BIO1040 Exam 2

complex systems

new genes evolve new functions
old genes take on new functions

genetic toolkit

different animal body plans are built with the same basic

homeotic transformations

one body part replace another
certain mutations most common in parts of the body that were either repeated

evo-devo

variations in structures depend in part on when and where certain genes are expressed
also called molecular paleontology

homeotic genes *

control foundation of tissues
act as signals that create a sort of instructional map for where structures should develop

homeotic genes cont.

affects phenotype and is which natural selection acts

hox genes *

homeotic genes in animals
position on chromosome correlates to the relative position on the animal body part that it regulates

deep homologies *

genes responsible for prominent and widely divergent traits come from a common ancestor
pax6 is an example (eye sensor)

photoreceptors

captures light

ancestors of opsins

receptor for the hormone melatonin
act as sensors grabbing molecules passing by and relating signal inside the cell

evolution is tinkering not engineering *

does not improve organisms to perfection
well enough traits will be selected
phenotypes are results of trade offs and physical constraints

trade-offs *

birds: trade off between total field and range of binocular vision
owl (high binocular low monocular)

costly

sexual reproduction is

benefits of sex *

speeds up pace of adaptation
cannot separate bad mutation from good in asexual reproduction
sexual combines genotypes in each generation into new combinations

Muller ratchet *

purges deleterious mutations - sexually produced offspring are genetically different from their parents
recombination creates two new variants, which reduces deleterious mutations

Red queen hypothesis *

allow rapid evolution response to parasites predators

Fisher-muller hypothesis

generates genetic variation that is favored by natural selection accelerates adaptive evolution
bring 2 beneficial mutations together

sexual dimorphism *

systematic difference in form between individuals of different sex in the same species
suggests sexual selection affects organisms differently
ie: big spider female, and small male
persuades members to mate

sexual selection *

traits that better help attract other members to reproduce

female parental investment *

increase relative fitness of young receiving
reduces reproductive potential of parent giving it

intersexual selection*

males showw off color, behaviors; females choose the most attractive

intrasexual selection*

male to male competition and female have no right to choose

female choice drives evolution and showy traits

traits become exaggerated
trade-offs
ie: sperm battles

sexual conflict

increases fitness of male and lowers reproductive success of females

species *

fundamental units of organism diversity

species diversity

half known species are insects

recognizing species

survival depends on our ability to recognize species

origin of species*

direct result of evolution

biological species concept

useful due to focusing on the process of how species form
hybrid problem still exist

allopatry speciation*

geographical barriers preventing from interbreeding
physical separated

parapatric speciation*

biological barriers
food preferences, spawn time etc
occurs in a hybrid zone

sympatric speciation*

species diverge while inhabiting the same physical space
resource competition and reproductive isolation

hybrid zone*

areas of contact between 2 diverging population where hybrids are common
disapproves when speciation is complete

reinforcement*

when NS acts to increase the amount of reproductive isolation between population

ring species*

population at both ends of a range grow more different from each other due to some factors (cannot interbreed due to genetic divergence and therefore leading to reproductive isolation)

phylogenetic species concept*

2 organisms with different evolution history are different species
cons: requires comprehensive analyses
pros: testable, objective and applicable

macroevolution

history of biodiversity
process of organization, adptation, and extinction

biodiversity

increases if rate of origination increase
increases if rate of extinction decrease

biogeography*

study of how continental drift affect organisms

vicariance*

physical barriers affecting organisms overtime

punctuated equilibrium*

evolution is not slow and steady
can be small bursts often associated speciation event

adaptive radiations*

dramatic bursts of evolution and lead to convergent evolution
endemic species - found only in a certain area due to the particular niche

three groups of fauna

cambrian - both high origination and extinction rates
paleozoic - lower origination and extinction rates
modern - lowest origination and extinction

the big five mass extinction events*

permian and triassic 252 mya (96 percent were gone)
could be caused by volcano eruption
most recent is 66 mya caused by asteroid

dinosaurs*

not extinct, but birds now

coevolution*

the reciprocal evolutionary change between ecologically intimate species
one species may cause selection to operate in new ways on the other

mutualistic interactions*

both species benefit from the interaction
must involve substantial genetic modifications in both partners

antagonistic coevolution*

evolutionary changes in each species decreases the fitness of the other species

cospeciation

speciation in one species leads to speciation in the other
caused by high benefits and long term mutualistic relationship

obligate mutualism

each partner can only survive and reproduce successfully in the presence of the other
often leads to cospeciation

cheaters

reap the benefits of cooperation without having to pay the associated costs

antagonistic coevolution*

predator prey and parasite host e

evolution arms race*

evolve at the same tiem to survive

mimicry*

one resemble another so predator is confused

aposematic

warning coloration

batesian*

share looks but no defensive attribution

mullerian*

share looks with defensive attribution

coevolution

___leads to dependence and can lead to extinction

cultural transmission*

when learning from others, information spreads through the population quickly

cultural evolution

when cultural transmission leads to changes in the frequency of traits