bio 106 midterm vocab

induction

specific observation to broad generalizations and probable conclusions 

• testable prediction

deduction

broad generalization and princples to specific conclusions with certainty

• hypothesis

replication

process of creating an exact copy of DNA, cells, etc

• The duplication of genetic material.

  Control untreated; used in experiments to compare with

  the variables

control

a group/set that has ordinary conditions

• no changes/experiment

• used to have a standard resultfor comparison in experiments.

allele

different forms of genes (mendels units, particles or factors) 

gene

a sequence of nucleotides coding for a protein; trait

genotype

the genetic constitution of an organism

• a combination of alleles that they possess for a specific gene

homozygote:

alleles that have both dominant or both recessive

• diploid organism that has two copies of the SAME allele

heterozygous:

alleles that have one dominant and one recessive

• contains two different alleles at a given locus

gamete:

mature reproductive/ sex cell that are haploids

• 23 chromosomes

• egg - female

  • sperm - male

dominant

an allele whose trait is expressed when in heterozygous condition

• trait that will mostly likely show uo

  • 3/4 chance of appearingr

recessive

trait will not appear/suppressed in heterozygous condition

• trait will only appear if no dominant allele

  • ¼ chance of allele showing

phenotype

observable traits/physical appearance of an organism trait that we can measure

haploid

single of set of chromosomes

• 23 chromosomes

diploid

two sets of chromsomes

• 46 chromosomes

  • all organisms are diploids

chromosomes

In bacteria and viruses, the DNA molecule

that contains most or all of the genetic information of the

cell or virus.

chromatid:

A newly replicated chromosome, from the time

molecular duplication occurs until the time the centromeres

separate (during the anaphase of mitosis or of meiosis ).

centromere

The region where sister chromatids join.

genetic drift: Changes in gene frequencies from generation

to generation as a result of random (chance) processes.

founder effect

the reduced genetic diversity which results when a population is descended from a small number of colonizing ancestors

• Random allele changes that happen when a small group starts a new population

bottleneck effect

Effect which occurs when the number of

individuals in a larger population are drastically reduced by

a disaster

• when population decreases from natural disaster

• By chance, some alleles may be overrepresented and

  others underrepresented among the survivors

  • This reduces variety and adaptability in the gene pool

male-mal competition

males compete with one another to attract females, part of sexual selection

female choice:

females chooses mate based on behavior, appearance, and smell

• females actively select their desired mate

adaptive radiation

When one ancestral species evolves into many related species, each adapted to different environments.

• a series of evolutionary events that result in an array (radiation) of relating species that live in a variety of environments, differing in the characteristics each uses to exploit those environments

reinforcement 

When natural selection strengthens reproductive barriers between already diverging populations, increasing their isolation

• won’t  breed together anymore → forming separate species

• The evolution of enhanced reproductive

  isolation between populations due to natural selection for

  greater isolation

• reinforcing the separation of species

allopatry

When a physical barrier (like a river or mountain) separates a population, leading to two new species

• The formation of two species from one whenreproductive isolation occurs because of the interpositionof (or crossing of a physical geographic barrier, such as arive

sympatry

speciation due to reproductive isolation without any physical separation of the subpopulation

• occurs in same geographic area

can be due to

• behavioral differences

• ecological differences

• genetic changes

taxon

a biological group (typically a species or a clade) that is given a name

• must be monophyletic

node 

each branching point on a phylogenetic tree 

tip

end point of a branch

• represents a group (species or larger taxon) that is living today or ended in extinction

• terminal node

clade

a monophyletic group made up an ancestor and all of its descendants

monophyletic

a group that consist of an ancestor and all of its descendants

• a clade

• one ancestor + all of its descendants

polyphyletic

pertaining to a group that consist of multiple distantly related organisms, and DOES NOT include the common ancestor of the gorup

paraphyletic

pertaining to a group that does include ancestor, and some, BUT NOT ALL of its descendants

convergence

independent evolution of similar features from different ancestral traits

• from similar environments or ecological roles

• similar selective pressures

• Example: Fins in dolphins (mammals) and sharks (fish) — both for swimming efficiently

homology

a similarity between two or more features that is due to inheritance from a common ancestor

