Biology

- Evolution Explains life unity and diversity - Natural selection is a cause of adaptive evolution

-Linnaeus -Hutton & Lyell-Malthus-Cuvier-Lamarck-Mendel-Wallace

Classification

Geological Change

Population growth resources

Fossils and extinction

Species Change

Inheritance patterns

Evolution & Natural selection

"Descent with Modification"

A type of logic in which generalizations are based on a large number of specific observations

A type of logic in which specific results are predicted from a general premise.

He made three basic inferences based on five observations.

-Population sizes would increase if everything survived. -Populations tend to be stable in size except in seasonal fluctuation -Resources are limited-Much variation is heritable

-When more individuals than environment can support leads to a struggle for existence-Survival depends in part on inherited traits-Over many generations this unequal survival will yield changes in the population

The change in genetic properties of populations over generations.

-Artificial selection-Direct Observations in the wild -Homology-Fossil Record-Biogeography

Study of patterns of distrubution of animals

Evolution

natural selection

-1822-1884-Did experiments on pea plants to determine patterns of inheritance-He did NOT know about DNA

A strand of DNA

Diploid organisms

A specific place on a chromosome that codes for a specific trait

-An alternate form of a gene-Dominant masks recessive in phenotype

A discreet hereditary unit found in DNA

An individuals genetic composition

A visible characteristic of an individual it is also an interaction of genotype and environment.

-Why there is so much variation in populations-Future characteristics of population

All alleles together in a population (May be 1, 2, 3, or many many more.) NOTE: Individuals only have TWO alleles.

Group of individuals of the same species that live in the same area and interbreed, producing fertile offspring.

p+q = 1- where p = Frequency of Dominate allele and q = frequency of recessive allele

YES!

Using the Hardy-Weinberg Equation

A principle that states that the frequencies of alleles and genotypes in a population will remain constant from generation to generation, provided that only Mendelian segregation and recombination of alleles are at work.

A gene pool where the only forces at work are mendelian segregation and recombination of alleles.

p^2 + 2pq + q^2 = 1

• p=expected frequency of genotype C^RC^R
• pq= expected frequency of genotype C^RC^W
• q=expected frequency of genotype C^WC^W

Examining allele and genotype frequencies in populations

q*q

p*p

2*p*q

• 1.) No mutations
• 2.) Random Mating (NO preferentioal mating)
• 3.) No natural selection
• 4.) Extremely large population size
• 5.) NO gene flow

• *Due to accidents in DNA.
• * Happen ALL the time, but slowly
• * Sorce of all genetic variation
• * Required for evolution

• * Males often compete for territories or mates
• * Competition occurs through ornamentation, vocalization, fighting, etc.
• *Female choice plays a roll
• * Female choice ex: = lekking behavior

When males congregate and do their display and then the females choose the mate. Generally one or few males do ALL of the mating.

Migration changes allele frequencies! Migration is generally always occuring.

ALL populations are finite. Moreover, populations risk genetic drift and sample error. Both of those are more likely to happen in smaller populations.

• * Population bottle neck
• * Founder Effect

• An example of genetic drift. This takes place when a population crashes, and a once rare allele becomes a prominant / common allele. These can be as small as one generation.
• EX: Elephants and cheetahs both had this occur to them and now they have low genetic variation and great problems with converation because of this.

• An example of genetic drift.
• When a few individuals leave a group and start a new population. Once rare alleles can become very common alleles in the new population.
• EX: Omish community that inbread and often have 6 fingers.

Adaptation always occurs. Traits favoring survival and reproduction will outlive those that don't.

• *More individuals are produced than survive due to competition for limited resources
• * Individuals vary within populatinos
• *Some variants have more offspring
• *Individuals with favorable traits reproduce / survival of the fittest

The ability to pass along many copies of your genes onto the next generation.

Phenotypes!

Natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than do other individuals.

EX: White polar bears VS black polar bears

Natural selection in which intermediate phenotypes survive or reproduce more successfully than do extreme phenotypes. Likely in a stable envioronment. Variance in phenotypes reduced.

Natural selection which favors extreme phenotypes. Variance increases. Possible in variable or patchy environments.

A trait that enhances fitness. Depends on many environmental factors and depends on other genes.

Natural selection in which both inter and intrasexual selection. Differential reproduction due to variation in ability to obtain mates. May lead to trade off.

• Increase fitness via sexual selection
• decrease selection via other natural selection

NO. Drift and mutation are random. They MAY encounter NS but not necessarily.

Mindless.

• *Adaptation is a comprimise, different selective forces at one time. Selective forces change over time
• * Not all evolution is adaptive. (drift and mutation)
• * Historical Constraints (Starting materials for a pop)
• * Not enough variation (This doesn't allow for change!)

Heterozygotes!

• They are the most fit because they have the most variance.
• Ex: sickle cell animia : aa = anemic but Aa = malaria resistant . . . Aa is not infected but IS a carrier, keeping the sickle cell population allive and viable to be passed down

• * Rare individuals may survive parasites
• * Predators search out similar traits each time (if you're different - wa la)

Selective forces change over time.

Sometimes a variation doesn't do anything, but over time it very well may as the environment changes or a new predator shows up, etc.

Usually within a single species within a population where you see a casual change as you move across the population.

One population varying greatly among another population of the same species. (What we normally talk about in bio)

Speciation occuring in populations that live in the same geographic area.

Gene flow is interrupted when a population is divided into geopgraphically isolated subpopulations.

• *Sympatry
• *Successful interbreeding