PP1-3

Cell

smallmembrane-enclosedFilled with a concentrated aqueous solution of chemicalsEndowed with the ability to create copies of themselves

mutation and natural selection

Gives them new ways to exploit their environment more effectivelySurvive in competition with others.Reproduce successfully

unity

All life displays a common set of characteristicsUnited by a shared evolutionary history

diversity

Life has a diversity of forms in diverse environments

evolutionary history

understand the structure and function of an organism

atoms; molecules and macromolecules; cells; tissues; organs; organisms; populations; community; ecosystem; biosphere

Vertical descent w/ modification

Progression of changes in a lineageNew species evolve from pre-existing species by the accumulation of mutationsNatural selection takes advantage of beneficial mutations

horizontal gene transfer

Genetic exchange between different speciesRelatively rareGenes that confer antibiotic resistance are sometimes transferred between different bacterial species

taxonomy

grouping of species based on common ancestry

three domains of life

Bacteria, unicellular prokaryoteArchaea, unicellular prokaryoteEukarya, unicellular and multicellular eukaryotes

eukarya

complex cells w a nucleus

four kingdoms of eukarya

protista, plantae, fungi, animalia

domain, kingdom, phylum, class, order, family, genus, species

genome

the complete genetic makeup of an orgnanism

genomics

technique used to analyze DNA sequencescomparison of genomes of different species

proteome

the complete complment of proteins of an organism

proteomics

techniques used to analyze the proteins of a speciescomparison of proteomes of different species

genome;proteome

The _________ carries the information to make the ____________

genomic and proteome analysis illuminate the__________ ___________ and relatedness of all living organisms

evolutionary history

asexual reproduction

produces genetically identical copies  (clones)

sexual reproduction

introduces variation in the combinations of traits among offspring

homologues

autosomes that are the same size and structure

sex chromosomes

one pair of chromosomes (x and y)

genes

regions in an organisms DNA that encode information about heritable traits

alleles

different forms of the same gene

diploid cell

two nonidentical copies of every chromosome (except XY sex chromosomes)

1 interphase

Chromosomes have already been replicated.

2 prophase

Sister chromatids condense, and the mitotic spindle starts to form.The nuclear envelope begins to dissociate into vesicles.Nucleolus is no longer visible.

3 prometaphase

The nuclear envelope has completely dissociated into vesicles, and the mitotic spindle is fully formed. Sister chromatids attach to the spindle via kinetochore microtubules.

4 metaphase

Sister chromatids align along the metaphase plate.

5 anaphase

Sister chromatids separate, and individual chromosomes move toward the poles as kinetochore microtubules shorten. Polar microtubules lengthen and push the poles apart.

6 telophase and cytokenesis

Chromosomes decondense, and the nuclear envelope re-forms. Cytokinesis separates the mother cell into two daughter cells, which begins with a cleavage furrow in animal cells.

haploid gametes

meiosis in germ cells ½ the diploid # of chromosomes (2n) to haploid number (n) final product is reduction division

nondisjunction

Chromosomes do not sort properly during cell divisionDuring meiosis can produce aneuploid gametes (too many or too few chromosomes)

euploid

normal # of chromosomes

polyploid

3 or more sets of chromosomes

aneuploidy

abnormal # of particular chromosome

trisomic (aneuploidy)

2 normal copies + a 3rd2n+1

monosomic (aneuploidy)

missing 1 normal copy of chromosome2n-1

meiosis I

Duplicated homologous chromosome is separated from its partner

meiosis II

sister chromatids are separated

mutations

original source of genetic diversity

genetic variation

reshuffling of alleles during sexual reproduction produces ____ _____independent assortment of chromosomescrossing overrandom fertilization

n=23 humans

Homologous pairs of chromosomes orient randomly at metaphase I of meiosis

crossing over

produces recombinant chromosomes, which combine DNA inherited from each parentbegins very early in prophase I, as homologous chromosomes pair up gene by genehomologous portions of two non-sister chromatids trade placescontributes to genetic variation by combining DNA from two parents into a single chromosome

prophase I

Chromosomes begin to condenseIn synapsis, homologous chromosomes loosely pair up, aligned gene by gene

Chiasma

the points at which members of a chromosome pair are in contact during the prophase of meiosis

prophase Ianaphase Ianaphase IIdaughter cells

random fertilization

adds to genetic variation because any sperm can fuse with any ovum (unfertilized egg)Each zygote has a unique genetic identity