• The forelimbs of humans, bats, whales, and cats all have the same bone structure (humerus, radius, ulna, etc.), showing a common evolutionary origin, even though they’re used for different things (grasping, flying, swimming, walking)

pre-zygotic isolating mechanisms 

factor that prevents individuals from different species from mating

• prevents mating before fertilization

• example: gametic isolation - sperm and eggs are incompatible

• example: temporal isolation: species breed at different times

postzygotic isolating mechanisms

a barrier that prevents hybrid zygotes from developing into viable, fertile individuals

• fertilization happens → offspring cannot survive or reproduce successfully

• post-fertilization barrier

directional selection

selection in which phenotypes at one extreme of the population distribution are favored

• graph shifts towards one side

stabilizing selection

selection against the extreme phenotypes in a population so the intermediates are favored

• graph increases in length

• range/diversity decreases

disruptive selection

selection in which phenotypes at both extremes of the population distribution are favored

• both ends increase

• middle dipped

artificial:

the selection by humans, plants, and animals breeders of individuals with certain desirable traits

artificial sexual

humans put two animals together to breed to get desired offspring/traitsna

natural

• the process by which traits that improve survival and reproduction become more common in a population over generations

• traits that re more likely to survive and reproduce

  • traits are then passed on to next gen → can change allele frequency of whole population

• charles darwin's theory that the features of an organism that help it survive and reproduce are more likely than other features to be passed on to subsequent generations

natural sexual

random mating between two animals

• not forced

sexual

the process where traits help an individual attract or compete for mates → becomes more common over generation

• An evolutionary mechanism by which traits that

increase the ability of individuals to attract or acquire

mates appear with increasing frequency in a population;

selection in which a mate is chosen on the basis of a

particular trait or traits

• peacock tail feathers

  • deer antler fight

intersexual

indivduals of one sex choose mates based on traits

• peacocok tail feathers

intrasexual selection

individuals compete with the same sex for access to mates

• deer antler fight

categorical values

contain a fix set of possible categories/finite number of categories or distinct groups.

• Categorical data might not have a logical order.

• For example, categorical predictors

include gender, material type, and payment method

discrete variables

numerical variables that have a countable number of values between any two values

• always numeric

• # of customer complaints

  • # of defects

continuous variables

numeric variables that have an

infinite number of values between any two values.

• A continuous variable can be numeric or date/time.

• For example, the length of a part or the date and time a

payment is received

dependent/response

hat you are testing or measuring; it depends on other factors

independent/explanatory

factor you can change or control to see if its affects something else

variable

thing that is being affected/changed in the experiment

synapomorphies

a trait that a group of organisms shares because they inherited it from a common ancestor

• it distinguishes them from other groups

morphology

the shape, size, and structure of an organism or its parts

derived traint

new trait that evolves in a species or group and was NOT present in its ancestors

ancestral trait 

present in common ancestor

homoplasises/analogous traits

similar traits that evolve independently in different lineages, not due to a common ancestor

• caused by convergent evolution

  • not shared ancestry

evolutionary reversal

when trait reversed from derived state & back to ancestralstate

notochord

flexible- rod shaped structures found in all chordate embryos that provide support along the body’s lengths 

lineage

series of ancestors and descendent population

descent with modification

the idea that organisms inherit traits from their ancestors, but changes (modifications) occur over generations, leading to diversity of lifespe

species 

group of individuals that can live and breed with each other

lineage system hierarchy

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

phylogeny

history of evolution relationships among organisms or their genes

phylogenetic tree

group of evolutionary related species are presented as branches

molecular clock 

method that uses the rate of genetic mutations to estimate the time since two species shared a common ancestor

scientific hypothesis is one that

a. leads to predictions that can be tested

b. uses deduction

c. is tenetative until repeated test fail to disprove it

d. all of the above

e. a and c

d. all of the above

biogeography

study of the distribution of species and ecosystems across geographic space and through geological time

neutral mutation

a change in DNA that does not affect an organism's fitness or phenotype, occurring in non-coding regions or as a "silent mutation" where the new DNA codon still codes for the same amino acid

molecular clock

tracks how long it has been since populations (or species) diverged.

