Term
| How is life distinguished from nonliving matter? |
|
Definition
| ability to produce more of their own kind |
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Term
|
Definition
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Term
|
Definition
| life of a cell from when its formed via division from a parent cell, until it divides into daughter cells |
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Term
| Cell Division is necessary in multicellular organisms for: (3) |
|
Definition
-Development from a fertilized cell
-Growth
-Repair |
|
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Term
|
Definition
| all genetic information within a cell |
|
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Term
|
Definition
| are packed with a cell's DNA molecules, which is further grouped into chromosomes |
|
|
Term
Order:
chromatin, chromosomes, DNA |
|
Definition
| DNA-> chromatin -> chromosomes |
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Term
|
Definition
| non reproductive cells, have 2 sets of chromosomes |
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Term
|
Definition
| reproductive cells (sperm&eggs) half as many chromosomes as somatic cells; a single set. |
|
|
Term
| What happens in preparation for cell division? |
|
Definition
| DNA is replicated and the chromosomes condense |
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Term
|
Definition
| joined copies of the original chromosome |
|
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Term
|
Definition
| "waist" of the duplicated chromosome, where the two chromatids are most closely attached. |
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Term
| Once separated, the chromatids are now called... |
|
Definition
| Chromosomes, and there are now double the number of chromosome in the cell. |
|
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Term
|
Definition
| Division of genetic material in the nucleus |
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Term
|
Definition
| Division of the cytoplasm. Begins during anaphase or telophase and the spindle eventually disassembles. |
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Term
|
Definition
| cell growth and copying of chromosomes in preparation for cell division. (90% of cell cycle) |
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Term
|
Definition
|
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Term
|
Definition
-G1 phase (1st gap)
-s phase (synthesis) chromosomes are duplicated
-G2 phase (second gap) |
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Term
|
Definition
1. prophase
2. prometaphase
3. metaphase
4. anaphase
5. telophase |
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Term
|
Definition
second gap.
Nuclear envelop encloses nucleus.
2 centrosomes formed from duplication of a single centrosome.
Chromosomes duplicated (during S phase) cannot be seen individually because they have not yet condensed. |
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Term
|
Definition
Chromosomes condense.
Nucleoli disappears.
Each duplicated chromosome appears as two identical sister chromatids joined at their centromeres
Miotic spindle begins to form.
centrosomes move away form each other. |
|
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Term
|
Definition
nuclear envelop fragments.
microtubules extending from each centrosome invade the nuclear area.
Each of the two chromatids of each chromosome now has a kinetochore.
Kinetochore microtubules jerk chromosomes back and forth.
non-kinetochore microtubules interact with those from the opposite pole of the spindle. |
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|
Term
|
Definition
Centrosomes are now at opposite poles of the cell.
Chromosomes line up at the metaphase plate.
For each chromosome, the kinetochore of the sister chromatids are attached to kinetochore microtubules coming from opposite poles. |
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Term
|
Definition
| structure made of microtubules that controls chromosome movement during mitosis. |
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Term
|
Definition
microtubule organizing center.
replicates during interphase (forming two centrosomes that migrate to opposite ends of the cell during prophase and prometaphase). |
|
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Term
|
Definition
| radial array of short microtubules that extends from each centrosome |
|
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Term
|
Definition
| Protein complexes associated with centromeres. During prometaphase, some spindle fibers attach here on the chromosome and begin to move them. |
|
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Term
|
Definition
| imaginary structure at the midway point between the spindle's two poles |
|
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Term
|
Definition
shortest stage of mitosis.
sister chromatids separate(each becoming a full-fledged chromosome) and move along the kinetochore microtubules towards opposite ends of the cell as kinetochore microtubules shorten. Non-kinetochore microtubules overlap and push against eachother, elongating the cell. |
|
|
Term
| NonKinetochore Microtubules |
|
Definition
| microtubules not attached to the kinetochores that elongate the cell. |
|
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Term
|
Definition
genetically identical daughter nuclei form at opposite ends of the cell. Nuclear envelopes arise from the fragments of the parent cell's nuclear envelope and other portions of the endomembrane system. Nucleoli reappear.
chromosomes become less condensed.