Mendel

pea plant

genotype ratio

TT:Tt:tt1:2:1

phenotype ratio

tall:dwarf3:1

Dihybrid offspring

offspring are hybrids with respect to both traits

Probabibility

the chance that an event will have a particular outcomeP = # of times an event occurs / total # of possible outcomes

probability that 2 or more independent events will occur is = to the product of their individual probabilities

½ x ½ = ¼

the sum ruleThe probability that one of two or more mutually exclusive outcomes will occur is the sum of the probabilities of the possible outcomes

¼ + ¼ = ½

The Relation Between Dominance and Phenotype

A dominant allele does not subdue a recessive allele; alleles don’t interactAlleles are simply variations in a gene’s nucleotide sequenceFor any character, dominance/recessiveness relationships of alleles depend on the level at which we examine the phenotype

incomplete dominance

heterozygote shows intermediate phenotypeneither allele is dominant

codminance

multiple alleles: 3 or more variants in a populationphenotype depends on which 2 alleles are inherited

epistasis

Alleles of one gene mask the expression of the alleles of another geneOften arises because two or more different proteins are involved in a single cellular function

Quantitative characters

vary in the population along a continuum

polygenic inheritance

addictive effect of 2 or more genes on a single phenotype

polygenic inheritance example

skin color in humans

_____ provides the plan to create a _____. the _________ provides nutrients and energy to carry out the plan

genotype; phenotype; environment

norm of reaction

effects of environmental variation on a phenotype

karotype

pedigree analysis

dominant alleles

some human disorders are caused by

rare; mutation

dominant alleles that cause a lethal disease are ____ and arise by _____

sex-linked gene

a gene located on either sex chromosomehumans: refers to gene on the larger X chromosomeMales are hemizygous for X-linked genes

SRY gene lies on the Y chromosome

sex-linked gene

_____ ____ (__) encodes defective versions of a clotting protein

disease allele (X^h-A)

X inactivation

One X chromosome in the somatic cells of female mammals is inactivated

2 lines of evidence for X inactivation

Barr bodies are found in female but not male cat cellscalico cat coat color pattern

X chromosomes

extra _-_____ are converted to Barr bodies

Cell counts based on # of X inactivation centers (Xic) containing the ____ gene

Xist

initiation and spreading

occur only during embryonic development

Mosaic

female mammals heterozygous for X-linked genes have half their somatic cells expressing each allele

dosage compensation

inactivation of one X in female cells gives equal levels of expression of X-linked genes in male and female cells

epigenetics

types of changes in gene expression that are at a level that goes beyond changes in DNA sequences

epigenetic effect

begins with an initial event that causes a change in gene expressionlong-term maintenance of a change in gene expression

epigenetic inheritance

Modification of a gene or chromosome during gamete formation or early embryonic development, to change gene expression in a way that becomes fixed for that individualPermanently affects the phenotype of the individual, but not permanent over the course of many generations Does not change the sequence of DNA nucleotidesX inactivationGenomic imprintingEnvironmental agents

genomic imprinting

A segment of DNA is imprinted, or marked, in a way that affects gene expression throughout the life of the individualoccurs in flowering plants and mammalsCan involve a single gene, part of a chromosome, an entire chromosome, or all the chromosomes from one parent

lgf-2

an imprinted geneNormal and dwarf offspring can have the same genotype but different phenotypesIn mammals, only the paternal Igf-2 gene is expressedA male can inherit a methylated gene from his mother that is never transcribed – but he can pass on an active, nonmethylated copy of this exact same gene to his offspring

Population ecology

the study of populations in relation to their environment, including environmental influences on density and distribution, age structure, and population size

population

group of individuals of a single species living in the same general areaare described by their boundaries and size

density

number of individuals per unit area or volumeMark-recapture method

dispersion

pattern of spacing among individuals within the boundaries of the population

population density is determined by immigration/emigration

Dispersion patterns

clumped, uniform, random

clumped

Most commonResources tend to be clustered in natureSocial behavior may promote this pattern

uniform

Competition may cause this patternMay also result from social interactions such as            territoriality

random

RarestResources are rarely randomly spacedMay occur where resources are common and abundant

life history

An organism’s ___ _____ comprises the traits that affect its schedule of reproduction and survival

survivorship curve

plots numbers of surviving individuals at each age

Reproductive strategies

semelparity, iteroparity

semelparity

produce all offspring in single reproductive eventIndividuals reproduce once and then die

iteroparity

reproduce in successive years or breeding seasons (humans)Seasonal – distinct breeding seasonsContinuous — reproduce repeatedly at any time of the year

Reproductive strategy

has a strong effect on subsequent age classes of a population

per capita rate of increase / populations growth size