• measures the genetic difference between species roughly constant rate over time

  • more differences → longer ago common ancestors lived

cyanobacteria

first photosyntheic organism 

primary endosymbiosis

The engulfment of a cyanobacterium by a larger eukaryotic cell that gave rise to the first photosynthetic eukaryotes with chloroplasts

• always internal

• gave rise to all of todays chloroplast

secondary endosymbiosis

The engulfment of a photosynthetic eukaryote by another eukaryotic cell that gave rise to certain groups of photosynthetic eukaryotes

symbiosis

a close, long-term interaction between two different species where at least one benefits

mutualism

biological relationship where two different species benefit from interacting with each other

• ex: chloroplast and eukaryotic

phylogenesis

the evolutionary development and diversification of a species or group of organisms, or of a particular feature of an organism

phylogenetic group

sets of organisms classified according to their evolutionary relationships

Types:

• monophyletic

• paraphyletic

• polyphyletic

coenocyte

an organism that contains many nuclei within each cell membrane

myxotrophic

microfilaments and contractile protein

commensalism

an association between two organisms in which one benefits and the other derives neither benefit nor harm

lateral and apical Meristems

• meristems - region of actively dividing cells in plants 

  • responsible for growth

• Apical meristems: responsible for primary growth of plants → make tall or longer

  • increase in length of roots + stems

  • new leaves and flowers

  • at the tip of roots and shoots

• Lateral Meristems: responsible for secondary growth → increases thickness or girth of plant

  • makes plant wider and stronger

  • along sides of stems and roots

stomata

small closeable openings in leaves and stems that are used to regulate gas exchange and water loss

tracheids

new cell type

• found in vascular plants

• is the principle water conducting element of xylem except for angiosperms and gnetophytes

• in gymnosperm and ferns

archegonium

multicellular flask shaped female sex organ that produces a single egg

• in a non-flowering plant

antheridium

• male sex organ where sperm produced in big numbers

• in nonflowering plants

xylem

• conducts water and minerals from soil/roots to aerial parts of plant

• provides support against gravity in terrestrial environment

phloem

conducts the products of photosynthesis from sites where they are produced or released to sites where they are used or stored

cortex

outer layer of ground tissue between outer skin (epidermis) and vascular tissue (xylem and phloem)

sporangium

reproductive structure in plants that contain and forms spores

• where mitosis takes place → produces genetically identical haploid spores

• in ferns and lower plants

vascular and ground tissue

vascular tissue: plants transport system → moves water, minerals, and food throughout the plant

• includes xylem and phloem

ground tissue: all plant tissue that is not vascular or part of outer layer

• forms most of the body of the plant

• includes parenchyma, collenchyma, and sclerenchyma

nonvascular land plants

lack specialized vascular tissues for the conduction of water or nutrients through plant body, and their life cycle depend on liquid water

• liverworts, mosses, and hornworts

spores

any asexual reproductive cell capable of developing into an adult organism without gametic fusion. In plants, haploid spores develop into gametophytes, diploid spores into sporophytes

sporophyte

in plants and protists with alternation of generations, the diploid phase that produces the spores.

gametophyte

the multicellular haploid phase that produces the gametes

heterosporous

In plants and photosynthetic protists with alternation of generations, the multicellular haploid phase that produces the gamete

• megaspore develops into female gametophyte → produces egg in megasporangia

  • microspore develops into male gametophyte → produces sperm in microsporangia

homospory 

single type of spore develops into a gametophyte that produces both eggs and sperm