evolution Flashcards
(20 cards)
what is evolution
the gradual change in a species over time
what is natural selection
mechanism which brings about that change
what did Darwin do/not do
-didn’t come up with the theory of evolution
-instead, established the mechanism by which it took place
how did Darwin come up with this theory of natural selection
visited Galapagos islands and observed variation between members of the same species on diff islands
who else supported Darwin’s research
Wallace - a naturalist who came to the same conclusions that Darwin did, found the same findings as Darwin on natural selection
four main ways that Darwin formulated his theory (without any molecular evidence)
-Living species
-Fossils
-Comparative anatomy
-Artificial selection
how did living species help Darwin formulate his theory
-noticed different finches on the Galapagos with different beaks, some has strong beaks and others had delicate (based on food)
-thought all finches could have evolved from one species with a generalised beak shape
how did the use of fossils help Darwin formulate his theory
-fossil record revealed many ancient organisms appear to be transitions between different animal groups
what were the three conclusions that could be drawn from using fossils
-in the past existed species different to those present today
-old species died and new ones emerged
-new species often show similarities to those that have died out
how did comparative anatomy help Darwin formulate his theory
-similarities between the anatomy of different animals can show that they may have common ancestry
how did artificial selection help Darwin formulate his theory
-domestication of animals shows animals can undergo dramatic changes
-animals have been selectively bred for centuries leading to a wide range of dog breeds, etc.
what were Darwin’s four observations
1.more offspring made than can survive
2.populations remain stable over time
3. there is variation in a population
4.variation is heritable
what does more offspring made than can survive tell us about evolution
-struggle for existance
what does populations remain stable over time tell us about evolution
-competition for limited resources maintains this stable population size
what does variation in a population tell us about evolution
-differences may affect competitiveness
what does variation is heritable tell us about evolution
adaptations can be passed on, letting species evolve gradually
what is the modern evidence for evolution
biological molecules
if one species is the ancestor to another, what may they share?
share some of the same biological molecules
how do biological molecules show evidence for more recent separation of 2 species
-biological molecules more likely to be identical/very similar if they are more recently separated
example of biological molecules
-cytochrome C and other proteins show pattern of changes when we analyse sequences of AA found in their structures
-DNA gene comparison by sequencing bases of DNA- more similarities is more closely related
