

3. Theory of Acquired
Characteristics – states that a
parent animal could pass on to its
offspring the characteristics it
had acquired during its lifetime

Charles Darwin
an English biologist, geologist, and
naturalist is famous for hisTheory of Evolution by Natural
Selection.
Darwin said that giraffe species originally have
varying neck lengths but due to natural selection it favored
those with longer necks that feed on taller trees.
Those with shorter necks vanished from the pool of species due to
lack of food supply as they were not able to reach for the leaves
of taller trees.

1. Theory of Natural Selection
- According to Darwin, giraffe species
originally had varying neck lengths
but natural selection favored the
survival of giraffes with longer necks
that could feed on taller trees that
were available. Giraffes with short
neck were eliminated due to lack of
accessible food supply.

AugustWeismann,
a German evolutionary biologist ranked
as the second most notable evolutionary theorist of the 19th
century, challenged Lamarck’s theory which marks a
turning point to demand more evidence.
He was not convinced and pointed out that if he will cut off the
tails of the mice for consecutive generations would not create a
tailless type.

AugustWeismann,
He was successful in pointing out the
inadequacy of Lamarck’s theory and distinguish somatic
cells from germ cells.
Weismann proposed that changes in
the somatic cells, such as the elongation of giraffe’s neck,
cannot be passed to the germ cells and could not affect the next
generation, a theory later called Weismann Barrier.

What is the importance of studying the
remnants of the past?
Why is there a need to study the evolution of
life?
How does it affect our lives today?

Understanding evolution makes us understand
our world
It explains the diversity of life – the similarities in
the different forms of life, the changes
that occur, and the development of new forms of
life.

Principles of evolution can be applied to improve
crops, livestock, and farming methods.
Natural selection is responsible for the
development of pesticide resistance in
agricultural pests; these pests develop beneficial
traits suited to their current environment and
can easily adapt and survive in the environment.

Studying the evolution of plant’s self-defense
against pests also helps in the development
of effective strategies in sustainable agriculture,
for example, growing crops without chemical
pesticides.

Evolution is not just about fossils,
but it is also about genes,
mutation, populations in living
organisms. Understanding evolution
is important, it helps us solve
problems that impact our lives.

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