Download Other scientists support of evolution

EVOLUTION
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Change in a species over time
Diversity
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Huge variety of animal and plant life living organisms as well as fossils
Adaptation
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Plants and animals were well suited to the
environments in which they lived
• physical and behavioral traits enabled them to
survive
Galapagos Islands
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Finches: type of bird in the Galapagos
• isolated on islands so these birds demonstrated
the ability to adapt to environmental changes
• Rosemary and Peter Grant
Other scientists support of
evolution
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Anatomists: study of structure of adult
animals
Homologous Structures:
• similar bony structures in different organisms
• develop from the same type of tissue in an
embryo
Other scientists support of
evolution

Analogous Structures: similar in function,
but different in embryonic development
Other scientists support of
evolution

Embryology: looked at embryo’s of
different organisms and noted similarities
Other scientists support of
evolution

Vestigial Organs: structures that appear to
have lost their function in an organism
Other scientists support of
evolution

Geologic Explanations: the face of the Earth
can change, why not life on earth?
Darwin’s Findings

Overproduction: capacity of every species
to produce more offspring than can survive
• Fitness: species have to reproduce and pass on
their genes successfully to survive
Competition
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Struggle for existence
Between species
Within species
For food, water, shelter
Variation
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Differences between the members of a
species make every individual different
from every other individual
Adaptations
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“Survival of the fittest”
Those best adapted to the environment will
survive longer and reproduce more
successfully than individuals less adapted
Natural Selection
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Favorable variations will be passed on
Unfavorable variations will be eliminated
from future generations
Speciation
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Results from accumulated variations in an
isolated population: new species are formed
Each living species is descended from other
species over time and share a common
ancestor: ADAPTIVE RADIATION
How fast does evolution occur?
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Gradualism: occurs slowly over time
(millions of years): Darwin’s theory
supports this
Punctuated Equilibrium: species stays the
same for a long period of time. The
appearance of a new species disrupts the
balance allowing for a short period of rapid
evolution: Steven J. Gould
How Does Variation Happen?

Population Genetics:
• population: group of individuals of the same
species, living in the same locations and
capable of reproducing
• Gene Pool: mixture of all possible alleles
within a population
• can determine the frequency of any allele in a gene
pool (1 in one million to 100%)
How Does Variation Happen?
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Mutations: changes in DNA that changes
the information carried by the gene
• can be positive or negative mutations (may or
may not survive)
How Does Variation Happen?
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Gene Recombination: occurs during sexual
reproduction when genes from two parents
are mixed to produce offspring
How Does Variation Happen?

Migration: when an individual leaves a
population and moves to a new population
bringing their genes to the new gene pool
and taking away genes from the old gene
pool
How Does Variation Happen?

Genetic Drift: occurs in small populations,
not large ones
• bad because decreases the variation in the gene
pool
• if only a few organisms have certain alleles and
they are destroyed before they have reproduced,
the alleles are lost
How Does Variation Happen?
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Hardy-Weinberg Law
• does not exist in nature, just tells us under what
conditions we can stop evolution
• mathematical analysis of allele frequencies
• No evolution under the following conditions:
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population must be large
Individuals cannot migrate
mutations cannot occur
Reproduction must be completely random
Types of Speciation
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Isolation: something that prevents two
groups of the same species from
interbreeding
• new gene pools evolve
Types of Speciation
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Geographic Isolation: happens when a
species is separated by some natural barrier
such as a desert, mountain or body of water
• the species adapts to the environment in which
it lives
Types of Speciation

Reproductive Isolation: When a species
becomes separated, goes through evolution
and loses the ability to interbreed
Convergent evolution
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Organisms not closely related develop
analogous structures due to adaptation to
their environment
Coevolution
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When two species evolve in response to one
another either competitively or
cooperatively
• flowers and bees: flowers have adaptations that
attract bees
Bacterial Resistance to
Antibiotics
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Mutations have occurred in bacteria that
allow them to resist antibiotics and survive.
The bacteria that survive are able to
reproduce and pass on the mutation to their
offspring, creating a generation of bacteria
that are resistant to antibiotics
Scientists
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Stanley Miller and Harold Urey: 1953
• Simulated primitive conditions on earth to
create organic compounds
Heterotroph Hypothesis
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Lynne Margulis: U Mass Amherst
Primitive atmosphere: ammonia, methane,
water and hydrogen gases
Organic Compounds: Simple sugars and
amino acids formed by combining inorganic
raw materials in a “hot, thin soup”
• Aided by heat and electricity
Heterotroph Hypothesis
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Aggregates: clusters or groups of complex
molecules, absorbed simple organic raw
materials from the environment for food:
heterotrophs
Heterotroph to Autotroph: heterotrophs
performed anaeorbic respiration creating
CO2 because there was no oxygen in the
atmosphere
Heterotroph Hypothesis
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Increased amount of CO2 lead to evolution of
organisms who could use CO2 produce their own
organic compounds
 Anaerobes to aerobes: Once the organisms were
producing their own food through photosynthesis,
oxygen was added to the atmosphere and the
heterotrophic organisms evolved to be able to use
the oxygen to make larger amounts of energy than
they could using anaerobic respiration