Evolutionary Thought and evidences of evolution Flashcards
any net directional change or
any cumulative change in the
characteristics of organisms or
populations over many
generations
Evolution
He said that Species are identical. They
tend to remain the same
species and can be
arranged hierarchically.
Aristotle (350 BCE)
He said that As species change, they migrate to
another environment resulting in
their distribution.
Georges-Louis Leclerc, Comte de
Buffon (AD 1749)
He said that Species evolved from existing
species through environmental
forces. Trait can be passed to
the next generation.
Jean-Baptiste Lamarck
(1809)
Thought the idea of descent
modification
idea that species change over
time, give rise to new species, and
share a common ancestor.
CHARLES DARWIN
(1874)
He stated that All changes in the environment are
uniform and gradual.
Charles Lyell (1830)
He Realized that species evolved
because fittest individuals
survived and reproduced passing
their advantageous characters
ALFRED WALLACE
(1823)
What are the theories of evolution?
- Theory of acquired characteristics
- Theory of need
- Theory of use and disuse
- Survival of the fittest
·Sometimes called the theory of inheritance
of acquired traits, or “soft inheritance.”
·Holds that an organism experiencing such
a modification can transmit such a character
to its offspring.
Theory of acquired characteristics
A Theory that states Changes in the environment can raise new
needs, required for species’ survival.
Theory of need
·Parts of the organism that is regularly used
will undergo hypertrophy and will be
developed.
Theory of use and disuse
·Organisms adapt to their environment and
survive.
·Descent with modification – species has
descended and changed over time.
Survival of the fittest
What are the mechanism of evolutionary changes?
- Geneflow
- Genetic Drift
- Founder effect
- Bottleneck effect - Natural selection
- Non-random mating
- Mutation
is a change in the gene
pool of a population due
to chance.
Genetic drift
it takes place when population
decreases due to various environmental factors
such as fires, earthquakes and floods.
Bottleneck effect
it happens when a small
population of organisms separates from the
larger group to invade a new area.
Founder effect
described as the
movement of genes
from one population
to another. When
this happens, there
is a tendency to
increase the gene
diversity in the
populations.
Gene flow
Occurs when there is a change in the genetic makeup
caused by environmental stressors. Expands diversity of
organisms.
Mutation
explains the difference in survival of individual and
reproduce in a particular environment.
Natural selection
increases the
frequency of animal
with desirable traits.
It causes evolution
because it intrudes
the natural pool of
gene variations.
Non-random mating
What are the evidences of evolution?
- Fossil record
- Biogeographical
- Anatomical
- Biochemical
It provides information about past organisms. It also shows that many diverse organisms lived at different times in earth’s history.
Fossil record
These distributions
are influenced by
many factors,
including continental
drift, the slow
movement of Earth’s
continents over time.
Biogeographical
Anatomically similar because they are inherited from a
common ancestor
May be functionally similar or not
Homologous structure
Serve the same function
Not constructed similarly
Do not share a common ancestor
Analogous structures
Fully-developed anatomical structures
Reduced or obsolete function
Vestigial Structures
Homologous structure : _______ evolution
Anatomical structure:
______ evolution
Divergent ; Convergent
It is when two species or populations evolve to become more different from each other.
Divergent evolution
The independent evolution of similar features in different lineages
Convergent evolution
anatomical
feature that no
longer seems to
have a purpose
in the current
form of an
organism of the
given species
Vestigial structures
The strongest and absolute
evidence that we have to support
common ancestry is the DNA
that we share.
Comparing sections of DNA in
difference species has shown that
even organisms that seem to be
different, actually have large
sections of identical DNA
Molecular evidence from DNA sequences (Biochemical)
DNA analysis - ____
Gel Electrophoresis
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