LSU Anth 1001 - Tague - Exam 1

Carl von Linne

- wrote Systema Naturae

- advocate of Principle of Fixity of Species

Jean-Baptiste Lamarck

- against Principle of Fixity of Species

- Theory of Inheritance of Acquired Characteristics

Theory of Inheritance of Acquired Characteristics

- organism has needs in order to survival

- needs are met by modification of organs

- continued use of organ leads to increase in size and functional capacity; disuse leads to degeneration

- changes in organ that occur during one's lifetime are inheritable and can be passed to offspring

Georges Cuvier

proposed Theory of Catastrophism

Theory of Catastrophism

- in the past, there were a series of sudden, violent geological and climatic changes that led to the extinction of animals in the affected region

- after the cataclysm subsided, the region was repopulated by animals from neighboring areas that were similar in appearance to those that went extinct

Thomas Malthus

- wrote essay on Principle of Population

Principle of Population

includes a graph on population over time where two lines will intersect where there wont be enough food for our population size

Charles Darwin

- proposed Theory of Natural Selection to explain transformation of a species over time

- observations on Galapagos Islands (finches)

- book On The Origin of Species

Theory of Natural Selection

1. Reproductive potential of a population is great, but actual populations size remains stable

2. Resources in the environment are in a limited supply; there is

competition among individuals for the resources (just restating

Malthus's argument on graph)

3. Biological variation is normal in population

4. Any heredity variation that allows an organism even a slight advantage

in competition for limited resources will be perpetuated, organisms with the favorable variations will survive and produce more offspring, over time there will be an increase in frequency of the favorable traits in the population

1859

On The Origin of Species was published

Alfred Russell Wallace

- same ideas as Darwin; species change by natural selection

Gregor Mendel

- published paper on Inheritance

- pea plants

1866

Mendel's paper on Inheritance

Principle of Segregation

• Genes occur in pairs in an individual organism

• In the production of sex cells, that pair of genes is separated

• Each sex cell contains one of the genes (one of the pair)

Gene

segment of DNA that codes for a protein

Allele

alternate forms of the same gene (ie: round and wrinkled textures)

Genotype

the set of genes possessed by an individual

Phenotype

physical expression of the genotype (what you see)

Homozygous

having 2 copies of the same allele (RR or ww)

Heterozygous

having 1 copy each of different alleles (Rw)

Dominant allele

an allele that is expressed phenotypically in both a

homozygote and a heterozygote

Recessive allele

an allele that is expressed phenotypically in only the homozygote

Punnett square

a way to identify all possibilities when you combine

things

Principle of Independent Assortment

The segregation of one gene does not influence the segregation of other genes (like round/wrinkled and stem length)

Genetic variability

there would be no natural selection without this

Mitosis

- produces 2 daughter cells (each with the diploid chromosome number) that are genetically identical to each other and the parent cell

Homologous chromosome

chromosomes with the same sequence of genes (each chromosome has the same order of genes on the same spot)

chromatids

identical chromosomes

Centromere

constricted part of a chromosome that holds together 2 chromatids

Diploid

full complement of chromosomes (human # = 46)

Interphase

- chromosomes replicate

- 2 chromatids formed, bound by a centromere

- then we enter mitosis

Prophase

1st stage of mitosis

Metaphase

- Chromosomes align in the middle of the cell independent of each other

- Spindle fibers attach to the centromeres

Anaphase

- centromeres divide

- 2 chromatids now migrate to different ends of cell

Telophase

cell divides (into 2)

Meiosis

- production of sex cells

- 4 daughter cells produced (each with the haploid chromosome number)

- each daughter cell genetically different from each other and the parent cell

Haploid

one half of chromosomal complement (human # = 23)

Interphase I

- chromosomes replicate

- 2 identical chromatids

- then we enter meiosis

Prophase I

- homologous chromosomes align / pair wit each other

- recombination occurs ; one strain on each chromatid crosses over

Metaphase I

- Chromosomes align in center of cell

- Homologous chromosomes remain paired with one another (travel together to the center of cell)

- Non-homologous pairs of chromosomes align independently from one another

Anaphase I

- centromeres DON'T divide

- pulled as unit to the sides of the cell

Telophase I

- cells divide (into 2)

Interphase II and Prophase II

nothing new happening at these stages of meiosis

Metaphase II

- chromosomes align in middle of cell

- Alignment of non-homologous chromosomes is independent of one another

- spindle fibers form

Anaphase II

- centromeres divide releasing 2 strains of a chromosome from one another so they can be pulled to opposite sides of cell

Telophase II

each cell divides, leaving 4 total cells

Synapsis

pairing of homologous chromosomes

Recombination/crossing over

physical exchange of DNA between homologous chromosomes only. (only in meiosis)

DNA

- double helix

- made up of nucleotides, a phosphate group, and a sugar

bases in DNA

Adenine

Cytosine

Guanine

Thymine

semiconservative

replication is ______: each DNA strand acts as a template. (each chromatid consists of one parent and one new strand)