Any remaining spindle microtubules are depolynerized. |
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|
Term
Cytokinesis in:
Animal Cells
Plant Cells |
|
Definition
Animal Cells- cleavage furrow
Plant Cells- cell plate |
|
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Term
|
Definition
-Cell division used by prokaryotes
-Chromosome replicates and two daughter chromosomes actively move a part, followed by the plasma membrane pinching inward. |
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Term
|
Definition
1. Chromosome replication begins
2. Replication continues
3. Replication finishes
4. Two daughter cells result |
|
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Term
|
Definition
-Directs sequential events of the cell cycle.
-similar to a clock.
-regulated by both internal and external controls |
|
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Term
| Checkpoints (in the cell control system) |
|
Definition
| where the cell cycle stops until a go-ahead signal is received. |
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Term
| Importance of the G1 Checkpoint |
|
Definition
| if a cell receives a go-ahead signal it will usually complete the S, G2 and M phases the divide. If the cell does not receive the signal it will exit the cycle switching to a non-dividing state. (G0 phase). |
|
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Term
|
Definition
|
|
Term
| 2 types of regulatory proteins involved in cell cycle control |
|
Definition
| Cyclins and Cyclin-dependent kinases (Cdks) |
|
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Term
|
Definition
| concentrations vary throughout the cell cycle |
|
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Term
|
Definition
activity controlled by cyclins
cyclin-dependent kinases |
|
|
Term
| MPF (Maturation-promoting Factor) |
|
Definition
| a cyclin-Cdk complex that triggers a cell's passage past the G2 checkpoint into M phase. |
|
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Term
| Example of an Internal Signal acting on the cell cycle |
|
Definition
| kinetochoes not attached to spindle microtubules send a molecular signal that delays anaphase |
|
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Term
| Example of an external signal acting on the cell cycle |
|
Definition
| growth factors released or density-dependent inhibition |
|
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Term
|
Definition
| proteins released by certain cells that stimulate other cells to divide |
|
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Term
| Density-Dependent Inhibition |
|
Definition
| crowded cells stop dividing |
|
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Term
|
Definition
| animal cells must be attached to a substratum in order to divide |
|
|
Term
Loss of Cell Cycle Control:
Cancer Cells |
|
Definition
-exibit neither density-dependent inhibition nor anchorage dependence.
-do not respond normally to the body's control mechanisms: make their own growth factor, convey a growth factor's signal without the presence of the growth factor, have an abnormal cell cycle control system. |
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Term
|
Definition
| process by which a normal cell is converted to a cancerous cell |
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Term
|
Definition
| masses of abnormal cells within otherwise normal tissue |
|
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Term
|
Definition
| if abnormal cells remain only at the original site |
|
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Term
|
Definition
| invades surrounding tissues, can metastasize |
|
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Term
|
Definition
| exporting cancer cells to other parts of the body. |
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Term
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Definition
| scientific study of heredity and variation |
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Term
|
Definition
| transmission of traits from one generation to the next |
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Term
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Definition
| demonstrated by the differences that offspring show from parents and siblings |
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Term
|
Definition
| units of heredity that are made up of segments of DNA |
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Term
|
Definition
| sex cells (sperm & eggs) Haploid cells that are produced by meiosis |
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Term
|
Definition
| location of a specific gene on a certain chromosome |
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Term
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Definition
| single individual passes genes to its offspring without the fusion of gametes |
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Term
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Definition
| Group of genetically identical individuals from the same parent |
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Term
|
Definition
| 2 parents give rise to offspring that have unique combinations of genes inherited from the 2 parents |
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Term
|
Definition
| 2 sets of chromosomes. Any cell other than a gamete |
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Term
|
Definition
| ordered display of the pairs of chromosomes from a cell |
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Term
|
Definition
| 2 chromosomes in each pair that are the same shape and same genes that control the same inherited characters. Includes 1 chromosome from each parent. |
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Term
|
Definition
| determines sex of the individual called x and y |
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Term
|
Definition
| remaining pairs of chromosomes. Anything without an x and y. |
|
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Term
|
Definition
| N. contain one set of chromosomes. ex. gametes |
|
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Term
|
Definition
| 2N. has 2 sets of chromosomes ex. skin cell |
|
|
Term
| How many Chromosomes do Humans have? |
|
Definition
2N=46
N=23 (22autosomes&1sex chromosome) |
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Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| Fertilized egg. contains one set of chromosomes from each parent. |
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Term
| How does the Zygote develop? |
|
Definition
| produces somatic cells by mitosis and develops into an adult |
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|
Term
| 3 Main types of sexual life cycles that differ in the timing of meiosis and fertilization: |
|
Definition
1. Animals
2. Plants
3. Fungi and some Protists |
|
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Term
|
Definition
Gametes undergo no further cell division before fertilization.
