Key Terms BIO

Biology

study of life

unity of life

all living things are descended from one common ancestor

Diversity of Life

Differences among living organisms results from evolutionary changes over time

Science

A way of understanding the natural world based on the accumulation of observable, testable, and repeatable evidence

Fact

An objective verifiable observation (A piece of data)

Hypothesis

A tentative explanation for a pattern of observation; is a possible answer to your question

• testable and falsifiable

Theory

A general explanation that has been test many, many times without being rejected; a hypothesis that is extremely likely to be correct (Based on repeated testing)

Evolution

Change in genetic make up of a population over time throughout generations

*No reproduction = No Evolution

Adaptation

Change that increases chances of survival or reproduction

• specific to the environment

Independent

the factor that the researcher changes or manipulates

Dependent

The factor that you observe and measure to see how it responds

Origins of GV (Random Fertilization)

Random Combination —> Zygotes inherit random combination of maternal and parental gametes

Humans= 2²³x2²³ = over 70 trillion possible combinations

Origins of GV (independent assortment during meiosis)

When they line up; gametes inherit random combinations of maternal and paternal chromosome

Origins of GV (recombination during meiosis)

Crossing over mixes up maternal and paternal alleles

Segregation of copied DNA into new cells

Segregate them into daughter cells (In eukaryotes mitosis or meiosis); both will end up separating out into new cells

Homologous Chromosomes

Are two versions of the chromosomes that are the same size and shape and carry the same genes inherited from 2 different parents

Cytokinesis

This is the process where it makes those new cells; So when plasma membrane and the cytoplasm divide into new cells

Sister chromatids

Are identical DNA molecules produced from DNA replication that are together

DNA replication

Is a copy of DNA; they basically go from one strand of DNA to two identical strands of DNA

Haploid (1n)

One of each type (length/gene) of chromosome

Diploid (2n)

One type of chromosome from each parent in a pair

=4 chromosomes

Genetics

variation is going to change overtime by evolution

Evolution

the process of change in variation with a population; change in allele frequency within a population over time

Mutation

occurs as a mistake during DNA replication

Phenotype

The physical expression of the genotype

Gene Pool

All alleles for all genes in a population

Genotype

Genetic make up that has a combination of 2 alleles

=1 per person

Alleles

Different versions of a gene (different DNA sequence)

=2 per person

Chromosomes

are long strings of DNA wrapped around proteins to make them compact

Genes

you have a chromosomes with some genes on it and those genes are going to be responsible for producing the traits of the organism

Fitness

Some phenotypes survive and reproduce more often which pass on their alleles more; one individuals relative genetic combination to future generations or “how many of your alleles are you passing on relative to everyone else in the population”

Lamark (1795)

he thought inheritance of acquired characteristics

• basically an organism uses a trait a lot during its lifetime then that can change the trait and pass it down

• WRONG!!

Gregor Mendel

Basic idea that you have different alleles and those different alleles are responsible for different phenotypes or “different alleles cause phenotype variation”

Natural Selection

Unequal survival and reproduction based on heritable variation in phenotype

• leads to adaptation

Non random mating

individuals with a population mate nonrandomly with respect to their genotype

assortative

Similar “Like w/ like” (inbreeding)

Disassortative

opposites attract

Genetic drift

any kind of change in allele freq as a result of random chance

• reduces genetic variation

Population

Group of organisms that are all the same type that might interbreed with each other

• we often see variation

Variation

Linked to the formation of new species and success of these different kinds of habitats

Discrete traits

Where phenotype has either or distant alternative

ex. color/shape

• controlled by a single gene

polygenic

controlled by many genes

ex. skin color —> ranges of colors

quantitative traits

continuous variation —> makes it hard to keep track

usually polygenic

Hardy-Weinberg equilibrium

Helps us predict what populations look like under goin evolution

Darwin and Wallace (1858)

descent with modification, pre-existing variation, more get passed down than others

Gene flow

a physical movement of genes from one population to another

Mutation

A change in the DNA sequence; nucleotides error during DNA replication

What increases mutation"?

