Evolution Flashcards
What is taxonomy?
A way to understand how organisms are related and a way to organise and categorise based on common descent
What is the classification system?
Kingdom Phylum Class Order Family Genus Species
What are splitters?
If they can’t tell two animals apart will put them in different species
What are high levels of synonymy associated with?
High levels of morphological variability
Large geographical ranges
What are the five kingdoms?
Animal Plant Protist Fungi Monera
How do heterotrophs get food?
Absorption, ingestion and digestion
How do autotrophs get food?
Make it via photosynthesis
What is microevolution?
Change in allele frequency over generations, associated phenotypic changes and changes within species
What’s macroevolution?
Changes above species level eg speciation
Or the emergence of flight
What is descent with modification ?
Descent from a common ancestor
Adaption to environment generating diversity and adaptedness
What’s artificial selection?
Humans creating an environment to favour selected traits
What did Malthus believe?
Most of human suffering due to limited resources
Factors of natural selection
Environment imposed challenges for survival/reproduction Variation Best genes move on to next generation Not random Selection biased
What is fitness?
Potential for reproductive success, producing young that survive to breed themselves
What’s special about the Nara nettles?
Have more stinging leaves to defend against deer
What happened to Galapagos finches after a drought?
Bill morphology
Larger seeds left so birds with larger bills selected for
What’s sexual selection?
Where various factors like avoiding predation, outcompeting rivals and ability to find food influence reproductive success
What’s Batemans principle?
Males must compete to mate with females, females are choosy and select the higher quality male
What does females choose males for?
Strongest
Resistant of disease
Those that will provide ‘sexy sons’ - reproductive success is higher
Males advertise via?
male ornaments, contests
nupital gifts
prolonged courtship
honest advertising of quality
what are male secondary sex characteristics?
sexual dimorphic, appear following maturity
sexually selected - males where these traits are more pronounced leave more offspring
whats runaway sexual selection?
explains the elaborate and costly male ornaments, positive feedback
strong enough female preference can counter natural selection
what do honest signals advertise?
strength, vigour = fitness
what is the benefit of females mating with multiple males?
choice, sperm will be in competition with each other to fertilize the egg
how can females choose sperm?
increase likelihood of a certain sperm, slowing or killing non-preferred sperm e.g close relatives can help best choice fertilize the egg
what is sexual selection?
those that have greatest fitness will survive to reproduce and mate, greater attraction, greater likelihood of getting the mate
how can we study natural selection?
make predictions about evolutionary responses
why are guppies important?
model organism in evolutionary ecology
why do guppies have colourful markings or not?
predation - if predators more likely to see and eat colourful ones why be colourful?
sexual selection - stronger in low predation areas
why do sexual and natural selection conflict?
sexual favours elaborate traits, this makes it easier to be seen/eaten
what happens to guppies in high predation areas?
females relax their sexual preferences - accept males with less colorful markings
what influences reproductive success?
age, size, longevity, no. offspring and quality of offspring per clutch
whats good about shoaling?
anti predator behavior
morphological definition of a species?
shape or form of body parts
ecological definition of a species?
species may interbreed but may supply different niches
how do species form?
gene flows diverge, speciation, populations accumulate differences via mutations so become different, gene flow counters this
what are reproductive barriers?
without gene-flow small mutations add up until members of the two populations can’t interbreed
what is allopatric speciation?
gene flow prevented when populations becomes separated by geographical barriers
once separated populations diverge and natural selection plays a role
whats genetic drift?
change in frequency of an allele in a population due to random sampling
when pop divided each might not have representative sample of genetic diversity - especially if small
what drives speciation?
physical and behavioural reproductive barriers
what’s sympatric speciation?
reproductive barriers leading to subset of population not mating with other subsets
whats polyploidy?
speciation occurs during an error in cell division leading to cells with an extra set of chromosomes
whats habitat differentiation?
a subset population uses a new component of the habitat leading to reproductive barriers arising - can give differences in resource availabilty
pre-zygotic reproductive barriers
habitat, temporal, behavioural, mechanical, gametic isolation
post-zygotic reproductive barriers
after mating, things that mean fertilised eggs will not lead to viable offspring e.g hybrid breakdown
