Origin of Species Flashcards
What does the latin world for evolution (evolvere) mean ?
To roll out or away, unwrap, uncover, unfold
What is biological evolution ?
Descent with inherited modification. Ancestor to descendants.
Definition of Scientific Theory
An idea supported by observations or evidence from previous hypothesis testing to explain how a phenomenon happens.
What is the germ theory of disease?
Specific diseases are caused by specific microbes within the human or animal host
What are the three underlying principles of natural selection:
- Organisms have variation in their traits
2.Not all individuals will reproduce - Traits of survivors are inherited by offspring
What are the other 3 mechanisms of how biological evolution could happen besides natural selection?
-Mutation
-Migration
-Genetic Drift
What is the result of traits of survivors that are inherited by offspring ?
the traits that were more advantageous become more common in the next generation.
What are advantageous traits passed down also know as ?
Adaptations
What is an adaptation ?
a feature of an organism that is advantageous…it
helps an organism survive and/or reproduce in its current environment.
What does The Theory of Evolution by Natural selection attempt to explain ?
how evolution occurs by the process of natural selection
What is mutation ?
a change to the original sequence of an organisms genome
How can mutations occur ?
- Mismatched base pairs can happen
naturally during replication
2.Damage to DNA due to environmental exposures
(toxic chemicals, UV light, radiation)
Mutations only form in youth of organisms.
False (An individual can acquire a mutation during
their lifetime)
A mutation in a __________ cell would be
inherited by the offspring?
Why is a mutation a
mechanism of evolution ?
1.The trait (mutation) is a source of genetic variation in a
population (can increase variation)
2.If the trait (mutation) does not kill the individual, it has a chance to reproduce.
3.If the trait (mutation) is heritable, it can become more common in future generations
What is migration (gene flow) ?
Any movement of individuals, and/or the genetic material they carry, from one population to another.
Why is Migration a
mechanism of evolution ?
1.The introduced trait is a source of genetic variation
in a population (can increase variation)
2.If the introduced trait does not kill the individual, it has a chance to reproduce.
3.If the introduced trait is heritable, it can become more common in future generations
What is genetic drift ?
In every generation there are some individuals that are not able to reproduce for reasons that are due to chance.
The traits in a population may not necessarily the most “advantageous”.
Why is genetic drift a mechanism of evolution ?
- Is still a source of genetic variation in a population
(can increase the ratio of some traits, and decrease
the ratio of other traits) - Survivors still have a chance to reproduce.
- If the surviving trait is heritable, it can become more common in future generations
Adaptations are not required for evolution to occur.
True
What is descent with inherited modification ?
Change in gene frequency in a population from one generation to the next
What 2 things can traits be ?
Physical or behavioral
How are traits decribed as good or bad ?
- Advantageous
- Neutral
- Disadvantageous
How is it determined if the trait(s) are advantageous or disadvantageous ?
It depends on the specific environment
When there is a selective pressure present in
the environment.
the trait that helps the organism survive so that it can pass the trait down to its offspring is advantageous and will become the adaptation in the next generation
What is an adaptation ?
a feature of an organism that is advantageous…it
helps an organism survive and/or reproduce in its current environment.
What must something have for it to be an adaptation ?
must be advantageous and heritable
What is change due to in Natural Selection ?
environmental pressure that “select” for more advantageous traits
What is change due to in Mutation ?
Random change (random mutations) in DNA/genome
What is change due to in Migration (Gene Flow) ?
Movement of individuals with different traits from one population to another
What is change due to in Genetic Drift ?
Random chance event (accident, natural disaster, etc)
Assuming that a trait is heritable, which mechanism would result in an adaptation?
Adaptations results from natural selection.
Assuming the trait is heritable, which mechanism could result in an adaptation ?
Mutation. Migration (Gene Flow), and Genetic drift
What is adaptive evolution ?
- When evolution leads to an adaptation
*An organism is more fit for an environment
What is non-adaptive evolution?
- When evolution doesn’t lead to an adaptation
*Neutral or Disadvantageous
What is microevolution (small-scale evolution) ?
When a change in gene frequency occurs over a few generations.
What is macroevolution (large-scale evolution) ?
Evolution over long periods of time (thousands,millions,billions of years)
Population (bio definition)
A group of organisms that interbreed with each other- they all share a gene pool
Common definition of Species
a group of individuals that actually or potentially interbreed in nature and produce sexually viable offspring
Speciation
a formation of a new species
* lineage splitting event that produces two or more separate species
What are the 2 different speciations ?
- Allopatric speciation
-Sympatric speciation
What is allopatric speciation ?
Geographic isolation reduces gene flow (physical)
What is sympatric speciation ?
Non-geographic isolation reduces gene flow (biological/behavior)
What are the 2 timelines of how speciation occurs ?
Gradualism
Punctured Equilibrium (rapid change/catastrophsim)
