Midterm review questions, complete set
Induction: Taking a specific observation and generating a general observation. See something and
think of a reason why that happens. Hypothesis forming from a specific detail and make general
reason. This happens early on
Deduction: Take that hypothesis and make specific predictions, test those predictions and if they’re
true. It is very hard to prove that something is true so you can disprove hypothesis what we try to do.
We come up with predictions and test them, and the less you get wrong, the more you can relate it to
specific. Test the hypothesis to specific thing.
Replication: The ability for the experiment to be done over again and have the same results, this
makes for good science
Control: Group that must be constant in the experiment in order to have something to compare the
results to. There can only be one variable at a time present.
Allele: Alternate versions/forms of gene for a certain trait such as different blood types or whether or
not sickle cell anemia is present
Gene: Living beings depend on genes, as they specify all proteins and functional RNA chains. Genes
hold the information to build and maintain an organism's cells and pass genetic traits to offspring
Homozygote: Diploid organism with two copies of the same allele at a given locus (locus is the
location of gene on chromosome) -AA or aa
Heterozygote: There are two different alleles/version of a gene at a given locus but still code for the
same thing- Aa
Gamete: Sex cells of individual, for humans it is the sperm and the egg and they are haploid, contains
23 chromosomes instead of 46 like a normal diploid cell.
Dominant: Allele whose trait is expressed when heterozygous (Aa… thing that A codes for will be
expressed)
Recessive: Allele whose trait is suppressed when heterozygous.
Phenotype: Physical appearance of an organism. This trait is measurable
Genotype: Genetic constitutional/make up of an organism.
Haploid: 1n, single set of chromosomes. Gamete fusion recovers diploidy
Diploid: 2n, two sets of chromosomes, we humans are diploid and have one set from mom and one
set from dad
Chromosome: packaged and organized chromatin, a complex of macromolecules found in cells,
consisting of DNA, protein and RNA. The main information-carrying macromolecule is a single piece
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, Midterm review questions, complete set
of coiled double-stranded DNA, containing many genes, regulatory elements and other non-coding
DNA.
Chromatid: A chromatid is one-half of two identical copies of a replicated chromosome. During cell
division, the identical copies are joined together at the region of the chromosome called the
centromere. They are known as sister chromatids. Once the paired sister chromatids separate from
one another in anaphase of mitosis, each is known as a daughter chromosome.
Centromere: A region on a chromosome that joins two sister chromatids. In prophase of mitosis,
specialized regions on centromeres called kinetochores attach chromosomes to spindle polar fibers.
These fibers help to manipulate and separate chromosomes during cell division.
Genetic Drift: When allele frequencies change due to random change, more common in smaller
population size
Founder Effect: Geographic isolation that kept a species out of the area, and a few individuals
founded a new population and whatever genes/alleles the individuals bring to the population will have
a huge effect on the allele frequency. Yellow butterfly goes over a bridge and now all the butterflies
have a yellow population on the other side
Bottleneck: When population is temporarily reduced in size, the population that builds up from those
few survivors and has their allele frequency. This is what happened to cheetahs and even possibly
humans because of the lack of variation (very homogenous). We can sample genetic diversity and if it
is much lower than we expect, it could be because it went through a population bottleneck
Male-Male Competition: An idea of Darwin which explained that males with better features, for
example the peacock feathers for appearance and stronger horns for fighting over a mate, played a
role in sexual selection and therefore increased fitness on average
Female Choice: This causes quick evolution for different traits because when female choses who she
wants to mate with (variation) causes reproductive isolation and then causes for divergent of traits
such as fancy feathers, and different displays the birds can make. (Birds of paradise much more
variation of species in genus verses other species with the same genus)
Adaptive Radiation: Any feature of organism that increases fitness on average and allows for better
reproductive success and chances of survival than it would have with preexisting environmental
conditions. It is not teleological and individuals do not evolve, they either have the trait or not, but
populations evolve (average of traits in populations change).
Artificial: Humans deliberately determine reproductive success, when we want to breed certain traits
into organisms and determine the selective environment by raising temperature or plucking out plants
that we don’t want. Examples are pigeons with tail feathers and vegetables related to wild mustard.
Natural: Maintains genetic variation, good for HETEROZYGOUS & FREQUENCY DEPENDENT,
can be affected by epistasis which is a continuous process where 1 gene affects multiply traits and
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polygenism where many genes affect one trait. It can be discreet like eye color or continuously
varying traits are like life span, height, weight, age of reproduction, blood cell count
Directional: Favors one direction. When there is never snow the darker hair color in mice
increases in mean value
Stabilizing: Favors the average middle. No snow or climate change for the mice so we lose
some variation for the trait
Disruptive: Favors the extreme. One of the mice matches the concrete and the other matches
the soil and the intermediate does not do well.
Sexual: Form of natural selection, fitness is defined by access to mates rather than by work
conditions of survival. This causes the variation in feathers. Species with this has more dimorphic
sexual traits. This also has more species like the birds of paradise.
Reinforcement: Species become more different and this is reinforced are when hybrids are less fit, so
strong selections to stop mating with the wrong species.
Allopatric: Living in geographically isolated areas, species are divided by some barrier and then
diverge and eventually become species. It is easier and more common form because it is easier to
become reproductively isolated if they cannot meet each other because there is no gene flow (coco
island) have 1 species vs. Galapagos with repeated colonization leads to 13 different species (repeated
founder events which lead to new species like drosophila). When barriers go away, they can…
Fuse: When the species has not been reproductively isolated for a long enough period of time
Hybrid Zones: Partial reproduction is not complete. Narrow stable hybrid zone restricts gene
flow by preserving it. A wide hybrid zone are on the way to fuse and become single species.
Extinction of one population
Fuse into new species
Reinforcement
Sympatric: Living in same geographic areas and is much harder. There must be a genetic gimmick
like polyploidy (mistake in meiosis) there are different number of chromosomes which means groups
are not reproductively compatible.
Taxon: Any named group of organisms… Homo sapiens, Birds, flowering plants, Felidae. Could be a
single species, could be all the birds. Try to group taxa into clades because they share a common
ancestor
Node: The ancestors of a pair or group of taxa, the branching points where they split
Tip: The descendant taxa, ends of a phylogeny tree
Clade: A group that includes a common ancestor and all of its descendants. It could include one or
many taxa
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