Fuse to form a diploid zygote that divides by mitosis to develop to a multicellular organism.
Dominant life stage is as a diploid organism. |
|
|
Term
|
Definition
Both a diploid and haploid multi cellular stage.
Diploid organisms (sorophyte) makes haploid spores by meiosis.
Each haploid spore grows by mitosis into a haploid organism (gametophyte).
Fertilization of gametes results in a diploid sporophyte. |
|
|
Term
| Fungi and Protist Sexual Life Cycle |
|
Definition
Only diploid stage is the single-celled zygote; no multi cellular diploid stage.
Zygote produces haploid cells by meiosis; each haploid cell grows by mitosis into a haploid multi cellular organism.
Haploid adult produces gametes by mitosis.
Dominantly exist as a haploid. |
|
|
Term
| Two Sets of Cell Division in Meiosis |
|
Definition
Meiosis 1 and Meiosis 2.
Results in 4 daughter cells with half as many chromosomes as the parent cell. |
|
|
Term
|
Definition
| homologues pair up and seperate, resulting in two haploid daugter cells with replicated chromosomes |
|
|
Term
|
Definition
| sister chromatids seperate. Resulting in 4 daughter cells with unreplicated chromosomes |
|
|
Term
|
Definition
takes of 90% of the time.
Chromosomes begin to condense followed by synapsis.
Crossing over occurs.
Each pair of chromosomes forms a tetrad.
Each tetrad has 1 or more chiasmata |
|
|
Term
|
Definition
| when homologous chromosomes loosely pair up, aligned gene by gene |
|
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Term
|
Definition
| produces recombinant chromosomes, containing DNA inherited from each parent into a single chromosome. Homologous portions of 2 non-sister chromatids trade places. |
|
|
Term
|
Definition
|
|
Term
|
Definition
| x-shaped regions where crossing over occured |
|
|
Term
|
Definition
Tetrads line up at the metaphase plate, with one chromosome facing each pole.
Microtubules from each pole are attached to the kinetochore of one chromosomes of each tetrad.
Microtubules from the other pole are attached to the other chromosome. |
|
|
Term
|
Definition
pairs of homologous chromosomes seperate.
1 chromosome moves toward each pole, guided by the spindle apparatus.
Sister chromatids remain attached at the centromere and move as one unit towards the pole. |
|
|
Term
|
Definition
Each half of the cell has a haploid set of chromosomes; each chromosome still consists of two sister chromatids.
Cytokinesis occurs forming two haploid daughter cells |
|
|
Term
|
Definition
| sister chromatids seperate |
|
|
Term
| Telophase II and Cytokinesis |
|
Definition
| Haploid daughter cells form. Resulting in 4 daughter cells. |
|
|
Term
| 3 Events Unique to Meiosis (occur in Meiosis 1) |
|
Definition
Prophase 1- synapsis & crossing over: homologous chromosomes physically connect & exchange genetic info
metaphase 1- paired homologous chromosomes (tetrads) instead of individual replicated chromosomes
Anaphase 1- homologous chromosomes seperate instead of sister chromatids |
|
|
Term
| 3 Mechanisms that Contribute to Genetic Variation |
|
Definition
1. independent assortment of chromosomes
2. Crossing Over
3. Random Fertilization |
|
|
Term
|
Definition
| each pair of chromosomes sorts maternal and paternal homologs into daughter cells independently of the other pairs. |
|
|
Term
| # of combinations possible: |
|
Definition
2 to the power of N.
ex. humans- 2 to the power of 23= 8 million possible chromosome combinations |
|
|
Term
|
Definition
adds to genetic variation because any sperm can fuse with any ovum.
Each gamete has 8.4 million possible chromosome combinations from independent assortment.
Fusion of 2 gametes produces a zygote with any of about 70 trillion diploid combinations. |
|
|
Term
| Where does genetic variation originate from? |
|
Definition
|
|
Term
|
Definition
| the idea that genetic material from the two parents blends together. |
|
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Term
|
Definition
| the idea that parents pass on discrete heritable units (genes), explaining the reappearance of traits after several generations. |
|
|
Term
|
Definition
Augustinian Monk.
