BIO120 Midterm 2 Flashcards
taxonomic diversification
divergence causing a change in species name
Taxonomy
The scientific study of how living things are classified; like the vocabulary to the grammar of systematics
Carol Linnaeus
Father of Taxonomy; established his classification of living things; famous for animal naming system of binomial nomenclature; came BEFORE Darwin
sympatric
within a region
Allopatric
across regions
taxonomic (morphological) naming of species
naming based mostly on distinct measurable differences
biological naming of species
naming based on inter-fertility
Biological Species Concept (BSC)
Defines species as groups of interbreeding populations that are reproductively isolated from other groups
allopatric speciation
The formation of new species in populations that are geographically isolated from one another.
vitelline envelope receptor (VERL)/Lysin interaction
- an example of a reproductive isolating barrier (prezygotic barrier) in Lecture 9
- VERL (egg of abalone) only takes specific lysin sperm.
- Like a molecular “lock and key”
pre-zygotic barriers
A reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted@ so NO zygote gets formed (geography@ ecology@ temporal@ behaviour@ mechanical [genital compatibility]@ cellular)
apple maggot flies
have different timing of mating depending on preferred host plant; example of prezygotic barrier because the different mating periods reduces fly gene flow by 94%!!! in sympatry
post zygotic barriers
- caused by?
- favoured by natural selection?
- prevent proper functioning of zygotes once they are formed;
- caused by combinations of genes with low fitness in the hybrid;
- CANNOT be favored by natural selection;
Intrinsic Postzygotic Barriers
hybrid inviability@ hybrid sterility@ or abnormal development of hybrids
Extrinsic Postzygotic Barriers
mismatch of phenotypes in hybrids to environment
sterile
incapable of reproducing
Hinny
cross of a male horse and female donkey; opposed to mules which is vice versa. example of intrinsic postzygotic isolation in lecture 9
Heliconius butterflies
example of extrinsic post-zygotic isolation; CAN form hybrids@ but those hybrids can’t mate and are less viable
ecological speciation
the evolution of reproductive barriers between populations by local adaptation
4 things commonly ID an adaptive radiation:
1) recent common ancestry
2) phenotype-environment correlation
3) trait utility
4) rapid speciation
clade
A group of species that includes an ancestral species and all its descendants.
hybridization
the exchange of genes between species
what causes adaptive radiations?
1) ecological opportunity
2)key innovations
3) high rates of speciation to characterize the clade
ploidy
is the number of complete sets of chromosomes in a cell
polyploidy
A chromosomal alteration in which the organism possesses more than two complete chromosome sets. A form of sympatric speciation
allopolyploidy
- least or most common type of polyploidy?
- two or more complete sets of chromosomes
- polyploidy resulting from contribution of chromosomes from two or more species;
- most COMMON type of polyploidy
Autopolyploidy
arises from duplicated karyotype within a species; an individual that has more than two chromosome sets that are all derived from a single species
Karyotype
an individual’s complete set of chromosomes
speciation continuum
- continuous sequence of genetically-based changes that occur as two lineages diverge from one another on the pathway to reproductive isolation.
- SPECIATION IS NOT A UNIDIRECTIONAL PROCESS
polyploids are _________ _____________ from their diploid parents
reproductively isolated
hybrid vigor
A phenomenon in which the hybrid state is selected because it has greater survival and reproductive success; also known as heterosis
Larmack’s theory
all organisms have an inherent tendency to become more complex; wrong! only some lineages have evolved greater complexity in terms of cells@ tissues types@ physiology@ development@ reproduction@ social behaviors ect.
greater complexity arises from greater ____________ amongst previously independent units; independent of each other to dependent of each other. Human interaction is an example.
cooperation
division of labor
specialization of parts to specific functions. (think intestines do something different to lungs and neither do both jobs)
merging of prokaryotes
in lecture 11 to exemplify greater complexity via merging
individual selection
natural selection of individual characteristics; usually stronger than “group selection” this might not always be good for the SPECIES
unit of selection
biological entity within the hierarchy of biological organization that is subject to natural selection
peacocks
example in lecture to show how evolution isn’t perfect@ illustrating that the individual selection outweighs the group selection There is a cost to increasing sexual fitness because the risk of predation is increased
reciprocal altruism
an organism acts in a manner that temporarily reduces its fitness while increasing another organism’s fitness@ with the expectation that the other organism will act in a similar manner at a later time; repeated cooperation. think prison dilemma
high relatedness
a mode of adaptive cooperation; genes lead to helping relatives can spread via natural selection: think oldest child growing up to help parents raise own kids
cooperation is capable of ______ because of “cheaters”; both side might not benefit
breaking down
genes
the unit of inheritance. THE TARGET OF SELECTION; _________ typically persist by improving the fitness of the GROUP
fair representation is ensured by:
- Ensured by mitosis and meiosis
- genes vary so alleles can’t compete within an individual
chimera of zygotes
example in lecture 11: to describe initial competition between cell lineages. when two cells in early development fuse and induces internal competition
meiotic drive
- allele biases its own transmission spreading to higher frequency even while reducing fitness;
- CAN RAPIDLY ELIMINATE ALLELES THAT HAVE HIGHER INDIVIDUAL FITNESS
transposable elements
- DNA sequences that have the ability to change their position within a genome.
- can make over 50% of DNA in genomes of some species@ so selfish!!!!
starting from a _______ prevents initial competition between cell lineages
single cell
piRNA and RNA interference
have evolved as silencing mechanisms of transposable elements; or else genomes will EXPLODE!!!!
- an example of how individual selection favors alleles arising elsewhere that silence TEs@ preventing CHEATING
Mutations in genes for _____________________ leads to rampant activation of TEs; this is NOT good. CHEATING!!!!
DNA methylation
uniparental inheritance
- what does this prevent?
- inheritance pattern in which the progeny have the genotype and phenotype of one parent only
- i.e - chloroplasts and mitochondria replicate asexually;
- this PREVENTS COMPETITION within cells of different organelle genomes
transposition-selection balance
- definition
- occurs when?
- an equilibrium in the number of deleterious alleles in a population
occurs when:
- the rate at which deleterious alleles are created by mutation
=
- the rate at which deleterious alleles are eliminated by selection
mitochondrial transmission
- lack of mitosis and meiosis of organelles sets up potential for spread of selfish elements;
- MAINTAINS COOPERATION (eg active exclusion of sperm mitochondria at fertilization)
Uniparental inheritance has CONFLICT OF INTEREST!!! mitochondrial mutations that enhance __________ fitness can spread even if cost is severe to male fitness
maternal