Quiz One Semester Two Flashcards
what is speciation?
the formation of new species
what must happen for speciation to occur?
The gene pools of two populations must become separated/reproductive isolation must occur
In what ways can reproductive isolation develop?
behavioral isolation, geographic isolation, temporal isolation
behavioral isolation
occurs when populations have different courtship rituals or other behaviors involved in reproduction.
geographic isolation
Occurs when geographic barriers such as mountains or rivers separate populations
temporal isolation
occurs when populations reproduce at different times
struggle for existence (how does it relate to Darwin?)
More individuals are born than can survive, and organisms must compete for resources, food, and mates
Variation (how does it relate to Darwin?)
Natural variety of traits among organisms. Necessary for natural selection to occur.
Artificial Selection
Selective breeding by humans of plants or animals to promote the occurrence of desirable traits in offspring
Natural Selection (how does it relate to Darwin?)
- Process by which organisms that are most suited to their environment survive and reproduce most successfully; also known as survival of the fittest
- Natural selection occurs in any situation in which more individuals are born than can survive, and there is natural variation and varying fitness among individuals.
Biogeography (how does it relate to Darwin?)
- Study of the past and present distribution of organisms
* Patterns in the distribution of living and fossil species tell us how modern organisms evolved from their ancestors
Hutton (how does it relate to Darwin?)
- Hutton recognized the connections between geologic processes and geologic features like mountains, valleys, or layers of rock that appear to be folded
- Introduced a concept called deep time that our planet’s history stretches back over a very long period of time
Lyell (how does it relate to Darwin?)
- Argued that the laws of nature are constant over time and that processes that occurred in the past can be explained by events that occur in the present
- Also believed in deep time
Malthus (how does it relate to Darwin?)
- Reasoned that if the human population grew unchecked, that there wouldn’t be enough living space and food for everyone
- This influenced Darwin’s thoughts about how and why species evolved over time
Divergent Evolution
This type of evolution begins with a common ancestor. Organisms evolve characteristics all based on the same ancestor, but they adapt traits into different forms or variations
Homologous characteristics
structures that are similar in different species of common ancestry
Convergent Evolution
Process by which unrelated organisms independently evolve similarities when adapting to similar environments
Analogous structures:
body parts that share a common function, but not structure
Comparative embryology/molecular biology
Similar patterns of embryological development provide further evidence that organisms have descended from a common ancestor
Molecular evidence (modern synthesis)
At the molecular level, the universal genetic code and homologous molecules provide evidence of common descent
Comparative anatomy
oOrganisms that have similar anatomy may reflect a shared common evolutionary history
oPeople, when looking at comparative anatomy, are looking at homologous characteristics, traits that evolved through divergent evolution
Vestigial Characteristics
reflect divergent evolution and a common evolutionary past, but they have lost their form and function in the modern organism. The traits just haven’t been lost because there have been no pressures for this to occur.
Darwin
The theory of natural selection
Alfred Wallace
Wallace was the instigation that forced Darwin to publish his ideas, otherwise, they would be credited to Wallace, who previously read Darwin
Adaptive radiation
As an original species becomes geographically separated, descendants of the same original species adapt different traits for their specific environment