Experiments with garden peas beginning in 1857. |
|
|
Term
|
Definition
| distinct heritable features |
|
|
Term
|
Definition
character variants
ex) purple or white |
|
|
Term
|
Definition
| flowers can be cross-pollinated. Pollen (sperm) from the stamens applied to carpels (containing eggs). |
|
|
Term
| 3 Reasons why Mendel chose peas: |
|
Definition
1. Controlled mating could be done
2. peas have a short generation time and lots of offspring.
3. many varieties with distinct characters |
|
|
Term
|
Definition
| plants that produce offspring of the same variety when they self-pollinate |
|
|
Term
|
Definition
| process that Mendel used when he mated two contrasting, true-breeding varieties |
|
|
Term
|
Definition
|
|
Term
|
Definition
| hybrid offspring of the P generation |
|
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Term
|
Definition
| offspring of F1 individuals that self-or cross-pollinate with other F1 hybrids. |
|
|
Term
|
Definition
| offspring from two unique parents |
|
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Term
|
Definition
True-bred white and purple coloured pea plants.
All F1 hybrids were purple.
F1 hybrids crossed, many f2 plants had purple flowers, making that the dominant trait. 3 to 1 ratio. |
|
|
Term
|
Definition
1. Flower Colour: d-purple r-white
2. Flower Position d-axial r-terminal
3. Seed Colour d-yellow r-green
4. Seed Shape- d-round r-wrinkled
5. Pod Shape d-inflated r-constricted
6. Pod Colour d-green r-yellow
7. Stem Length d-tall r- dwarf
All with 3:1 ratio D:R |
|
|
Term
|
Definition
| alternative variations of a gene |
|
|
Term
|
Definition
| specific place on a specific chromosome |
|
|
Term
|
Definition
corresponds to the distribution of homologous chromosomes to different gametes in meiosis.
Accounts for the 3:1 ratio that Mendel observed in the F2 generation. |
|
|
Term
|
Definition
| the 2 alleles for a heritable character separate during gamete formation and end up in different gametes. |
|
|
Term
|
Definition
used to predict allele composition of offspring from a genetic cross between individuals of known genetic makeup.
Capital letter=dominant allele
lowercase letter=recessive allele |
|
|
Term
|
Definition
|
|
Term
|
Definition
| organism has two different alleles for a gene |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| breeding the mystery individual with a homozygous recessive individual. If offspring displays the recessive phenotype, the mystery parent must be heterozygous. |
|
|
Term
|
Definition
| individuals that are heterozygous for one character |
|
|
Term
|
Definition
| cross between such heterozygotes |
|
|
Term
|
Definition
| offspring of crossing two true-breeding parents differing in two characters |
|
|
Term
|
Definition
| a cross between f1 dihybrids, can determine whether 2 characters are transmitted to offspring as a package or independently |
|
|
Term
| The law of independent assortment |
|
Definition
each pair of alleles segregates independently of each other pair of alleles during gamete formation.
This law applies only to genes on different, nonhomologous chromosomes or those far a part on the same chromosome.
Genes located near eachother on the same chromosome tend to be inherited together. |
|
|
Term
| Deviation From Simple Mendelian Patterns |
|
Definition
Alleles are not completely dominant or recessive.
Gene has more than 2 alleles.
Gene produces multiple phenotypes. |
|
|
Term
|
Definition
| phenotypes of the heterozygote and dominant homozygote are identical |
|
|
Term
|
Definition
| the phenotype of f1 hybrids is between the phenotypes of the two parental varieties. Some cells show red and some show white which appears pink (not blending) |
|
|
Term
|
Definition
| two dominant alleles affect the phenotype in separate distinguishable ways |
|
|
Term
|
Definition
when genes have multiple phenotypic effects.
Responsible for the multiple symptoms of certain heredity diseases, such as cystic fibrosis and sickle-cell disease. |
|
|
Term
|
Definition
A gene at one locus alters the phenotypic expression of a gene at a second locus. ex. colour coat in Labrador retrievers
one gene determines the pigment colour; the other gene determines whether the pigment will be deposited in the hair. |
|
|
Term
|
Definition
| are those that vary in the population along a continuum. |
|
|
Term
|
Definition
additive effect of two or more genes on a single phenotype.
ex)skin colour |
|
|
Term
|
Definition
| phenotypic range of a genotype influenced by the environment. ex. hydrangeas of the same genotype range from blue-violet to pink, depending on soil acidity. ex tanning |
|
|
Term
|
Definition
| a family tree that describes the inter relationships of parents adn children across generations. |
|
|
Term
|
Definition
| heterozygous individuals who carry the recessive allele but are phenotypically normal |
|
|
Term
|
Definition
| autosomal dominant- if one parent has it the offspring have a 50/50 chance of inheriting it. Caused by single gene mutations on anyone of various locations on chromosomes 21, 14, and 1. |
|
|
Term
| The Chromosome Theory of Inheritance |
|
Definition
Mendelian genes have specific loci (positions) on chromosomes.
