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Bio Terms Flashcards

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1
Q

Post-Zygotic

A

Isolation occurs when hybrids are formed but have reduced fitness

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2
Q

Pre-Zygotic

A

Isolation prevents the formation of hybrids in the first place

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3
Q

Gametic Isolation

A

The sperm and egg cannot unite to form a zygote

-protein or signal incompatibilities

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4
Q

Mechanical Isolation

A

The delivery of sperm to egg is impeded by physical barriers - male and female parts incompatible, different adaptations to specialized pollinators.

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5
Q

Temporal Isolation

A

Timing of mating differs so fertile females of one population do not encounter fertile males of the other - down/dusk, phases of the moon, spring/fall, flowering seasons of different hosts.

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6
Q

Behavioural Isolation

A

Behaviours, phenotypic traits including signals, differ so members of different populations do not recognize each other as mates - songs, pheromones, displays.

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7
Q

Habitat (ecological) Isolation

A

Populations differ sufficiently in ecology that they will not encounter each other as potential mates.

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8
Q

Reproductive Isolation

A

Result of many different changes in genetic compatibility that may lower fitness of hybrids or changes in phenotype that may provide a barrier to successful mating (or when differences become too great to allow mating)

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9
Q

Speciation

A

Is the process by which an existing population gives rise to a new population that no longer has potential to recombine with it as a single gene pool.

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10
Q

Microevolution

A

Change of allelic frequency in a population in a short period of time (Branch of a clade)

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11
Q

Geographic Isolation

A

Causes all gene flow to cease between sub-populations

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12
Q

Sympatric Speciation

A

Reproductive isolation occurs between two sup-groups of a singe population before divergence.

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13
Q

Allopatric Model

A

Reproductive isolation occurs between two sub-groups of a single population before divergence.

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14
Q

Autosomal

A

Is any of the numbered chromosomes, as opposed to sex chromosomes.

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15
Q

Allele

A

One of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

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16
Q

Chromosome

A

A structure in DNA wrapped around proteins

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17
Q

Chromatid

A

Each of the two threadlike strands into which a chromosome divides longitudinally during cell division. Each contains a double helix of DNA.

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18
Q

Chromatin

A

Partially coiled DNA (with histones). This is the normal state of the DNA when cell is not dividing (mitosis or meiosis)

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19
Q

Co-dominance

A

Both alleles are dominant

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20
Q

Complete Dominance

A

When there is a dominant and recessive allele [C^C]

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21
Q

Differentiation

A

Has instructions to make any type of cells, but depending on what type of cell it is, those instructions are turned on (i.e. nerve cells would use nerve cell instructions). Different set of proteins for different types of cells.

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22
Q

Diploid

A

Parent Cell that has 46 Chromosomes

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23
Q

Episstatic

A

The interaction of genes that are not alleles, in particular the suppression of the effect of one such gene by another.

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24
Q

DNA

A

(Deoxyribonucleic acid) is a very special molecule which carries information of species, and individual traits
Chromosome: Large bodies which are composed of one long strand DNA wrapped around proteins called histones and are supercoiled

