Theory of evolution Evolution is the changes that occur in organisms characteristics over time...
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Transcript of Theory of evolution Evolution is the changes that occur in organisms characteristics over time...
Theory of evolution
• Evolution is the changes that occur in organisms characteristics over time
• Change in a species due to mutation of the DNA code that occurs over a long time
An example ofEvolution
An example of Evolution
An example of Evolution
The Theory of Evolution by Natural Selection
• Charles Darwin theory of evolution through natural selection is the most widely accepted theory
In 1831, Darwin set sail on the ship The Beagle, at age 22 . He studied plant and
animal life of the pacific islands and South America
Galapagos Island- observations of the animal and plant life
here helped Darwin support his theory of Evolution
through Natural Selection.
His greatest work came from his work with finches
30 years after Darwin’s voyage he wrote a book The Origin of species by means of natural selection. (1859)
None of these conclusions by Darwin
have ever been disproved.
Natural Selection
Darwin’s theory of evolution through Natural
Selection has 4 main
concepts
All organisms tend to over reproduce.
In any population of organisms individuals will exhibit slight
variation.
All organisms face a constant struggle for survival
Individuals with variations that are favorable for a particular
environment are more likely to survive and pass on those
favorable variations to the next generations
Gradually all offspring of the survivors will make up a larger proportion of the population.
Over many years a population may come to look the same.
Evidence of Evolution
1-DNA sequencing
2- Fossil evidence
3-Adaptation
4- Structural Similarities
5- Embryological Similarities
Evidence of evolution
1-DNA sequence – by comparing the DNA patterns in organisms scientist can determine which organisms are closely related
Evidence of evolution
2-Fossils studying and observing fossils help determine how organisms have evolved
•
Plant Fossil Evidence:
EVIDENCE OF EVOLOTION3-Adaptations: feautres suited to a particular environment that allow organisms to survive
Inuit people, who live in the extreme cold of the Arctic, have short, stout bodies that conserve heat.
Evidence of evolutionMasai people, who live in the arid lands of eastern Africa, have tall, lean bodies that disperse heat well.
Plant Adaptations:
Venus Fly Trap
• Captures Animals
• Acquires Minerals
• For Photo-
synthesis
Help!!!
Evidence of evolution
• Embryological development- as the egg is fertilized the developing organisms show similar patterns of embryological development
Evidence of evolution
1. Anatomical similarities – similar body structures
2. Homologous structures- same origins-different functions
3. Analogous structures- different origins- same functions
4. Vestigial structures- no longer useful
Evidence of evolution• Structures on different organisms are homologous when
they have similar base structures but have different functions.– Human Arm – Bat Wing – Whale Flipper
Evidence of evolution• Analogous structure- structures in different
organisms that have the same functions and are different in structures. Probably had different ancestor ( origins) .
Results of Evolution by way of Natural Selection
• Because of evolution the following results• A) Organisms are strong and fit • B) Speciation occurs – new organisms are
formed
Speciation
• How does Speciation occur?
1.Geographic isolation 2.Divergent evolution 3.Convergent evolution 4.Gradualism 5.Punctual equilibrium
Geographic Isolation
• Separation of organisms by geographic features
• Mountains• Lakes, oceans,
rivers• Deserts(May result in new
species over time)
Gradualism
• “gradual”
• Small changes
• Over a long time
Punctuated Equilibrium
• “punctuation!”
• Large changes
• Happen rapidly
• Periods of no change
• Gradualism: • Punctuated Equilibrium
Time
#SPECIES
• Divergent evolution- organisms that were similar in structure change and become a new species because the organisms changes to fit and survive in different environments
Divergence
• “diverge”= branch off
• Homologous structures
• Same origin• Same underlying
structure• Difference
functionsOriginal Species:
Mammal
Whale flipper
Human arm
Bat wing
Cat limb
Different origins but have same
features
• Convergent evolution organism that are different and unrelated change and develop similar body structures in order to survive in the environment
•
Convergent EvolutionPlacental mammals
Marsupial mammals