Module 2 Bio Vocab

reproduction 1

how organisms make more individuals and pass on/change genotype 1

development

how to get a multicellular organism with differentiated cells, tissues, organs and a particular body plan

genotype

information stored in the DNA

phenotype

all structures, processes and behaviors of an organism

evolution

can only occur through changes in the hertiable traits of a biological population over generational time

phenotypic plasticity

the ability of individuals with a particular genotype to express different phenotypes as a result of environmental differences

monogenic traits

controlled by a single gene

polygenic traits

due to the action of multiple genes interacting with one another through intergrated pathways

continuous variation

variation clusters around average phenotype

discrete variable

a trait typically exhibits either one phenotype or another

phenotypic variation

always the result of the interaction between information from the environment and genotype

heritability

allows genotype component of phenotype to be passed on to offspring

overproduction of offspring

some of whom do not survive to reproduce

natural selection

differential survival of individuals with certain traits but not others

sexual selection

differential reproductive success of individuals with certain traits, but not others

DNA

double helix of base pairs containing the fundamental hereditary information of a living organism

chromatin

DNA combined with proteins

heterochromatin

condensed, densely packed

euchromatic

uncondensed, diffuse

chromosomes

discrete structures composed of chromatin

ploidy

number of types of chromosomes in a cell

haploid

1 N - one set of chromosomes

diploid

2N - two complete and different sets of chromosomes

polyploid

more than two versions of chromosomes

mitosis

eukaryote cell division that results in 2 genetically identical daughter cells

meiosis

eukaryote cell division that results in 4 genetically unique daughter cells

meiosis 1

eukaryote cell division that results in 2 genetically unique daughter cells

crossing over

the mechanism where homologous chromatids exchange corresponding segments of DNA

independent assortment

the mechanism where homologous pairs line up randomly in meiosis 1, leading to random chromosome combinations in daughter cells

meiosis 2

mitosis of 1 N daughter cells

purpose of genetic recombination

offspring genotypes are unique from parental genotypes

conjugation/lateral gene transfer

sexual reproduction of unicellular organisms

advantages of sexual reproduction

hedging bets and red queen hypothesis

hedging bets

if environmental conditions change, having offspring with a wide range of phenotypes will ensure that at least some will survive/pass on genes

red queen hypothesis

other organisms are constantly evolving, changing biotic conditions. genetic recombination creates favorbale combinations of genes to rapidly keep up

disadvantages of sexual reproduction

offspring only receive half a parents genes, difficult to mate, mates must be genetically compatible, offspring may be less fit than parents 

gene

a segment of DNA that contains the instructions for building a specific protein or performing a particular function

locus

the physical location of a gene sequence on the DNA strand

allele

functionally different variants of a gene, diploid organisms will have two of these each gene

homozygous

a diploid individual that contains two functionally identical alleles of a particular gene

heterozygous

a diploid individual possessing two different alleles for a gene

simple dominance

organism will display the phenotype of the dominant allele if it inherits at least one

partial or incomplete dominance

each genotype is associated with a distinct phenotype

semi dominance

heterozygote’s phenotype is exactly intermediate between the phenotype of each homozygote

co-dominance

both alleles contribute equally to the pheontype; often they are also dominant over other alleles

epistasis

one gene alters the phenotypic effect of another gene

pedigree inheritance

the study of how traits are transmitted across generations by analyzing family trees to identify genetic patterns

autosomal dominant inheritance

only one copy of the altered allele (from either parent) is needed for an individual to show the trait or disorder, inidividuals who inherit the allele show the trait - theres no hidden carrier state

autosomal recessive inheritance 

individuals must inherit two copies of the altered allele to show the trait or disorder

genetic linkage

genes are close together on the chromosome get inherited together

aneuploidy

atypical number of chromosomes (too many or too few)

gene dosage

number of copies of a particular gene

reproduction

the process that allows organisms to create new individuals

No alteration of Sexual Production

diploid organism has germ cells that undergo meiosis to product gametes for sexual reproduction

alternation of strategies

diploid organisms can undergo asexual reproduction or produce gametes via meiosis for sexual reproduction

alternation of generations

cells of diploid organisms undergo meiosis to product spores, which both grow and produce gametes via mitosis

unicellular asexual reproduction

binary fission

multicellular asexual reproduction

parthenogenesis, budding, regeneration, vegetative propagation

parthenogenesis

development of offspring from unfertilized gametes

budding

new individuals form as outgrowth from body of older individual

regeneration

growth of new individual from pieces of older individual

vegetative propagation

term for budding/regeneration in plants

spawning

release gametes into environment

intermittent organ

direct transfer of gametes

spermatophore

indirect transfer of gametes

gametes

haploid cells that fuse together in sexual reproduction

female

organisms that typically produce fewer, larger gametes

male

organisms that typically produce more, smaller gametes

pheromones

chemical substances used for communication between individuals of the same species

monoecious

a single individual produces both male and female gametophytes and may be capable of self-polination/cross polination

doecious

female and male gametophytes are produced by different individuals, who are incapable of self-pollination

development

formation of a complex multicellular organism from a single cell

polarity

establish axes of symmetry in early development

cleavage

growth via cell division throughout embryo development

migration

cells move in animal development

germ cells

give rise to gametes, are set-aside very early in development

somatic cells

all cells of the body, except those specialized for reproduction, all genetically identical

ectoderm

outermost germ layer, gives rise to skin and nervous system

mesoderm

middle germ layer, gives rise to muscles, circulatory systems, excretory systems, bones

endoderm

innermost germ layer, gives rise to lining of the gut and derivatives

gastrulation

radical movements reposition cells in the three germ layers to generate a mulit-layered organism

organogenesis

rearrangement of tissues to form distinct organs and organ systems

neurulation

formation of the neural tube (spinal cord and brain)

somitogenesis

formation of protective vertebrae and muscle blocks

differential gene expression

activation of different sub-sets of genes in different cells that is necessary for cell specialization

cellular signaling

signals sent between cells, receiving cells respond by activation or inhibition of different sub-sets of genes

cell fate and differentiation

differential gene expression and cell communication provide positional information to cells across the embryo, resulting in cell determination and differentiation

patterning

differential expression of homeotic genes establishes specialized body regions and location of structures

housekeeping genes

certain portions of the genome expressed by all cells, concerned with basic cell maintenance and function

transcription factors

regulate the expression of other genes, they may activate or inhibit expression of a given gene

induction

secretion of chemical signals by one group of cells to nearby target (responder) cells

morphogens

chemical signals

concentration and competency to respond

what determines how an inductive signal will be interpreted by a responder cell

cytoplasmic segregation

how embryos generate polarity; delocalization of maternally-derived mRNAs and proteins

determination

the process that sets a cell’s overall fate

differentiation

the process of becoming a specialized cell

stem cells

animals repair tissues using these cells that can migrate to a damaged area then differentiate into appropriate cell types

meristem cells

plants repair damage by having cells that can de-differentiate to become these cells and then re-differentiate to produce needed structures

homeotic genes

master control genes

purpose of homeotic genes

initiate a cascade of gene expression, affects the timing and amount of synthesis of proteins encoded by large number of genes (ex. Hox genes and Organ Identity genes)