• chemicals and x-rays

Founder effect

get a sample from large population and send it out to the new location or “relocation”

bottleneck

parent population is going to die by large event; those who survive is random these reestablish population

Biogeography

the geographical distribution of species

Homologous structures

Underlying structural similarity inherited from a common ancestor

Vestigial structure

No apparent function but retained from ancestor

ex. whale pelvis and wisdom teeth

Analogous structures

Appear similar but not because of common ancestry

Lack of variation

Natural selection only acts on existing variation —> nothing is new

Epistasis

involves multiple genes affecting one phenotype; when multiple genes contribute to given phenotype

Pleiotropy

When a gene has more than one effect or gene has multiple phenotypic effects

• prevents a perfectly adaptive allele

Trade offs

improve a particular trait in one way, very often that trades off with a cost in another way

• “Nothing is free”

Evolutionary History

Work with what given only tinker with phenotypes that were previously existing within population

• change in trait function over time

• anatomical, physiological, or genetic constraints

coevolution

change in one species in response to change in another species

multiple evolutionary mechanisms

other mechanism may act to reinforce natural selection, or counter it

Oscillating Selection

when environment swings back and forth between extremes as a result the type selection; what selection prefers will also swing back and forth as the environment changes

heterozygote advantage

any situation in which heterozygote have higher fitness than either homozygote

sexual dimorphism

when their are two different forms of the sexes

• girls look one way and guys look another way

Intrasexual selection

within one sex, male-male competition

intersexual selection

Between both sexes; where one Individual of one sex prefers a particular mate of other sex

• look for the attractive one

Directional selection

Where one phenotypic extreme with the variation in the gene pool is favored over all other

Stabilizing Selection

Intermediate phenotypic favored —> middle

Disruptive Selection

Where the ends of both extremes are favored and the average is worse

radiometric dating

used to assign absolute dates to rocks/fossils

• based on radioactive isotopes

• decay at a constant rate w/ half life

Sedimentary rocks

formed at the bottom of bodies of water as sediment accumulates due to gravity

• layers indicate relative dating

artificial selection

• selection imposed by humans

• rapid experimental selection

• alleles become more common b/c we choose it

• similar to natural selection

Convergent evidence

two lineages that are not that closely related that starts out w/ different phenotypes but over time they converge on the same phenotype

Hox genes

set of genes responsible for setting up the development or the body plan in an embroyo

Natural selection

selection for traits related to reproductive success

• tends to produce extreme phenotypes

Postzygotic barriers

prevents development of viable fertile offspring

hybrid infertility

the hybrid offspring cannot successfully reproduce

Hybrid inviability

the offspring of 2 different species dies early or develops improperly

reproductive isolation

keeps species distant from one another & prevent the successful formation of a fertile viable offspring

prezygotic barriers

prevent formation of a zygote; prevents successful fertilization of egg to form a zygote offspring

morphological SC

a group of organism with similar phenotype or they just all look the same

Biological SC

group of organism that can interbreed to produced viable, fertile offspring

Phylogenetic SC

Smallest group of individuals that share a common ancestor

Ecological SC

group of organism adapt to use a specific/particular niche in the environment

polyplody

many sets of chromosomes more than 2

due to errors in the mitosis and meiosis

adaptive radiation

rapid diversification of many species from a single ancestral species

Character displacement

evolution of adaptations that minimize competition

Allopatric Speciation

Population are separated geography by physical barrier (Common)

leads to —> mutations, natural selection, gene drift

Sympatric Speciation

Speciation of two populations that are in the exact same geographic area —> no physical barrier

Leads—> polyploidy, sexual selection, habitat differences

Parapatric Speciation

geographic neighbors are more likely to mate

Homologous traits

those traits inherited from a common ancestor as a result they share a evolutionary history

homoplastic traits

Those traits who look similar but not the result of common ancestry

ingroup

set of taxa that you are interested in understanding

outgroup

a closely related taxon that is not ingroup

• helps us determine what the ancestor might have looked like

useful for inferring phylogenies

synapomorphies or shared derived traits

—> derived out of the ancestral

polyphyletic group

“Worse”

—> would not include common ancestor of everybody

paraphyletic Group

a group that includes a common ancestor and some of its descendants but not all of its descendants leaves one out. “bad”

Monophyletic Group

“good” true clade; includes a common ancestor and its descendants

Molecular Clocks

locks at DNA Sequence to try to assign dates to divergence events in phylogenies

Ice Cores

produced when scientist drill down into glaciers, and they extract a core of ice and that ice has bubbles w/ the concentration of gases present before

Continental drift

Plates over time as a result of upwelling of this magna