L17 INTRO. TO EVOL. Flashcards
Define evolution.
Evolution is the theory that modern organisms descended from ancestral species.
What is natural selection?
The mechanism for evolutionary change within a population.
What is meant by evolutionary adaptation?
An accumulated inheritance of favourable traits/characteristics that increases survival and reproductive abilities.
How did Aristotle view species and populations?
He viewed species as fixed & unchanging, and arranged species on a ladder of increasing complexity called the Scala Naturae, consistent with the Old Testament views of life.
Why was Linnaeus significant? What ideology did he follow?
He was the founder of taxonomy. He based his groupings on patterns of creation.
Who was Cuvier? What did he contribute to theory of evolution?
Cuvier was a french scientist who studied fossils and found that the older the strata, the more dissimilar the fossils, suggesting catastrophism as an evolutionary mechanism.
What is catastrophism?
The theory that sudden & violent occurences in early life caused evolutionary change/destroyed certain species.
Why was Malthus significant?
Malthus wrote his book Essay on Population, and noted that only a fraction of any population will survive due to populations gwoing exponentially faster than the food resources available.
He argued famine, war and disease will limit growth.
Who was Lamarck?
Lamarck proposed the theory of evolution through 2 main principles: use&disuse of morphological structures, and acquired traits. He wrongly theorized organisms could eventually reach perfection through these two mechanisms.
What is artifical selection?
The breeding of organisms to create new species through human selection of organisms with desired traits.
Who were Hutton & Lyell?
They were geologists that suggested slow and continuous processes led to profound change. They theorized that the earth must be much older than the 6000 years stated in Old Testament.
What was the basis for Darwins theory of evolution?
His 5 yr. voyage to South America & South Pacific.
What did Darwin observe on his voyage? What did he hypothesize?
Observed various adaptations of plants and animals based on their location. He then hyothesized that the species diversified due to environmentl differences (migrating to different islands).
Who is Alfred Wallace?
Wallace was another scientist who also theorized evolution via natural selection shortly after Darwin.
What are the four mechanisms for natural selection?
- Overproduction of offspring
- Limited resources and subsequent competition
- Heritable variations
- Differential reproductive success.
What is differential reproductive success?
Individuals with beneficial adaptations are more likely to survive to pass on their genes.
What is Darwinian Fitness?
The idea that an organisms reproductive success makes them fit, and the more offpring they can produce the fitter they are.
What are the two linked processes of evolution?
- Random generation variability
- Selection of “suitable” characteristics
What are the six scientific pieces of evidence suporting the theory of evolution via natural selection?
- Direct observation of evolutionary change
- Homology at the anatomical, developmental and molecular levels.
- Convergent evolution
- Fossil record evidence
- Biogeography
- Bad design
What is a vestigial structure?
Vestigial structures are seemingly
useless organs or are structures that
no longer performs the function for
which it evolved for.
What is molecular homology?
Similarities at the molecular/DNA sequencing level. Nearly all organisms follow a similar genetic code.
What is convergent evolution?
Convergent evolution is the independent evolution of similar features in species of different periods or environments.
Convergent evolution creates XXXX structures.
Analogous.
What are the four reasons for natural selection being unable to shape perfect organisms?
- Modifications possible on existing genes only.
- Historical constraints
- Adaptations are often compromises
- Chance, natural selection and the environment all play a role.
Fill in the blanks.
Analogous structures share similar function BUT NOT common ancestry.
Fill in the blanks.
Homologous structures share common ancestry BUT NOT common functions.
