evolutionary theory and evidence evolution notes part 1

Evolutionary Theory and Evolutionary Theory and EvidenceEvidence

Evolution Notes Part 1Evolution Notes Part 1

Evolutionary TheoryEvolutionary Theory

• What is What is evolution?evolution?

• Change over timeChange over time• The process by which The process by which

modern organisms have modern organisms have descended from ancient descended from ancient organismsorganisms

The theory of Evolution

• Evolution is known as the gradual change in the characteristics of a species over time.

• A species is a group of organisms whose members look alike and successfully reproduce among themselves.

Early Ideas on Earth’s Animals

• Aristotle believed that species were fixed creations arranged by their complexity

• This idea lasted 2000 years

Contributor’s to Darwin’s Contributor’s to Darwin’s thinking include:thinking include:

Hutton – theory of geological change (gradualism)

changes in earth due to slow continuous processes

Thomas Malthus- struggle for existence (resources)

Jean-Baptiste Lamarck – Stated that changes are adaptation to environment acquired in an organism’s lifetime

Also stated that changes were passed to offspring (Inheritance of Acquired Traits)

Law of use and disuse – organisms could change size or shape of organs by using them or not using them.

- if a body part were used; it got stronger

- if a body part was not used it deteriorated

Contributor’s to Darwin’s Contributor’s to Darwin’s thinking include:thinking include:

Jean-Baptiste Lamarck- Tendency toward perfection- organisms are

continually changing and acquiring features that help them live more successfully in their habitat

Ex: Bird ancestors wanted to fly, so they tried until wings developed.

Charley Lyell- uniformitarianismgeologic processes still changing earth

Georges Cuvier- Species extinction (catastrophism) evidence Fossils

species disappear due to a catastrophic event to earth’s crust

Charles DarwinCharles Darwin

• Who was Who was Charles Charles Darwin?Darwin?

• What did What did he study?he study?

• British naturalist who British naturalist who traveled around the world traveled around the world on the on the H.M.S. BeagleH.M.S. Beagle

• Observed living things, Observed living things, making observations and making observations and collecting evidence that led collecting evidence that led to his proposed hypothesis to his proposed hypothesis about how life changes about how life changes over timeover time

Charles DarwinCharles Darwin

• What was the What was the name of the book name of the book he wrote and what he wrote and what was it about?was it about?

• On the Origin of On the Origin of SpeciesSpecies established established evolution by evolution by common descent common descent as the dominant as the dominant scientific scientific explanation of explanation of diversification in diversification in nature. nature.

Darwin’s TheoryDarwin’s Theory

• What are What are the main the main points of points of Darwin’s Darwin’s theory?theory?

1.1. Organisms vary from each other Organisms vary from each other and the variety is inheritedand the variety is inherited

2.2. Organisms produce more offspring Organisms produce more offspring than can survivethan can survive

3.3. Since more organisms are Since more organisms are produced than can survive, they produced than can survive, they compete for limited resourcescompete for limited resources

4.4. Each organism has different Each organism has different advantages and disadvantages in advantages and disadvantages in the struggle for existencethe struggle for existence

5.5. Species alive today are descended Species alive today are descended with modification from ancestral with modification from ancestral speciesspecies

Evidence for EvolutionEvidence for Evolution

• What What evidences evidences are there are there for for evolution?evolution?

1.1. Fossils – remains or traces Fossils – remains or traces of organisms, some of of organisms, some of which no longer exist.which no longer exist.

Evidence for Evolution

a. Fossils also provide evidence for evolution. Fossils are the remains of once-living things that are preserved in Earth’s rocks.


b. Fossils have found that many simpler life forms exist early in Earth’s history.

c. The oldest fossils found are bacteria that lived 3.8 billion years ago.

2. 2. Comparative biochemistry Comparative biochemistry – DNA and proteins that – DNA and proteins that show similar structures are show similar structures are also evidence of common also evidence of common ancestryancestry

Evidence for Evolution Evidence for Evolution MolecularMolecular



a. All living things contain similar DNA, RNA, and proteins.

b. By comparing DNA sequences of two organisms, scientists can determine whether or not the organisms are closely related.

c. The relationship can then be used to construct evolutionary pathways.

How many amino acid sequence differences between humans and:

•Horse?

•Tuna?

•Monkey?

• 1. Why can it be said that proteins behave like molecular clocks?

