Evolution Flashcards
Who first conceived the theory of evolution?
Charles Darwin
What are the 4 basic principles of evolution/life
- traits must be heritable
- variation / genetic mutation must exist
- variations of a trait must provide an advantage for evolution to occur
- competition for limited resources
Combining the 4 principles of evolution, what is the theory of evolution?
the DIFFERENTIAL SUCCESS of certain VARIATIONS of a HERITABLE trait because of COMPETITION for limited resources
how does constitution of a new species occur?
organism accumulates so many new traits, that it is very different from the ancestor –> new species
How is it possible for a new species to evolve without the extinction of the ancestor?
small population of the ancestral species branches off because it is exposed to new environmental conditions that favoured new traits
What determines if a trait will be successfully passed on to later generations?
NATURAL SELECTION: competitive selective process by which detrimental traits are discarded and advantageous traits are retained (i.e. how well a trait improves an organism’s reproductive success)
How are organisms grouped together?
based on their most recent shared common ancestors
What is an example of dinosaurs that have been grouped together?
ornithischia: hadrosaurs, pachycephalosaurs, ankylosaurs, stegosaurs
What species did the dinosauria evolve from?
amniote tetrapod
What is a character?
any heritable trait that can be described and labeled
What is a shared derived character?
- character that may present in 2 or more groups and their common ancestor
- not present in any more distantly related groups
What is another name for a shared derived character?
synapomorphy
What is an example of synapomorphy in ornithischians?
predentary
What is the biggest challenge to determining evolutionary relationships?
convergent evolution
What is convergent evolution? provide an example.
- evolution of similar traits in 2 different lineages/species
- example: spinosaurus (theropod, saurischian) and ouranosauraus (igaunodont, ornithischian) both have a sail on their backs
When does convergent evolution usually happen?
when 2 lineages must adapt to similar environments and to similar modes of lige
What is an example of the convergent evolution of wings in flying vertebrates?
birds, pterosaurs, bats all evolved wings from the FORELIMBS but in different ways
pterosaurs: membrane wing, one long finger
bats (mammals): membrane wing, several fingers
birds: feathered wing, fused hand bones into single unit
the ouranosaurus has a sail like what dinosaur
Spinosaurus
which dinosaur does the ouranosaurus have the most common traits with and what are they
iguandonts
- grinding teeth and beak
-back facing pubis
- predentary bone
define parsimony
the idea that “all other things being equal, the simplest answer is usually the right one”
occam’s razor is also known as
parsimony
describe the processes involved in making phylogenic trees
- use computer program to determine evolutionary relationships between species
- analyze the list of characters -> character matrix
- application of the principle of parsimony to arrange organisms in a way that there are fewer instances of convergent evolution
- family tree is made
phylogenic trees are made of ___ and ____
nodes and branches
____ is where two branches diverge
node
what does a node tell us
shows the point at which two linages shared a common ancestor
species that share a common ___ is called a ____
node… clade
true or false - clades have a size limit
false - there is no size limit
what is the criteria for a clade
must contain the ancestor of a group and all its descendants
what class are four limbed animals part of
can be traced back to a fish ancestor -> class Pisces
what is the modern name for class pisces
Osteichthyes
define missing links
organisms that show evolutionary connection between two major groups of organisms by expressing traits of both groups
who is the earliest advocate for the theory of evolution
Thomas Henry Huxley
what did Huxley find out
he recognized that birds evolved from dinosaurs -> Achaeopteryx are a missing link between dinosaurs and birds
where were Achaeopteryx fossils preserved
lake deposits
why is the Archaeopteryx similar to both birds and dinosaurs
long wing feathers and tail feathers = bird
teeth, clawed fingers and a long series of tail vertebrae = dinosaurs
true or false - birds are part of the dinosaur family tree
true
what is the first non avian bird to be discovered with feathers
sinosauropteryx
define the differences between the modern bird and non avian bird
modern bird used feathers for flight, non avian birds used feathers for insulation
true or false - Yutyrannus was found to have no feathers
false - it does have feathers
what group does the Yutyrannus belong to
tyrannosauroid
____ are the only clade dinosaurs alive today
birds
true or false - birds are sauropods
false - they are therapods
the clade name for flying dinosaurs is
a) Aves
b) Avialae
c) Pisces
d) Avis
b
is the Archaeopteryx part of the Aves or Avialae group
Avialae
the Haplocheirus is a
a) hadrosaur
b) tyrannosaurid
c) alvarezsaur
c
the Dilong is a
a) hadrosaur
b) tyrannosaurid
c) alvarezsaur
b
what are the three dramaeosaur mentioned in the Ascent of birds are
Confuciusornis, Archaeopteryx, Xiaotingia
what kind of dinosaur is the Bohaiornis
enantiornthine
what are the two ornithurine dinosaurs mentioned in the Ascent of Bird
Asparavis and Ichthyornis
Archaeopteryx is more closely related to _____ than modern birds
dramaeosaurid therapods
what are the three hadrosaurs in the dinosaur park formation of alberta and what was found about them
Parasaurolophus(single elongated crest), corythosaurus(single crest) and lambesaurus (double crest)
what is a characteristic of the lambeosaurine hadrosaurs
have hollow crests on the top of their heads - shared derived character
what dinosaur is an early ceratopsian from the early cretaceous of china
liaceratops
ceratopsians with a nasal horn is called ….
ceratopsid ceratopsians
what is a shared derived character of pachycephalosaurs
thick domed skull
true moles are more closely related to _____ than true moles
elephants
parsimony is also known as
Occam’s Razor
are feathers a shared derived feature of birds
no because we know many dinosaurs have been found with feathers as well
