Evolution Flashcards
Charles Darwin
British naturalist that came up with the theory of evolution.
What does the theory of evolution explain?
How new species come into existance, how organisms become adapted to their enviroments, and why specific groups of organisms share specific traits
What 4 basic principles of life is the theory of evolution based on?
- heritable traits (traits that can be passed from parent to offspring
- variation of traits (there must be trait variation in the population)
- Advantage (the trait must provide an advantage over other traits)
- Competition (naturaenviroments have limited resourses that can limit an organisms ability to reproduce)
Evolution (definision including 4 principles)
The differencial success of certain variations of a heritable trait, because of competition for limited resources, leads to the change over time (evolution) of that trait in a population. This new trait improves the organisms ability to successfully survive and reproduce.
Clade
A group of species that shares a common ancestor (or a group of species that share a common node on a phylogentic tree)
Does evolution of a new species require the extinction of its new ancestor?
No.
Is evolution random?
No
Natural Selection
The competitive selective process by which detrimental traits are compeditively discarded and advantageous traits are retained
How are organisms grouped together?
By their most recent common ancestor
Ornithischia
“bird hipped”; pubis extends downwards and backwards
includes hadrosaurs, pachycephalosaurs, certatopsians, ankylosaurs, and stegosaurs
Saurischians
“lizard hipped”; pubis extends downward and forward twoard the ribcage
includes theropods and sauropods
What is the common ancestor of all of the dinosaurs?
Dinosauria
Character
Any heritable trait that can be described and labeled
Synapomorphy
aka… shared derived character
A character that is prescent in 2+ groups and their common ancestor but is not present in any more distantly related groups
What is an example of synapomorphy from the notes?
The predentary bone (beak) of the lower jaw in ornithischians.
Convergent evolution (plus example from notes)
The evolution of similar traits in 2 different lineages (unrelated)
The long vertebrate process of Spinosaurus and Ouranosauras (iguanodont dino)
What is a good example of convergant evolution?
Development of wings in different animal groups (birds, bats, etc)
When does convergant evolution normally occur?
When 2 lineages must adapt to similar enviroments and to similar modes of life
Parsimony
Occam’s razor; the idea that “all other things being equal, the simplist answer is usually the right one”
What does parsimony say when making phylogentic trees?
The phylogenetic tree with the fewest evolutionary changes is probably the right one
Node
Where 2 branches diverge on a phylogentic tree and shows the point at which 2 linages shared a common ancestor
What must a clade contain?
The ancestor of a group and all of its decendents
Thomas Henry Huxley
Colleague of Charles Darwin that recodnized birds evolved from dinos
Archaeopteryx
“missing-link” between dinos and birds
This specimen shows that Archaeopteryx has long wing-feathers and tail feathers just like a bird, they had teeth, clawed fingers, and a ong series of tail vertebrate just like a dino.
Huxley used this dino as evidence for his theory
Sinosauropteryx
A littlenon-avian dino that was discovered with feathers that had a simple structure compared to the feathers of modern birds and were used for insulation
Yutyrannus
Large tyrannosauroid that also had feathers
Are feathers a synapomorphy of birds?
No