Chromosomes undergo segregation and independent assortment. |
|
|
Term
|
Definition
associating a specific gene with a specific chromosome.
experimented with fruit flies |
|
|
Term
|
Definition
|
|
Term
|
Definition
| traits alternative to the wild type |
|
|
Term
|
Definition
| gene located on either sex chromosome |
|
|
Term
| Y-linked vs. X-linked Gene |
|
Definition
y- on y chromosome. mainly encode genes related to sex determination.
x-on x chromosome. have genes for many characters unrelated to sex. |
|
|
Term
|
Definition
| on Y chromosome, codes for a protein that directs the development of male anatomical features. |
|
|
Term
| For a recessive x-linked trait to be expressed: |
|
Definition
| Female needs 2 copies of the allele, male needs 1 copy of the allele |
|
|
Term
|
Definition
| genes located on the same chromosome that tend to be inherited together |
|
|
Term
|
Definition
| production of offspring with combinations of traits differing from either parent, occurs due to crossing over. |
|
|
Term
|
Definition
pairs of homologous chromosomes do not separate normally during meiosis.
one gamete receives two of the same type of chromosome, and another gamete receives no copy |
|
|
Term
|
Definition
| abnormal number of a particular chromosome, results from the fertilization of gametes in which nondisjunction occured. |
|
|
Term
|
Definition
| condition in which an organism has more than two complete sets of chromosomes (common in plants, rare in animals) |
|
|
Term
|
Definition
|
|
Term
|
Definition
4 sets of chromosomes
AND SO ON. |
|
|
Term
|
Definition
| a deletion removes a chromosomal segment |
|
|
Term
|
Definition
| a duplication repeats a segment |
|
|
Term
|
Definition
| reverses a segment within a chromosome |
|
|
Term
|
Definition
| moves a segment from one chromosome to a nonhomologous chromosome. |
|
|
Term
|
Definition
1953.
James Watson and Francis Crick
Rosalind Franklin's x-ray crystallographic images of DNA enabled Watson to deduce that DNA was helical. |
|
|
Term
|
Definition
| subunits run in opposite direction |
|
|
Term
|
Definition
| polymer of nucleotides. Consists of a nitrogeneous base, sugar and a phosphate group. |
|
|
Term
|
Definition
| predicts that when a double helix replicates, each daughter molecule will have one old strand and one newly made strand. |
|
|
Term
|
Definition
replication begins here...2 DNA strands are separated, opening up a replication "bubble"
Replication proceeds in both directions from each origin, until the entire molecule is copied. |
|
|
Term
|
Definition
| Y-shaped region where new DNA strands are elongating. |
|
|
Term
|
Definition
| enzymes that untwist the double helix at the replication fork |
|
|
Term
|
Definition
| initial nucleotide strand is short (5-10 nucleotides long) synthesized by primase. |
|
|
Term
|
Definition
| enzyme that adds RNA nucleotides one at a time (starting at the 3' end) using the parental DNA as a template. |
|
|
Term
|
Definition
enzymes that catalyze the elongation of new DNA at a replication fork by adding nucleotides to a pre-existing chain. Proofread DNA.
