Weeks 7-8 Flashcards
what 4 things do all chordates have
tail
pharengyl slits
notochord
dorsal hollow nerve chord
what characteristic do tunicates retain from chordates
pharengyl slits
what are some cold adaptions
fur, feathers, blubber, thermoregulation
what are some hot adaptions
amniotic egg, scales
what is an adaption
a trait that becomes common in the population bc their offspring have more individuals
what did the earliest vertebrates evolve to protect their nerve chord
prong like extensions (catilage)
what is the primary function of the vertebral column
protect the nerve chord
what did fish evolve for more O2 absorption (gas exchange)
lungs/swim bladders
what is the structure that prevents dehydration, helps gas exchange, transfers nutriens, is a shock absorber, and for waste storage
amniotic egg
what stage does the amniotic stage eliminate and why
the larva stage, because it allows the mother to lay on the egg
what do scales, claws, hair and feathers help the animal do
conserve water
conserve body heat
defence
camoflage
what are some characteristics unique to mammals
female nourishes young w milk glands
generates own heat (endothermic)
give birth to live young
hair+fat to protect from heat+cold
kidneys conserve water+remove waste
what is modern evolutionary synthesis
combines natural selection + mendelian inheritance + modern genetics
what components make up modern evolutionary synthesis
selection pressure
spon mutations and sexual reprod.
mendelian inheritance
other (genetic drift / gene flow)
what is selection pressure
competition, predation, environment, non-random mating
what do we need to set up a hypothesis + what is this called ?
background info
observations
general theories
conclusion from previous data
- also need a control
“deductive reasoning”
TF we want to collect all of the organisms of the species on the island to study
F, we want to collect as large of a sample size given time and funding restrictions
what is inductive reasoning
a conclusion based of specific data (or data that you have collected)
what is microevolution
natural selection - certain trait changes - happens within 1 species
what is macroevolution (speciation)
difference in phenotype of 1 species becomes so different that that the 2 populations can no longer mate and the species splits into 2.
what are 3 natural selection characteristics
inheritable traits
variation among individuals
selection pressure
which ways can natural selection affect/shape a population(what are the types of natural selection
stabilizing selection
directional selection
diversifying selection
frequency dependent selection
sexual selection
what is stabilizing selection
being average is good
extreme traits selected against
ex) # eggs a bird lays
what is directional selection
selects for extreme phenotypes depending on environment
ex) beak size before vs after a drought
what is diversifying selection
2 or more phenotypes where the intermediate is less fit (selection against the average)
ex) bunny colour
what is frequency dependant selection
+ve = favours common phenotype
-ve = favours rare phenotype
ex) +ve elk - fit in w crowd (camoflage)
-ve - attracting a mate, maybe viruses dont recognize a binding site
what is sexual selection
- have physical structure to attract mate
- intersexual vs intrasexual
- has to do w enviro + weather or not they have to defend something(for females)
what is intersexual
Just have to look good to attract a mate
what is intrasexual
defend something for the females to attract a mate
what is genetic drift
evolution due to chance events
ex) hurricanes/floods
what are the 3 situations (effects) for genetic drift
(all by chance)
-bottleneck effect - individuals die due to environmental event (nat. disasters)
-effect of random mating - some individuals will have more offspring than others
-founder effect - some individuals migrate to new island
what is the problem with genetic drift
reduces variation
whats the difference between nat. selection and genetic drift
drift = random
selection = not random
TF in a smaller population the likelihood of an allele being fixed is lower
F, its higher (1 trait remains in the population)
TF small population w random mating = likely genetic drift + loss of an allele
T
why is high genetic diversity beneficial
adaptive capacity
potential long term survival
high resiliance
TF in large populations random mating leads to genetic drift and the loss of an allele
F
what 4 things increase genetic diversity
mutations
sexual reproduction
HGT
migration/gene flow
what are 4 things that show evidence of evolution
fossils
homologous + analagous structures
genetic similarities(best one)
vestegial structures
why is genetic similarities the best evidence of evolution
we can calcualte the genetic equivalence between animals
what is divergent evolution
the function of homologous structures may differ in different species
TF the limbs of a tetrapod are all homologous
T
what are homologous structures
structures in different species that derive from a common ancestor
what are vestegial structures
derive from common ancestor but have no apparent function in some species
ex) hind legs of snakes
what are analogous structures
species with similar adaptions (face similar selection pressure) but have no related lineage ex) bird wing vs insect wing
TF although the wings of birds and bats are analogous structures - the bones that make up those wings are homologous
T
what is convergent evolution
birds and bats evolving their ability to fly independently but due to similar selection pressures
TF convergent evolution results in analogous structures
T
