Evolution 2 Flashcards
What does “neo-Darwinism” mean?
It was coined to reflect the understanding of natural selection + genetic basis of inheritance in the 1930’s and 40’s
What is another term for Neo-Darwinism?
Modern sythesis
What was the largest leap in biological understanding after the 1940’s?
Understanding the structure of DNA
What is evolution within a species called?
Micro-evolution
What does Micro-evolution involve?
The change in frequencies of alleles in a population between generations
What is a population?
A localized group f individuals of the same species
True or false:
Much like a population, a single individual can evolve
False:
A population can evolve (microevolution) but individuals cannot evolve
What are the five main factors that can alter the frequencies of alleles within a population?
1: mutation
2: natural selection
3: Genetic Drift
4: Gene flow
5: Extinction
What is a mutation?
A change in an individual’s DNA
What can cause a mutation ?
- error in DNA replication
- Structural damage of DNA
What happens when their is a mutation in the DNA of a creatures Gametes?
Then the mutation will be passed on to its offspring
Can single celled organisms avoid passing on their mutations?
No, they have no gametes, thus when there is a mutation it is wholly passed on through the process of self replication
True or False:
Mutations can happen randomly or in response to particular selective factors
False:
Mutations only happen randomly, the results of the mutations can be positive, negative, or null
Why are genetic mutations important?
Because it allows for evolution through genetic diversity
Are neutral mutations always silent?
No,
If the environment changes it can cause the neutral mutation to surface either positively or negatively
What are micro-mutations?
Mutation that only have small changes on the organism.
What are Macro-mutations?
Mutations that have a large effect on the organism.
Are the majority of mutations macro or micro?
Micro-mutations
How do most Macro-mutations occur?
through the mutation of a that gene that controls the development of a certain aspect.
What mode of evolution results in adaptations?
natural selection.
What is an adaptation?
An adaptation is a feature, created through the process of natural selection, that provide an advantage to an individual possessing it.
natural selection acts on a __-_______ variation
Pre-existing
What is the origin of heritable variability?
Mutation
How can natural selection affect distribution of allele frequencies?
1: directional selection
2: Diversifying selection
3: Stabilizing selection.
What is directional selection?
When the mean of the original population shifts as a whole, losing some species but maintaining its shape.
- the mean changes
What is diversification selection?
The center of the bell curve shrinks and the two ends rise up.
The mean of the population becomes split, the variance increases.
What is stabilizing selection?
When the variance of a species decreases and the mean of the graph increases in height.
Is survival of the fittest am accurate phrase?
No, you do not have to have greater fitness than the rest. Only a greater reproductive success.
What is the definition of fitness in a biological prospective?
The ability to produce offspring that themselves survive to reproduce
What are the two main types of selection?
Sexual and natural selection.
What are the two main types of sexual selection?
Intra-sexual
Inter-sexual
What is intra-sexual selection?
The competition between the same sex for assess to mates.
What is an example of Intra-sexual competition?
Male deer growing larger and sharper antlers to fence with other deer looking to take their mates.
Sexual selection result:
Larger antlers
What is inter-sexual selection?
The selection of traits based off of the interaction between the sexes
What is a example of inter-sexual interaction?
Male jumping spiders will grow colorful hairs across their body to impress a female.
Sexual selection:
Females mate with brightly colored males, thus they will evolve brighter colored hairs.
Why did Darwin separate natural and sexual selection?
Because it seemed like some sexually selected traits would act against selected ones.
ie: peacock feathers make them an easy target, but it was evolved as a sexually selected trait.
What do biologist conciser sexual selection to be today?
A simple category within natural selection
What is genetic drift?
The change in a populations allele frequency through chance rather than selection.
What can cause genetic drift?
Small, random fluctuations in reproductive success.
- Bottle neck
- Founder Drift
What is an example of genetic drift?
you have 100 marbles in a bag: 50 red/ 50 blue.
You randomly take out 50.
You now have 20 red / 30 blue.
The genetic frequency is not deceased for the red allele
What is a genetic Bottle neck?
It is a dramatic reduction in genetic diversity, due to a massive drop in population size, and drop in allele diversity.
What is the founders effect?
When a small number of individuals without full complement of allele diversity start a new population in a new area.
What size of population is most greatly affected by founders effect/genetic drift?
Small populations
What is gene flow?
The occurrence of when individuals interbreed or migrate among populations.
What effect does gene flow have on genetic drift?
It counteracts it
What effect does Gene flow have on Adaptation and diversity?
- slows local adaptation
- reduces phenotype diversity
What is extinction?
The complete loss of a portion of a species diversity.
What is local extinction called?
Extirpation
Evolution at the population level is often called what?
Micro evolution
How does micro evolution occur mainly?
Through selection
Evolution at a species/clade level is called what?
macroevolution
What is a species based off a taxonomist definition?
What a taxonomist says it is
What is a species from a biologist perspective?
Population or group of populations whose individuals are capable of interbreeding and producing viable fertile offspring.
What is wrong with the biological definition of a species
does not work for asexual organisms or plants
What is DNA bar coding?
An attempt to use molecular methods to recognize and discover species.
What is the benefit to DNA bar code?
There is little variation within species, and clear differences between species.
What is the common use of the DNA Barcode?
it is used to identify already described
species
And within Wildlife forensics
What is speciation?
we observe that Cohesive units of morphologically and behaviorally similar organisms exist, regardless of definition.
How did Darwin argue species arose?
Gradually through previously existing species, an believed that natural selection was the primary driver.
What are the two theories of speciation as seen through the fossil record?
Anagenesis
Caldogensis
What is Anagenesis
Refers to gradual transformations of one species into another
and
gradual change within a lineage that does not involve sepaciation
What is Cladoegensis?
Refers to splitting of ancestral species into two or more species
What is gradualism?
Slow differentiation by natural selection over many generations
In the 1970’s Gradualism challenged what idea?
It challenged the idea of punctuated equilibrium
What is punctuated equilibrium?
Speciation that happens rapidly, followed by relitive long period of stasis
What are the two main ways that a species can be reproductively isolated?
( no longer can mate with original species)
1: Prezygotic behavior prevent sperm from meeting the egg.
2: Postzygotic barriers act after egg and sperm got together.
What are the five main factors that play into Prezyotic barriers?
speciation
1: Habitat
- one in medow, other in forest
2: Timing
- They reach sexual maturity at different ages
3: Behavior
mating calls are different
4: Mechanical
Genitals or body size are different
5: Gametic
The eggs or sperm cannot recognize each other
What are the main factors that play into Postzygotic barriers?
speciation
- hybrid offspring of A and B may die
- Hybrid offspring of A and B may be infertile
- Hybrid offspring may be unable to produce viable offspring
What is speciation via hybridization?
Hybrids of A and B may be fertile among themselves, but reproductively isolated from parents
Where is hybridization most commonly found?
Plants
What is polyploidy in plants?
Mutations within seed may lead the play to be self compatible, but isolated from parents
Where is the evidence of specication?
Fossil records, geographical differentiation, and lab experiments in mating preferences.
True or false:
Micro and Macro evolution have stopped occurring due to human interaction with the environment
False.
Micro and Macro evolution are still very much happening today.
