Topic Test 1 Flashcards
What is a trait
an observable characteristic
What is a phenotype
what value of a trait is observed
What is a quantitative trait
traits where phenotype can be measured on a continuous scale
What is a qualitative trait
traits where the phenotype is measured on a categorical scale
What are morphological traits
traits where the phenotype has to do with the shape, structure, colour, pattern, or size of an individual or species
What are behavioural traits
traits where the phenotype has to do with the behaviour of an individual/species
What are life history traits
traits related to the timing of development and reproduction; longevity, size/number of offspring
What are the two variations of traits
heritable and non-genetic
What is heritability
a measure of how important genetics are to determining a trait
What is phenotypic plasticity
when the exact same genotype produces different phenotypes in the environment
What is sexual dimorphism
traits that vary between biological sexes in a species (usually specific to certain traits)
What type of species is sexual dimorphism relevant to
dioecious species
What is a dioecious species
species that have separate males and females
What does biodiversity typically refer to
the total number of different species
Scientific research usually has a __________ and __________ team, but focuses on a _____________ question or concept
big and diverse team
specific concept or question
Biological traits are ______________ characteristics of an individual
observable
What are the different ways traits can vary
heritability, plasticity, and whether they are sexually dimorphic
What is evolution
the process that results in changes in the proportion of heritable traits within populations from one generation to the next
What are the 4 mechanisms/forces that drive evolutionary changes
- natural selection
- mutation
- genetic drift
- gene flow
What is the only mechanism of evolution that leads to adaptations
natural selection
Natural selection is the only mechanism of evolution that leads to…
adaptation
What are adaptations in terms of evolution
traits that provide a “fit” between an organism and its environment
What are Darwins 3 postulates
- phenotypic variation exists within a population
- differential reproduction/survival occurs based on that phenotypic variation
- this variation is genetically heritable
If Darwins 3 postulates are true, what is occurring
natural selection
Do populations adapt because they “need” to?
no
Why don’t populations adapt due to needs
natural selection lags behind environmental change
What quality do the “fittest” organisms have
most successful at passing on their genes
What is fitness a measure of
how many successful offspring an organism creates (NOT a measure of traits like speed or strength)
Traits that increase reproduction are ________________
adaptive
What is directional selection
when the variation moves up or down the scale but distribution remains constant (ie. beak size average increases by 10%, but the distribution remains, just moves up on the graph)
What is stabilizing selection
when the genetic variants lead to extremes (ie. smallest and largest in the distribution become closer to the average, creating a steeper peak and shorter distribution)
What is disruptive selection
genetic variants lead to average becoming less common than ends of the spectrum
Is evolution synonymous with natural selection?
no
Are mutations random or directed
random
What is the form of selection when it shifts in one direction
directional
What is the form of selection when variation is reduced
stabilizing
What is the form of selection when it favours the extreme values and average is reduced
disruptive
What does it mean for natural selection to “not be directional”
what is adaptive now is not necessarily adaptive tomorrow, it changes
What would cause rates of natural selection to increase
high natural pressures
What is a gene
a sequence of DNA that encodes for a functional product
What are alleles
different versions of info that could be encoded for a given gene
Do most mutations lead to new phenotype
no
In order for mutations to influence evolution where must they occur
in gametes (sex cells)
What is genetic drift
change in allelic frequencies that happen through random chance
When is genetic drift occurring
always!
What populations are affected more by genetic drift; small or large
small (think in terms of probability)
What is gene flow
the flow of individuals of the same species from one population to another
What is speciation
when individuals from a species diverge and isolate, and develop unique features that the original population doesn’t have
Speciation requires ____________ __________
gene flow
Evolution can be understood as _________ frequencies over time
allelic
What is the purpose of a phylogenetic tree
depict evolutionary relationships between different taxa
When are species the most commonly related
when they have a more recent common ancestor
What is a clade
monophyletic: common ancestor and all of its descendants (think about making a cut on the tree, everything that comes off is a clade)
What is meant by paraphyletic
common ancestor and a subset of its descendants (but not all)
What is meant by polyphyletic
two species that share a trait because of convergent evolution
What is shared ancestry
traits shown by different individuals as a result of inheritance (the trait is SHARED)
What is convergent ancestry
traits shown by different individuals as a result of random inheritance (not directly related on the tree)
Convergent evolution is also called…
homoplasy
What is homoplasy
convergent ancestry: common traits not by direct inheritance
What is homology
shared ancestry: common traits inherited
What is parsimony
the most likely set up of a phylogenetic tree
What is a species
a group of individuals that actually or potentially inbreed in nature
biological species concept
What is the biological species concept
“a group of individuals that actually or potentially inbreed in nature” in terms of what is a species
What does the morphological species concept define species by
physical characteristics
What does the ecological species concept define species by
ecological roles and interactions
What does the phylogenetic species concept define species by
evolutionary relationships and genetic data
What does the genotypic cluster concept define species by
uses genetic data to identify distinct clusters of individuals
Speciation requires…
reproductive isolation
What is allopatric speciation
species splits due to geographical barrier
What is sympatric speciation
species splits by reproductive separation even though they are in the same place
