Topic 5: Evolution by Natural Selection Flashcards
(36 cards)
what were the key ideas before Darwin came around?
- species do not change over time
- Linnaeus classification is widely accepted
- taxonomy is considered the best method
what were Lamarck’s key ideas?
- species change over time but do not die out due to extinction
- species change from simple to complex until “perfect”
- species “evolve” through inheritance of characteristics that are acquired through the lifetime of individual
what is Lamarckism?
- species “evolve” through inheritance of characteristics that are acquired through the lifetime of individual
why was Lamarck’s theory not plausible?
-he didn’t really have any supporting evidence
- no mechanism explained
what were Lyell’s key ideas?
- uniformitarianism
- gradualism
what is uniformitarianism?
same natural laws govern the natural process in modern day and throughout the history of life
what is gradualism?
geologic features are formed by slow and continuous processes
what were Cuvier’s key ideas?
- species do not change over time
- different species documented in Earth’s history until present time are results of multiple extinctions (catastrophism) –> considered totally new species appearing after extinction
what is Cuvier considered the father of?
- comparative anatomy
- vertebrate paleontology
what were Richard Owen’s main ideas?
- species change over time
- mechanism for changes does not exist (it happens because god said)
- defined homology and the archetype for vertebrate
what was Darwin doing on the HMS Beagle?
- observe biological species and geological principles around the world and collected many natural specimens and fossils
when did Darwin propose the idea of natural selection?
1844
who was Darwin working together with for a more comprehensive theory of natural selection? and in what year?
- Wallace
- 1858
in what year was Darwins “On the Origin of Species” published?
1859
what were the key ideas highlighted in Darwins “On the Origin of Species”?
- species demonstrate patterns of “descent with modification” from common ancestor
- natural selection is mechanism for “descent with modification”
what were Darwin’s finches on the Galápagos Islands famous examples for? (four key terms)
- unity of organisms
- diversity of organisms
- speciation
- adaptation
what does “unity of organisms” mean?
similar traits among organisms due to descent from shared ancestor
what does “diversity of organisms” mean?
different traits among organisms due to changes in heritable traits
what does “speciation” mean?
origin of new species diverged from ancestral species
what does “adaptation” mean?
inherited characteristic of an organism that enhances its survival and reproduction in a specific environment
what did Darwin think about the finches?
- finches on the different islands are still somewhat similar, despite having a few distinct traits
what are the two observations leading to natural selection?
(1) individuals have multiple heritable traits of characters
(2) populations produce more offspring than the environment can reasonably support. most offspring do not survive to reproduce
what are the two inferences leading to natural selection?
(1) for a given population in a given environment, individuals leave more offspring, if their inherited traits give them a higher chance of surviving and reproducing (better for competing for limited resources)
(2) as some traits are better suited to a given environment, the unequal ability of individuals to survive and reproduce would lead to accumulation of traits favoured by the specific environment
what does “selective pressure” mean?
- environmental and biological factors acting on populations to influence the survival and/or reproduction of individuals in the population