Protein

macromolecule of amino acids that is functional in the body

Amino Acids

- components of a protein

- 20 of them

structure of a gene vs structure of a protein

sequence of nucleotides in a gene determines the sequence of amino acids in a protein

protein synthesis

2 stage process: transcription and translation

Transcription

formation of mRNA

RNA

- where Uracil replaces Thymine

- bonding pairs are A - U and G- C

codon

- Triplet sequence of nucleotides in DNA or mRNA that specifies a particular amino acid

- 64 of them

translation

formation of the protein

tRNA

each carries an amino acid and bonds with a codon of mRNA with its (tRNA's) anticodon

anticodon

triplet sequence of nucleotides that serves to bond a particular tRNA with a particular codon

structural genes

genes that produce proteins for the structures of the body

regulatory genes

genes that controlled the activity of a bunch of structural genes

evolution

Change in allele frequencies (in a population or species) over time

mutation

- the one way to introduce new alleles into a species

- the spread of this over time is by natural selection

- NOT the driving force in the origin of new species ( rate too low)

- those that are recessive will be maintained in a population at a higher frequency compared to mutations that are dominant

- allelic variability: increases within population, increases between populations

point mutation

- a change in one nucleotide.

- occurs as a result of an error in replication of DNA

- change in the amino acid sequence, not the amino acid

Charles Lyell

- proposed Theory of Uniformitarianism

Theory of Uniformitarianism

forces existing today that shape the earth are the same as those that acted in the past

chromosomal mutations

- the position of a gene on a chromosome may be important in its expression

- If the position of a gene is changed, the phenotype may be changed

dosage effect

imbalance in chromosome number

discontinuous traits

- only a FEW distinguishable phenotypes in a population

- traits are NON-polygenic (only based on ONE gene)

- Ex: short/tall and wrinkled/round; nothing in between

continuous

- GREAT VARIETY of phenotypes, where one phenotypic expression flows into another

- traits are POLYGENIC

polygenic

when multiple genes affect a trait, the trait is _______

Formula for calculating number of genotypes for a polygenic trait

(a*(a+1)/2)^G

- a = # of alleles of a gene

- G = # of genes

Heritability of Traits

G = genetic, E = environment, P = phenotype

- P=G+E

- VP = VG + VE

- P=G/P+E/P

_______ index = VG/VP = G/P

The effectiveness of natural selection in causing evolution is directly related to this

gene pool

The total store of genes and their alleles in a population

population

Community of individuals within which matings occura

allele frequency

The proportion of an allele relative to all alleles for a particular gene

Conditions of Hardy-Weinberg Theorem

1. Random mating

2. Infinitely large population size

3. No natural selection

4. No mutation

5. There is no migration

Hardy-Weinberg Theorem

There is no change in allele frequencies and genotype frequencies in a population over time if certain assumptions (or conditions) are met

Inbreeding

- aka positive assorting mating

- matings between individuals of similar phenotypes and genotypes

- genotype frequency: INncrease in HOMOzygosity, DEcrease in HETEROzygosity

- NO change in allele frequency

outbreeding

- aka negative assorting mating

- matings between individuals that aren't related

- genotype frequency: DEcrease in HOMOzygosity, INcrease in HETEROzygosity

- NO change in allele frequency

gene flow

- The exchange of alleles between populations; interpopulational matings

- inhibits speciation

- allelic variability: Increases within population; Decreases between populations

species

group of interbreeding organisms that are reproductively isolated from other such groups

speciation

- Results when one population of a species can no longer

interbreed with other populations

- This reproductive isolation occurs when one population (A) becomes geographically isolated from the other populations (B-D)

- There is a build up of gene pool differences between population A and populations B-D

- If these differences preclude interbreeding between population A and B-D, then a new species has arisen

(Gene pools isolated from one another)

genetic drift

- evolution due to random factors

- magnitude of evolution by this is inversely related to population size

- every pop. evolves every gen. by this

- allelic variability: decreases within pop, increases between pops

fixation

the frequency for one allele is 1.00, and all other

alleles for that gene are lost from the gene pool

factor effect

change in allele frequencies due to a sudden reduction in population size

Natural Selection

1. The individual organism is the unit of natural selection. The population is the unit of evolution.

2. The ability of natural selection to cause evolution is directly related to the heritability of traits

3. Adaptation is the result of natural selection

4. Fundamental Theorem of Natural Selection - The opportunity for natural selection to occur is directly related to the genetic variation in the population

5. Natural selection is opportunistic (doesn't create new structures, acts on what's already there)

gradualism

- evolution is a continuous process

- Ex: pop A becomes isolated from B-D -> gene pools diverge by natural selection -> pop A becomes reproductively isolated from B-D -> new species has emerged

punctuated equlibrium

- evolution is a discontinuous process

- involves period of rapid speciation followed by long periods of stasis

- Ex: pop A becomes isolated from B-D -> gene pools diverge by random forces of mutation -> pop A becomes reproductively isolated from B-D -> new species has emerged

fossil record gaps

- Gradualism = low probability of finding them because of imperfections in fossilization process

- Punctuated equilibrium = gaps represent that speciation occurs in short period of time in small number of individuals; small probability of finding those transitional species