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25
Dominant
a trait that will appear in the offspring if one of the parents contributes it.
26
Fertilization
The nuclei of the 2 cells join together in reproduction; make zygote
27
Gametes
Sex cell for organisms (Sperm, Egg); go through fertilization
28
Gene
Lengths of DNA that carry a code for the structure of proteins give us our characteristics.
29
Genotype
What combination of alleles
30
Haploid
Sex cell with half 23 chromosomes
31
Heterozygous
2 different alleles has a homozygous genotype (hybrid zygote)
32
Homologous Chromosomes
A copy of the same chromosome
33
Homozygous
2 identical alleles has a homozygous genotype (pure bread zygote)
34
Histone
The protein that chromosomes is wrapped around
35
Incomplete Dominance
Neither allele dominantes the other
36
Mitosis
Cell division to produce more cells: growth
37
Meiosis
Production of gametes or sex cells
38
Phenotype
The resulting trait (i.e. yellow)
39
Pure Breeding
A population that always produces that exact same characteristics
40
Recessive
can be carried in a person's genes without appearing in that person
41
Sister Chromatids
Replicated chromatids together
42
Synapsis
When homologous chromosomes come together to form a tetrad
43
Zygote
Formed by egg cell and sperm cell coming together, the sperm cell only gives the nucleus (Fertilizes egg)
44
Population
Group of individuals from the same species in a given area
45
Gene Pool
Total number of alleles at all gene loci in the population
46
Allelic Frequency
Proportion or percentage of a certain allele of a specific gene in the population
47
Genotypic Frequency
Frequency of a specific genotype in a population
48
Phenotypic Frequency
Frequency of a specific phenotype in a population
49
Macroevolution
Evolution over a long period of time. May lead to formation of new species (speciation) from a common ancestor
50
Hardy-Weinberg Equilibrium
Very large population - sampling errors could change the population if it were small No immigration or emigration - alleles cannot enter or leave No mutation - alleles do not change spontaneously No natural selection - no allele is favoured relative to any other allele Random mating - individuals have equal chances of mating with each other, so alleles get fully mixed
51
Genetic Drift
Sampling errors that occur when a population is small. In large populations, the next generation will usually be pretty representative of the alleles in the previous generation.In small populations one allele may get over represented or under represented or under represented by chance alone.
52
Mutation
Causes changes in the gene pool by creating new alleles
53
Gene Flow
Between populations (immigration) will generally tend to make the two populations more homogeneous. Since gene flow can change allelic structure
54
Assortative Mating
Where like chooses like, results in high levels of homozygosity
55
Disassortative mating
Tends to increase heterozygosity. While these forms of non-random mating do not lead to adaptive evolution themselves, they may expose alleles to natural selection in different ways.
56
Directional Selection
Leads to adaptation and change - classical Darwinian selection
57
Stabilizing Selection
Favours phenotypes closest to the mean and prevents change. May dominate when populations are well adapted, especially to a specialized niche, or when "normal" behaviour appearance or ritual is important to success.
58
Disruptive Selection
Favours the more extreme phenotypes over these close to the mean = should promote divergence into two sub - populations, but still controversial whether gene flow in the early stages would swamp differences.
59
Sexual Selection
Natural selection arising through preference by one sex for certain characteristics in individuals of the other sex.
60
Chromosomes
Large bodies which are composed of one long strand of DNA wrapped around proteins called histones and are supercoiled
61
Genes
Lengths of DNA that carry a code for the structure of proteins. These proteins give us our characteristics.
62
Interphase
Chromosomes replicate, energy stores are built up, proteins are produced
63
Prophase 1
Chromosomes coil become visible, each is visible as two chromatids, nucleus becomes less distinct, centrioles move to opposite poles and form the spindle
64
Late Prophase 1
Homologous chromosomes pair up, called synapsis, cross-overs between chromatids at locations called chiasma
65
Tetrad
Grouping of four chromatids that have similar genes when crossing over occurs
66
Anaphase 1
Homologous chromosomes are pulled apart. | - The sister chromatids remain attached
67
Telophase 1
Chromosomes come to lie at the poles
68
Prophase II (2)
Like Mitosis, but in two cells, cell prepares to divide again - New spindles are formed, the poles are at right angles to the original poles.
69
Metaphase II (2)
Chromosomes move to lie on the equator | -Spindle fibres attach to the sister chromatids via the kinetochore
70
Anaphase II (2)
Sister chromatids are pulled apart by the spindle fibres
71
Telophase II (2)
Chromatids collect at the poles - New nuclei form - The cell cytoplasm divides (cytokinesis) - Have daughter cells have half the original number of chromosomes (are haploid)
72
Spindle
A collection of minute fibres composed of microtubules, which are prominent during cell division, as mitotic spindle or mitotic apparatus.
73
True Pure Breeding
During pure breeding, a certain phenotypic trait passes down to offspring from the parent organism. A phenotypic trait is what people can see, such as hair colour and eye colour.
74
Cross Breeding
(Of an animal or plant) breed with a different breed, species, or variety.
75
Monohybrid Cross
Is a mating between two individuals with different alleles at one genetic locus of interest. The character(s) being studied in a monohybrid cross are governed by two or multiple alleles for a single locus.
76
Test Cross
Is used to determine if a group exhibiting a dominant trait is homozygous or heterozygous for that trait. More simply put, test crosses determine the genotype of an individual with a dominant phenotype.
77
Hybrid
The offspring of two plants or animals of different species or varieties, such as a mule (a hybrid of a donkey and a horse).
78
Dihybrid Cross
Is a punnet cross between two different lines (varieties, strains) that differ in two observed traits. In the Mendelian sense, between the alleles of both these loci there is a relationship of complete dominance - recessive.
79
Carrier
A genetic carrier (or just carrier), is a person or other organism that has inherited a recessive allele for a genetic trait or mutation but does not display that trait or show symptoms of the disease.
80
Epistatic Gene
The masking of the phenotypic effect of alleles at one gene by alleles of another gene. A gene is said to be epistatic when its presence suppresses the effect of a gene at another locus.
81
Loci
Location of allele on chromosome
82
Homogametic
XX Chromosome (Girl)
83
Heterogametic
XY Chromosome (Guy)
84
Sex Linked
(Of a gene or heritable characteristic) carried by a sex chromosome.
85
Sex Chromosomes
A chromosome involved with determining the sex of an organism, typically one of two kinds.
86
Handicap Principle
Suggests that males with elaborate displays actually show off the value of their genes, because they can demonstrate an ability to survive despite the handicap of their displays.
87
Sexy Son Hypothesis
Acknowledges that males could cheat by false advertising, but that false advertising can work as long as it produces another generation of females willing to fall for false advertising!
88
Species
make up actual or potential gene pools that do not exchange genes with other gene pools. (Most specific characteristics)

Biology(11) (2 decks)

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