bio midterm 1
terms and concepts from lecture and a few from the book on material before midterm 1.
Terms
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- polyphyletic
- descendants of more than one most recent common ancestor
- spatial isolation
- geographical barrier prevents mating
- Hybrid Sterility
- Offspring is sterile so no further gene flow can occur (ex. horse + donkey= sterile mule)
- Types of chromosomal aberrations(7)
- euploidy, aneuploidy, polyploidy, inversion, translocation, deletion, duplication
- population
- a unit of species comprising of organisms that interbreed
- Pleiotropy
- Genes that have more than a single effect on phenotype
- Hardy- Weinberg Equilibrium conditions (5)
- large population size, random mating, no mutation, no migration, no allelic advantage
- Mechanisms of Pre-Zygotic Reproductive Isolation
- spatial, temporal, ecological, behavioral, mechanical, gametic
- species
- a group of actually or potentially mating interbreeding nautral populations that are reproductively isolated from other such groups.
- polyploidy
- the carrying of one or more additional sets of chromosomes
- Linkage
- all genes present on a chromosome are said to be linked
- Heterozygote
- consists of one dominant and one recessive allele
- sexual selection
- pushes (changes) a phenotype unitl natural selection occurs (feature loses functionality) ex. peacock spots
- Punctuated Equilibrium
- long periods of equilibrium punctuated by bursts of speciation
- Stasis
- stabliizing selection (unchanging phenotype)
- Meiosis
- Reduction division of gametes
- Cladogenesis
- splitting phenotype (speciation and disruptive selection)
- mendel's Laws
- formulated the principals of heredity and inheritance.
- duplication
- extra section attaches to a normal chromosome
- Genotype
- the possible outcomes - cannot be determined jsut by looking at phenotype.
- haploid
- (n) number of chromosomes in a single set, generally gametes
- directional selection
- individuals with higher fitness are at one tail of normal curve and a new curve shifts to adapt them
- deletion
- entire blocks of genes may be lost
- aneuploidy
- when a single chromosome is added or removed from a set
- Tertiary PRO structure
- complex shape (pleated/coiled fold to form chains)
- euploidy
- changes in chromosome numbers when there is the addition or deletion of whole sets of chromosomes
- gametic isolation
- fertilization does not occur due to protiens on sperm or egg rejecting gamete. (rejection on a bichemical level)
- Law Of segregation
- in the formation of gametes, paired factors specified alternative phenotypes segregate independently
- monophyletic
- ALL descendants came from one common ancestor
- Parapatric Populations
- two populations that share a border
- Disruptive selection
- favors the two extreme phenotypes and selects against the mean (mean does not shift over time)
- Homozygote
- consists of either both dominant or both recessive alleles
- behavioral isolation
- mating does not occur due to differing mating rituals (dances, ect...)
- Anagenesis
- directional selection (selecting toward one phenotype)
- Frequency dependent selection
- keeps both types around but population shifts due to fitness
- Sympatric Populations
- two popultions that overlap partially (moving apart while in the same space)
- diploid
- (2n) number of chromosomes in 2 complete sets, fertilized
- hybrid inviability
- zygote dies before birth- fails to develop
- quantitative Inheritance
- a phenotypic intermediate between two parents. polygenic traits controlled by more than one locus. ex: height.
- The Law of Independent Assortment
- Genes located on different pairs of homologous chromosomes assort independently during meiosis
- stabilizing selection
- favors the mean phenotype
- reproductive isolation
- when there is no gene flow
- Types of lineage (4)
- stasis, anagenesis, extinction, cladogenesis
- mechanical isolation
- mating does not occur due to reproductive parts not fitting together
- How a Phenotype/ trait is produced
- chromosome -> gene-> MRNA-> Translation-> Protien
- Extinction
- population dies out
- philogeny
- graphical rersentation of of the relationship of ancestors to descendents over time
- Qualitative Traits
- controlled by one genetic locus. ex eye color blue or green but nothing in between
- homologous chromosomes
- pair of identical chromosomes
- Quaternary PRO structure
- chain interaction
- Chromosomal Aberrations
- structural and numerical deviations from the norm that affect many genes at once.
- outgroups
- distant relatives that give information about ancestral relations of a clade
- Phyletic Gradualism
- slow steady change in a phylum with a steady accumulation of small changes
- Polyploidy
- when descendent taxa have more chromosomes than their ancestors (instant speciation)
- ecological isolation
- mating does not occur due to a subdivision of a habitat
- gene flow
- when genes can be exchanged through populations
- Relative Fitness
- number of ones offspring that survive to reproduce in comparison to population mean
- paraphyletic
- some but not all descendents of a most recent common ancestor
- Natural Selection
- the environment decides who survives and that genetic composition of the next generation
- synamorphies
- shared derived states that help decide which groups are sister taxa with in a clade
- Mechanisms of Post-Zygotic Isolation (3)
- hybrid inviability, hybrid sterility, hybrid breakdown (mating has occured)
- inversion
- rearrangement of linear order
- translocation
- the exchange of sections
- Secondary PRO structure
- pleated or coiled primary pro
- Allopatric Population
- two populations physically isolated in space
- Artificial Selection
- humans decide who survives based on desirable traits
- Natural Selection conditions (3)
- individuals vary with respect to phenotype, phenotype variation is heritable, phenotypic variation results in differential survival and reproduction
- Hybrid Breakdown
- hybrid is not as fit as either pure type.
- Stable polymorphism
- population under selection, edns up with 2+ different forms over time. (frequency dependent)
- Types Of populations (3)
- allopatric, parapatric, sympatric
- lineage
- populations moving through time
- Primary Protien Structure
- sequence of amino acids
- Crossing Over
- causes separation of alleles located on the same chromosome. frequency of crossing over is the distance between loci.
- epistasis
- an allele at one locus masking or preventing another allele at another locus acting on the same trait.
- heritablilty plot slope
- tell what percent of a characteristic is genetically determined. M=1 is completely gene determined, M=0 is telling you that genes have no effect on the outcome.