DNA polymerases add nucleotides only to the free 3' end of a growing strand; therefore a new DNA strand can elongate only in the 5' to 3' direction. |
|
|
Term
|
Definition
| made continuously, moving towards the replication fork |
|
|
Term
|
Definition
| DNA polymerase must work in the direction away from the replication fork |
|
|
Term
|
Definition
| segments that make up a lagging strand |
|
|
Term
|
Definition
| joins okazaki fragment together |
|
|
Term
|
Definition
| repair enzymes correct errors in base pairing |
|
|
Term
| Nucleotide Excision Repair |
|
Definition
| Nuclease cuts out and replaces damaged stretches of DNA. |
|
|
Term
|
Definition
| special nucleotide sequences at the ends of eukaryotic chromosomal DNA molecules. Act as a buffer, non-coded, not important. |
|
|
Term
| Do Telomeres prevent the shortening of DNA? |
|
Definition
| no. but hey postphone the erosion of genes near the ends of DNA molecules. Shortening of telomers is connected to aging. |
|
|
Term
|
Definition
| proteins responsible for the first level of DNA packing in chromatin |
|
|
Term
|
Definition
| process by which DNA directs protein synthesis, includes 2 stages: transcription and translation |
|
|
Term
|
Definition
| synthesis of RNA using information in DNA; produces messenger RNA (mRNA) |
|
|
Term
|
Definition
| synthesis of a polypeptide, using information in the mRNA; happens in ribosomes. |
|
|
Term
| Cellular Chain of Command: |
|
Definition
DNA->RNA->Protein
20 amino acids, 4 neucleotide bases in DNA. |
|
|
Term
|
Definition
| series of nonoverlapping, 3-nucleotide "words". read in the 5' to 3' direction. |
|
|
Term
|
Definition
| provides a template for ordering the sequence of complementary nucleotides in an RNA transcript. |
|
|
Term
| How many Codons are there? |
|
Definition
| 64 codons. 61 code for amino acids and 3 are stop signals that end translation. |
|
|
Term
|
Definition
| catalyzes RNA synthesis. Pries a part and hooks together the RNA nucleotides. |
|
|
Term
| 3 Stages of Transcription |
|
Definition
1. initiation
2. elongation
3. termination |
|
|
Term
| Transcription: Initiation |
|
Definition
| Promoter: DNA sequence where transcription is initiated by the binding of transcription factors. |
|
|
Term
|
Definition
| mediate the binding of RNA polymerase |
|
|
Term
| Transcription: Elongation |
|
Definition
| RNA polymerase untwists the double helix and adds nucleotides to the 3' end of the growing RNA molecule. |
|
|
Term
| Transcription: Termination |
|
Definition
| Terminator RNA sequence is transcribed, causing the polymerase to detach and release the transcript |
|
|
Term
|
Definition
| transfers mRNA message to protein and transfers amino acids to the growing polypeptide in a ribosome |
|
|
Term
| What are the 4 binding sites on each ribosome for? |
|
Definition
| 3 binding sights for tRNA and 1 binding site for mRNA. |
|
|
Term
|
Definition
1. initiation
2. elongation
3. termination |
|
|
Term
|
Definition
| small ribosomal subunit binds to a molecule of mRNA and locates the start codon, where an initiator tRNA base-pairs (P site). Large subunit completes the initiation complex. |
|
|
Term
|
Definition
| amino acids are added one at a time, mediated by proteins |
|
|
Term
|
Definition
| stop codon is reached on mRNA, the A site of the ribosome accepts a "release factor" freeing the polypeptide from the ribosome. |
|
|
Term
| To Make a functional Protein (4): |
|
Definition
-coils and folding (primary structure)
-chemical modification (addition of sugards, lipids, etc)
-Removal of amino acids
-Broken into 2 or more pieces (ex insulin) |
|
|
Term
|
Definition
| changes in genetic material of a cell or virus |
|
|
Term
|
Definition
| production of an abnormal protein where incertion or deletion of nucleotides may alter the reading frame (things no longer line up) |
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Term
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Definition
| can occur during DNA replication, recombination or repair. |
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Term
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Definition
| physical or chemical agents that can cause mutations. ex. radiation |
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Term
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Definition
| was on Beagle voyage where he observed south american plants and animals. |
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Term
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Definition
inherited characteristics of organisms that enhance their survival and reproduction in specific environments
ex. beak variation in Galapagos finches |
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Term
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Definition
| process by which individuals with certain inherited traits are more likely to survive and reproduce. |
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Term
| Descent with Modification (3) |
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Definition
1. the unity of life
2. the diversity of life
3. the match between organisms and their environment |
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Term
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Definition
| human modification of other species by selecting and breeding individuals with desired traits |
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Term
| 2 Observations Darwin Made |
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Definition
1. individuals in a population vary in their heritable characteristics.
2. Organisms produce more offspring than the environment can support. |
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Term
| 2 Inferences that Darwin Made |
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Definition
1. Individuals that are well suited to their environment tend to leave more offspring than other individuals.
2. over time favorable traits accumulate in the population |
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Term
| 3 Key point of the Evolutionary theory |
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Definition
1. individuals do not evolve; populations do
2. NS can alter traits within a population only if there is variation in traits
3. NS depends on the context in which a species lives and mates (a trout that is favorable in the environment may be useless in another) |
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Term
| 4 Types of Data Used to Document Evolution |
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Definition
1. Direct observations of evolution.
2. Homology.
3. Fossil Record
4. Biogeography |
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Term
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Definition
similarity resulting from common ancestry-> related species have characteristics with an underlying similarity, even if they function differently.
