Introductory Biology II concept Map

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Introductory Biology II concept Map

Population Regulation

What we do to control the population ourselves:

Smoking

Obesity

Alcohol Use

Automobile accidents

Suicides

AIDS

Homicides

War

Key:

Red: Exam 1

Yellow: Exam 2

Blue: Exam 3

I expanded the most on the areas I needed the most review.

Dieases help contrrol our population growth

Measles

Tuberculosis

Small Pox

Flu

Resources are limited and limiting on population growth.

Food

Water

Air Quality

Lliving Space

Biological Control of Pests:

Hormonal control

Pheromone stations

Pheromone traps

Reproductive control

Release Sterile males

Chemical Sterilants

Release incompatible pest stains

Control by another organism

Parasites

Predators

Pathogens

Population Growth

A population is a group of interbreeding individuals of the same species in a particular site.

Steady population growth depends on a balance between growth factors and environmental resistance factors like:

Unsuitable or destroyed habitat (-)

Adequate Food Supply (+)

Specialized Niche(-)

Generalized Niche (+)

Low reproductive rate (-)

High reproductive Rate (+)

The environment (including other species present therefore competition)plays a major role in the growth of a population.

Competitive Exclusion Principle: When similiar species that compete for the same limiting resources cannot coexist in the same environment (if their niches are identical.) One will use the resources more efficiently and thus reproduce more rapidly. Even a slight reproductive advantage will eventually lead to local elimination of the inferior competitor.

OR a species can evolve through natural selction to use a different set of resources/niche to avoid competition and coexist. (each species K value is lower)

The Logistic growth of a population is s-shape and takes into account how many individuals of the same species can be supported by the environment (carrying capacity (k).)

Not all species have the same carrying capacity because every species interacts with the environment in a different way.

Adaptive Radiation

Adaptive Radiation is the development of several new species from a common ancestor due to adaptations to different environments.

Remember that all species arise from preexisting species.

Adaptive radiation is pretty similiar to divergent evolution the only difference is that the radiation happens all at the same time.

Contemporary Extinction:

Habitat Destruction

Overgrazing

Farming

Deforestation

Hunting

Over exploitation

Species Introductions

Introduces new diseases

Increase Predation

Increase Competition

Hybridization

Inbreeding

Speciation

Species are groups of (reproductively isolated) actually or potentially interbreeding (therefore gene flow occurs) populations.

As divergent evolution occurs (the accumulation of phenotypic differences between 2 lineages originating from a common ancestor over time) the two lineages eventually become different species that are unable to exchange genes.

Divergent Evolution occurs with character displacement over time.

Character displacement refers to the phenomenon where differences amoung similiar species whose distributions overlap geographicallyare accentuated in regions where the species co-occur to reduce competition.

However, Sometimes (1% of the time) two species are able to mate and produce a hybrid species.

This can create a hybrid that is considered Polyploidy.

Can also be cause by a nondisjunction of chromosomes of one parents chromosome in their gamete thereby producing a polyploidy when combined with a normal gamete.

Can be caused by an unreduced gamete and a normal gamete coming together to form a triploid gamete or a new species.

Allopatric Speciation: species formation from a common ancestor in geographically separate locations (therefore it occurs in isolation.)

Migration

Migration is the movement of genes between populations.

Migration tends to eliminate existing genetic differences between populations.

Allele frequencies change in the direction of the donor /source population due to migration.

Hardy Weinburg Equation cannot be used to calculate the allele or genotype frequencies if this occurs.

Migration Rate: the proportion of immigrants in a population after migration.

Therefore: Migration rate is the number of immigrants divided by the new total population.

If we know the migration rate, we can find out migration rate of alleles.

Q(after immigration)= q ((the recessive allele frequency)of immigrants) M(migration rate)+q (residents)

To find P just subtract the new q value from 1.

Because p+q=1

Mutation and Genetic Drift

Genetic Drift is the random changes/ deviations in allele frequncies in a population from generation to generation.

Can be a result of the genetic bottleneck effect.

Genetic Bottleneck Effect: Random changes in allele frequencies in a population due to a dramatic reduction in population size.

A result of sampling error in a population of limited size.

Sampling error is the random deviation from the expected value determined by chance

Therefore, the larger the population/ sample size the smaller the deviation on average.

Genetic drift involves colonization thus creating the founder effect.

Founder Effect: Random changes in allele frequencies in a population during colonization.

It's basically the colonizer's chance of deviation from the gene frequencies of their source population.

A mutation is a random change in the genetic code.

Every locus has a different mutation rate.

Mutations are where new alleles come from

Mutations are the ultimate source of genetic variation.

Mutations are considered good or bad based on their environment.

Selection

Natural Selection operates in human populations to ensure the reduced survival and minimal reproductive potential of inferior species.

ensures minimal reproductive potential by making most mutants infertile or sterile. So only the superior/most able-bodied species survive.

Selection Differential: The difference between the mean of the population and the mean of individuals selected to be the parents of the next generation.

Therefore: Selection Differential= Mean(selected)-Mean (whole)= Mean intensity of selection.

Selection as defined by Dr. Levin: Differential reproduction amoung differing phenotypes in a population.

Selection is basically the only form that produces adaptive evolutionary changes for a population. It is the only way for a populaiton to improve.

There are many different kinds of selction.

Artificial Selection: Modification of a species by human intervention so that certain desirable traits are represented in successive generations.

Influenced by the heritability of the trait and the pressure/ force that the breeder uses.

Stabilizing Selection: Genetic diversity decreases as the population stabilizes on a particular trait, the intermediate is favored.

Disruptive Selection: changes in population genetics in which extreme values for a trait are favored over intermediate values.

Directional Selection: When a single phenotype is favored causing allele frequency to continually shift in one direction.

Environmentally Dependent

The Chromosome Complement

Chromosomes are the visible bodies within dividing cells that contain DNA and thus carry genetic information.

Humans are diploid, meaning we have 2 sets (2n) of chromosomes therefore, 23 pairs of chomosomes.

We get one chromosome set from each of our parents.

This is made possible through Meiosis which is a 2 stage type of cell division in sexually reproducing cells that results in half the chromosome number than the parent.

Sometimes there are alterations in the chromosome number that cause genetic disorders like Down Syndrome (trisomy 21.)

Meitoic disjunction is when members of a pair of homologous chromosomes do not separate during Meiosis I or sister chromatids fail to separate during meiosis II.

Creates Monomy

Creates Trisomy

Dihybrid Cross: crosses between 2 loci that are both heterozygous.

Monozygotic Twins: Share 100% of their genes.

Dizygotic twins: share 50% of their genes.

Monohybrid cross: crosses between genotypes with one locus that are heter- ozygous.

Both crosses give rise to a charactersitic or phenotype

Quantitative traits: refer to the phenotypes that vary in degree because of polygenic effects ans their environment. Theycan be measured like body weight, IQ etc.

Therefore, genotype and the environment effect phenotype.

The heritability of a trait is the proportion of the phenotypic variation that is genetically based. (range values: 0-1)

1: All differences are genetically controlled.

0: All differences are environmentally controlled.

Meiosis guarantees the continuity of genetic information from one generation to another.

Additionally, humans have 2 sex chromosomes

Male: XY

Female: XX