biological population
Groups of individuals of the same species
- Somewhat independent of other groups
- Often isolated by geography
Evolution
Change in the characteristics of a population of organisms that occurs over the course of generations
-Inherited via genes
natural selection
Process by which populations adapt to their changing environment
Microevolution
Changes that occur within a biological population
- Easily observed
- Noncontroversial
Macroevolution
Large-scale evolutionary changes that result in the origin of new species
- Occurs slowly over long periods of time
- Controversial among non-biologists
Darwinism
term often applied to the theory of evolution
Darwin's discovery for two important and unexpected patterns:
1. Traits exhibited by species
2. Similarity between the fossils of extinct species and the living species in that same area
mutation
An alteration of the base-pair sequence of an individual's DNA
Fixation
...
allele
a particular version of a gene
allele frequency
how often a form of a gene appears in a gene pool
Founder effect
A small number of individuals may leave a population and become the founding members of a new, isolated population.
gene flow
movement of alleles from one population to another
"put one person from one place to another
bottleneck
Because the population is reduced to a small fraction of its original size
"population reduces
migration
long distance movement.... The third agent of evolutionary change
Theory of natural selection
The physical or behavioral traits of organisms that lead to increased survival or reproduction become more common in a population.
- Most important cause of evolution
Darwin's observations
1. Individuals within populations vary.
2. Some of the variation among individuals can be passed on to their offspring.
3. Populations of organisms produce more offspring than will survive.
4. Survival and reproduction are not random.
Darwin's inference
Natural selection causes evolution.
The modern synthesis
the union between genetics and evolution; predicated on genetic principles
Directional selection
Changes in a population in a particular direction.
it has completely shifted to one direction. one extreme is disadvantage and one is better.
Stabilizing selection
Population stabilizes; changes are resisted.
stays the same
Diversifying/Disruptive selection
Changes in a population result in two or more variants
biggest gap
Will people have to die first so we can be resistant to stuff like Tb, hiv?
Yes, true
Sexual selection
when a trait influences the likelihood of mating
Assortative mating
preference to mate with someone like self
which example describes biological evolution
Over time, a caterpillar species becomes as green as the leaves it eats
Which two observations led Darwin to conclude that there is competition for survival?
overproduction and limited resources
what molecule does a sequence of DNA typically code for
protein
Why or why is it not accurate to say that individuals evolve?
it is not accurate because individuals do not change over time in a way that can be passed on the next generatioin
Why is it inaccurate to say that humans are the most highly evolved species?
all species not just people are equally "evolved" to fit their particular environment
evolution is not goal oriented. it only acts in response to present situation
both of these are correct
A zombie apocalypse wipes out almost the entire human species before the zombie threat is eliminated. Only a group of 100 people who were at a family reunion on an uninhabited island survived. They returned to the mainland completely unaware of what had h
bottleneck effect
what does it mean to be survival of the fittest?
...
a straggler with green eyes stumbles into the last remaining human outpost. The green eye trait did not exist in the outpost before her arrival, but it does now. What is the name of this mechanism of evolution?
gene flow
What does "fitness" mean when speaking in terms of evolution?
how many offspring an individual produces
reproduction
After a rapid change in climate, one population of bird quickly adapts to the change, but others in the area do not. What could you conclude about the quickly adapting population?
they already had some alleles in their genome that were adaptive in the new environment
"their genes may went thru this b4
Which variation could be subject to natural selection?
a hyena is born with spotted fur pattern that allows it to hide in the grass better than its littermates
A trait that confers (grants) ________ in one environment might make an organism less able to
survive and reproduce
in another environment.
fitness
As natural selection acts on a trait in a population,how will the amount of variation associated with that trait in the population change?
variation will decrease
What type of selection would include the evolution of a long neck in giraffes?
directional selection
which example is an evolutionary adaptation?
webbed feet on a bird
In what way is artificial selection different from natural selection?
in artificial selection, human preference is the selecting force; in natural selection environmental conditions are selecting the fore
you notice that some squirrels in your neighborhood have a much darker coat color than most of the other squirrels. Is this darker color an adaptation?
the trait is only an adaptation if it gives the squirrels an advantage in their habitat