Can be anatomical (homologous structures) and molecular. |
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Term
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Definition
How past organisms differed from present
extinction of species
evolutionary changes
origins of new groups of organisms
ex)fossil records of cetaceans (whales and dolphins) help explain how cetaceans originated from land mammals by documenting changes in limb structure |
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Term
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Definition
geographic distribution of species. we can study where species are found (currently and historically) to understand how species change over time in different environments.
ex) continental drift, island biogeography |
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Term
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Definition
| change in allele frequencies in a population over generations |
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Term
| 3 Mechanisms that causes allele frequency change: |
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Definition
1. Natural selection
2. Genetic drift
3. Gene flow |
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Term
| Discrete vs. Quantitative Basis |
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Definition
d= either or bases
q=variation along a continuum
Characters both discrete and quantitative contribute to variation within a population |
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Term
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Definition
measures the average percent of loci that are heterozygous in a population
gene variablility |
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Term
| Genetic Variation Can be measured as: |
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Definition
| Gene variability and Nucleotide Variability |
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Term
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Definition
| average heteroyzyosity measures the average percent of loci that are heterozygous in a population |
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Term
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Definition
| measured by comparing the DNA sequences of pairs of individuals |
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Term
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Definition
| differences between gene pools of separate populations |
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Term
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Definition
| graded change in a trait along a geographic axis |
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Term
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Definition
| localized group of individuals capable of interbreeding and producing fertile offspring |
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Term
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Definition
| consists of all alleles for all loci in a population |
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Term
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Definition
| if individuals in a population are homozygous for the same allele |
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Term
| Total # of Alleles at a locus = |
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Definition
| Total # of individuals X2 |
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Term
| Total # of Dominant Alleles at a locus= |
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Definition
2 alleles for each homozygous dominant individual + 1 allele for each heterozygous individual.
same logic applies for ressive alleles |
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Term
| Frequency of all alleles in a population will add up to 1 |
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Definition
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Term
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Definition
describes a population that is not evolving.
Frequencies of alleles and genotypes in a population remain constant from generation to generation. Allele frequencies will not change when gametes produce to the next generation randomly. |
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Term
| Probability that 2 Alleles will come together= |
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Definition
pxp
qxq
2pq
(pxp)+(qxq)+(2pq)=1 |
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Term
| 5 Conditions of Hardy-Weinberg Theorem |
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Definition
1. no mutations
2. random mating
3. no natural selection
4. extremely large population size
5. no gene flow |
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Term
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Definition
| the smaller a sample, the greater the chance of deviation from a predicted result |
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Term
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Definition
| describes how allele frequencies fluctuate unpredictably from one generation to the next. Tends to reduce variation through losses of alleles. |
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Term
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Definition
| A few individuals become isolated from a larger population. Allele frequencies may differ between populations. |
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Term
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Definition
| sudden reduction in population size due to a change in the environment. Reflecting gene pool may no longer be reflective of the original. |
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Term
| Summary of Genetic Drift (4) |
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Definition
1. significant in small populations
2. causes allele frequencies to change at random
3. lead to loss of genetic variation within populations
4. cause harmful alleles to become fixed |
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Term
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Definition
| consists of the movement of alleles among populations. Reduce variation among populations over time. |
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Term
| Natural Selection and Adaptive Evolution |
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Definition
| NS consistently causes AE by acting on an organisms phenotype. |
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Term
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Definition
| contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals. |
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Term
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Definition
| Directional, disruptive, stabilizing |
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Term
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Definition
| favors individuals at one end of the phenotypic range |
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Term
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Definition
| favors individuals at both extremes of the phenotypic range |
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Term
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Definition
| favors intermediate variants and acts against extreme phenotypes |
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Term
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Definition
| occurs as a match between an organism and its environment increases; because the environment can change, ae is a continuous process. |
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Term
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Definition
| genetic variation that does not confer a selective advantage or disadvantage |
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Term
| Diploidy (Preservation of Genetic Variation) |
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Definition
| maintains genetic variation in the form of hidden recessive alleles; heterozygotes can carry recessive alleles that are hidden from the effects of selection. |