• 2. What would account for the one or two differences among two species DNA?

• 3. If the amino acid sequence is similar, will the DNA sequence also be similar

Evidence for EvolutionEvidence for Evolution

• Other kinds of evidence that support Other kinds of evidence that support organic evolution are adaptations.organic evolution are adaptations.– AnatomicalAnatomical– PhysiologicalPhysiological– BehavioralBehavioral

3. 3. Homologous structures – body Homologous structures – body parts that have different mature parts that have different mature forms but develop from the forms but develop from the same embryonic tissues – same embryonic tissues – evidence of descent from a evidence of descent from a common ancestorcommon ancestor

Evidence for Evolution Evidence for Evolution AnatomicalAnatomical


What do you notice

about these structures?

Evidence for Evolution AnatomicalAnatomical

A. Homologous structures have different function but the SAME structures. These similarities indicates that the organisms probably had a common (the SAME) evolutionary origin.

AND … what do you notice

about these structures?

Evidence for Evolution AnatomicalAnatomical

B. AnaB. Analogous structures have body parts that are similar in function but different in structure. These indicate that the organisms had different yet related ancestors.

44. Similarities in embryology . Similarities in embryology – –

early stages of embryonic early stages of embryonic development show development show similarities that suggest similarities that suggest common ancestrycommon ancestry



Embryology

a. The study of the development of embryos is the field of embryology.

b. Studies of certain embryos indicate evolution from a common ancestor.

5. 5. Vestigial structuresVestigial structures – – traces of homologous traces of homologous organs that are very small organs that are very small and no longer used by the and no longer used by the modern organismmodern organism



Functionless Structures ??

• Some body structures, such as the human appendix and the eyes of cave fish, have reduced forms. We call these vestigial structures.

• These structures support the theory of evolution because they show structural changes over time.

Evidence for Evolution Evidence for Evolution Anatomical Anatomical

6. Some adaptations involve 6. Some adaptations involve changes in the structure of body changes in the structure of body parts: mimicry and camouflage. parts: mimicry and camouflage.

a. Mimicry enables an a. Mimicry enables an organism to copy the organism to copy the appearance of another species.appearance of another species.

b. Camouflage is a b. Camouflage is a structural adaptation that structural adaptation that enables an organism to blend enables an organism to blend in with its surroundings.in with its surroundings.

What evidences are there for evolution?

MIMICRYMIMICRY

CAMOUFLAGECAMOUFLAGE

Evidence of EvolutionEvidence of EvolutionPhysiological AdaptationsPhysiological Adaptations

7. 7. Some adaptations are Some adaptations are physiologicalphysiological or changes in an or changes in an organisms metabolic processes. organisms metabolic processes.

– Keep in mind that all things are made Keep in mind that all things are made up of cells and the organelles are up of cells and the organelles are structurally and functionally similar in structurally and functionally similar in most organisms.most organisms.

Physiological AdaptationsPhysiological Adaptations

• Organisms are constantly changing Organisms are constantly changing to to adapt adapt to their environment. Take to their environment. Take a look at organisms that have been a look at organisms that have been exposed to antibiotic and pesticides. exposed to antibiotic and pesticides. The organisms that survive have The organisms that survive have become selected because they are become selected because they are physiologically more physiologically more resistantresistant. .

Imagine that there are Imagine that there are 1010 bacteriabacteria growing on your hand. growing on your hand.

You use Germ-x to clean your You use Germ-x to clean your hand hand everydayeveryday..

After 4 days, there are still 3 bacteria After 4 days, there are still 3 bacteria on your hands that have on your hands that have survivedsurvived..

Is there anything special about these Is there anything special about these bacteria? bacteria?

Yes..they have something about their Yes..they have something about their DNA that has made them different and DNA that has made them different and

strong enough to survive. strong enough to survive.

So now what will happen?So now what will happen?

Those 3 that are “resistant” will Those 3 that are “resistant” will undergo undergo MitosisMitosis..

And after a week, your hands will be And after a week, your hands will be covered with tons of bacteria that are covered with tons of bacteria that are

ALLALL resistant to Germ-X. resistant to Germ-X.

evolutionary theory and evidence evolution notes part 1

Documents

disuse organisms

modern organisms

perfection organisms

group of organisms

organisms lifetime

traces of organisms

origin of species

darwins theorywhat