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Term
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Definition
| occurs when NS maintains stable frequencies of 2 or more phenotyic forms in a population. |
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Term
| Balancing Selection Includes (2) |
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Definition
1. heterozygote Advantage
2. Frequency-dependent selection |
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Term
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Definition
| occurs when heterozygotes have a higher fitness then homozygotes |
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Term
| Frequency-Dependent Selection |
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Definition
| Fitness off a phenotype declines if it becomes too common |
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Term
| Why Doesn't Natural Selection result in "perfection" ? (4) |
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Definition
1. selection can act only on existing variations
2. Evolution is limited by historical constraints
3. Adaptations are often compromises
4. chance, Natural selection and the environment interact |
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Term
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Definition
| origin of new species, is at the focal point of evolutionary theory |
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Term
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Definition
| must explain how new species originate and how populations evolve |
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Term
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Definition
| consists of changes in allele frequency in a population over time |
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Term
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Definition
| refers to broad patterns of evolutionary change above the species level. |
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Term
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Definition
| compare morphology, physiology, biochemistry, and DNA |
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Term
| Biological Species Concept |
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Definition
| states that a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring; they do not breed successfully with other populations. |
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Term
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Definition
| the existence of biological factors (barriers) that impede two species from producing viable, fertile offspring. Classified by whether factors act before or after fertilization. |
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Term
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Definition
| offspring of crosses between different species |
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Term
| Prezygotic (definition and 3 reasons and examples) |
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Definition
barriers block fertilization from occurring by:
1. impeding different species from attempting to mate
2. Preventing the successful completion of mating
3. Hybrid breakdown
ex) habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, gametic isolation. |
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Term
| Pastzygotic (definition and 3 things) |
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Definition
barriers prevent the hybrid zygote from developing into a viable, fertile adult:
1. reduced hybrid viability
2. reduced hybrid fertility
3. hybrid breakdown |
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Term
| Limitations of Biological Species Concept (2&example) |
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Definition
-cannot be applied to fossils or asexual organisms (including prokaryotes)
-emphasizes absence of gene flow; however gene flow can occur between distinct species
ex) grizzly + polar bear = grolar bear |
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Term
| Morphological Species Concept |
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Definition
defines a species by structural features.
Applied to sexual and asexual species but relies on subjective criteria |
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Term
| Ecological Species Concept |
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Definition
views a species in terms of ecological niche.
Applies to sexual and asexual species and emphasizes the role of disruptive selection |
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Term
| Phylogenetic Species Concept |
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Definition
defines a species as the smallest group of individuals as a phylogenetic tree.
Applies to sexual and asexual species, but it can be difficult to determine the degree of difference required for separate species |
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Term
| 2 Way Speciation Can Occur: |
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Definition
Allopatric speciation
sympatric speciation |
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Term
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Definition
a population forms a new species while geographically isolated from its parent population.
-Gene flow is interrupted or reduced when a population is divided into geographically isolated subpopulations. |
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Term
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Definition
a subset of a population forms a new species without geographic separation .
-speciation takes place in geographically overlapping populations. |
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Term
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Definition
depends on the ability of a population to disperse
ex) canyon-barrier for small rodents, but not birds, coyotes or pollen.
-separate populations may evolve independently through mutations, NS and genetic drift
-regions with many geographical barriers typically have more species that do regions with fewer barriers. |
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Term
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Definition
may arise as a result of genetic divergence ex)mosquito fish in bahamas comprise seveal isolated populations in different ponds.
-Reproductive isolation between populations general increases as the distance between them increases |
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Term
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Definition
| extra sets of chromosomes due to accidents during cell division, may lead to sympatric speciation |
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Term
| sympatric speciation may result from (2) |
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Definition
-polyploidy
-appearance of new ecological niches
ex)north american maggot fly can live on native hawthorn trees as well as more recently introduced apple trees |
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Term
| Sexual Selection (sympatric speciation) |
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Definition
-NS for mating success
-can drive sympatric speciation
ex)sexual selection for mates of different clours has likely contributed to speciation in cichild fish in Lake Victoria |
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Term
| Speciation can be studied Using (3) |
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Definition
1. fossil records
2. morphological data
3. molecular data |
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Term
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Definition
describes periods of apparent stasis punctuated by sudden change.
Niles Eldredge and Stephen Jay Gould
The model contrasts with a model off gradual change in species existence. |
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Term
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Definition
can be rapid or slow.
Ranges from 4000 years (some cichlids) to 40 million years (some beetles) with an average off 6.5 million years. |
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