Bisc 102 vocab Flashcards
1
Q
Convergent evolution
A
The evolution of similar features in independent evolutionary lineages
2
Q
Fertilization/Syngamy
A
n+n->2n
3
Q
Natural selection
A
The differential survival and reproduction of variant individuals within a population
4
Q
Evolutionary fitness
A
The relative contribution each individual makes to the next and subsequent generations
5
Q
Gene pool
A
The aggregate of all copies of every type of allele at all loci in every individual in a population, / In a more restricted sense, the aggregate of all alleles for just one or a few loci in a population
6
Q
Heritability
A
The amount of phenotypic variation due to genotypic variation
7
Q
Phenotypic variation
A
From genotype and the environment, variation in physical, physiological or behavioural trait.
8
Q
Genome
A
The genetic material of an organism or virus; the complete complement of an organism’s or virus’s genes along with its noncoding nucleic acid sequences
9
Q
Phenotype
A
The observable physical and physiological traits of an organism, which are determined by its genetic makeup
10
Q
Episode of selection
A
Periods of strong selection pressure from a temporary environmental change or from a normal event in the life cycle of an organism
11
Q
Directional selection
A
Favours individuals exhibiting one extreme of a phenotypic range, thereby shifting a population’s frequency curve in one direction or the other
12
Q
Disruptive selection
A
Natural selection in which individuals on both extremes of a phenotypic range survive or reproduce more successfully than do individuals with intermediate phenotypes
13
Q
Stabilizing selection
A
Natural selection in which intermediate phenotypes survive or reproduce more successfully than do extreme phenotypes
14
Q
Selection differential
A
Measures the selection pressure on a trait and can be calculated for an episode of selection as the difference between the mean value of a trait before and after the episode of selection
15
Q
Sexual selection
A
A form of selection in which individuals with certain heritable traits are more successful in finding mates
16
Q
Replication
A
The repetition of a scientific experiment sufficient times to ensure that differences in the results from different treatments are meaningful and not due to change events
17
Q
The three condition that are necessary and sufficient for natural selection to produce evolutionary change in a given train in a population
A
- There must be phenotypic variation in the population; 2. The phenotypic variation within the population must have a heritable basis; 3. The heritable variation within the population must have fitness consequences
18
Q
Trophic level
A
The level in the different feeding relationships in an ecosystem which determine the route of energy flow and the pattern of chemical cycling
19
Q
Analogous
A
Having characteristics that are similar because of convergent evolution, not homology
20
Q
Ancestral
A
Traits that are shared by a group of related organisms and their ancestor
21
Q
Clade
A
A group of species that includes an ancestral species and all of its descendants
22
Q
Derived
A
Traits that are shared by a group of related organisms that are not seen in the ancestor
23
Q
Divergent evolution
A
The derivation of two or more lines of descent from a common ancestor, with the new derivatives becoming more dissimilar over time
24
Q
Homologous
A
Characteristics that are similar because of common ancestry
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Ingroup
A species whose evolutionary relationships we seek to determine
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Monophyletic taxon
Equivalent to a clade; a group of taxa that consists of a common ancestor and all of its descendants
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Outgroup
A species or a group of species from an evolutionary lineage that is known to have diverged before the lineage that contains the group being studied
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Phylogeny
The evolutionary history of a species or group of related species
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Phylogenetic tree
A branching diagram that represents a hypothesis about the evolutionary history of a group of organisms
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Paraphyletic group
A group of taxa that consists of a common ancestor and some, but not all, of its descendants
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Polyphyletic group
A group of taxa derived from two or more different ancestors
32
Rooted
A phylogentic tree that has at its base the common ancestor of all taxa shown on that tree
33
Genotype
The genetic makeup or set of alleles of an organism
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Phenotype
The observable physical and physiological traits of an organism which are determined by it's genetic makeup
35
Locus
A specific place along the length of the chromosome where a given gene is located
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Haploid
A cell containing only one set of chromosomes
37
Gene
A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA. In eukaryotes the gene includes regulatory sequences as well as the region encoding the protein/functional RNA itself. In bacteria and archaea, it is just the coding region because multiple protein-coding genes are encoded in one operon under the control of one set of regulatory elements.
38
Homologous chromosomes
A pair of chromosomes of the same length, centromere position and staining pattern that posses genes controlling for the same character at corresponding loci. One is inherited from each parent
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Allele
Any of the alternative versions of a gene that may produce distinguishable phenotypic effects
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Homozygous
Having two identical alleles for a given gene
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Heterozygous
Having two different alleles for a given gene
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Dominant
An allele that is fully expressed in the phenotype of a heterozygote
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Recessive
An allele whose phenotypic effect is not observed in a heterozygote
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Incomplete dominance
The situation in which the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele
45
Monohybrid cross
A cross between two organisms that are heterozygous for the character being followed (or the self pollination of a plant that is heterozygous for both characters)
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Dihybrid cross
A cross between two organisms that are each heterozygous for both of the characters being followed (or the self pollination of a plant that is heterozygous for both characters)
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Test cross
Breeding an organism of unknown genotype with a homozygous recessive individual to determine the unknown genotype. The ration of phenotypes in the offspring reveals the unknown genotype.
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Autosomal
A chromosome that is not directly involved in determining sex; not a sex chromosome
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Sex-linked
A gene located on either sex chromosome. Most sex linked genes are on the X chromosomes and show distinctive patterns of inheritance
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Polygenic ingeritance
An additive effect of two or more genes on a single phenotypic character
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Somatic cells
Any cell in a multicellular organism except a sperm or egg or their precursors; diploid; produced from diploid cell by mitosis
52
Gametes
A haploid reproductive cell such as an egg or a sperm; produced from diploid cell by meiosis (in animals, alternation of generation in plants)
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parthenogenesis
A form of asexual reproduction in which females produce offspring from unfertilized eggs
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fragmentation
A form of asexual reproduction whereby a single parent breaks into parts that regenerate into whole new individuals
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budding
A form of asexual reproduction in which outgrowths from the parent form and pinch off to live independently or else remain attached to eventually form extensive colonies
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vegetative propagation
Cloning of plants by asexual means
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Hermaphrodite
An individual that functions as both male and female in sexual reproduction by producing both sperm and eggs
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chromosome
A cellular structure carrying genetic material, found in the nucleus of eukaryotic cells. Each chromosome consists of one very long DNA molecule and associated proteins.
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Life cycle
the generation to generation sequence of stages in the reproductive history of an organism, from conception to production of its own offspring
60
centromere
In a duplicated chromosome, the region on each sister chromstid where they are most closely attached to each other by proteins that bind to specific DNA sequences; this close attachment causes a constriction in the condensed chromosome. (an uncondensed, unduplicated chromosome has a single centromere, identified by its DNA sequence).
61
sister chromatids
Two copies of a duplicated chromosome attached to each other by proteins at the centromere and, sometimes, along the arms. While joined, two sister chromatids make up on chromosome, and are eventually separated during mitosis or meiosis II.
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alternation of generation
A life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristic of plants and some algae.
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tetrad
A group of four closely associated chromatids of a homologous pair formed by synapsis (The pairing of homologous chromosomes during the meiotic phase of cell division)
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Meiosis
The type of cell division that reduces the number of sets of chromosomes from two to one in the gametes. In animals, this only occurs in germ cells, which are in the ovaries and testes.
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1. reductional division 2. equational devision
1. meiosis I because it halves the number of chromosome sets per cell (diploid to haploid) 2. meiosis II when the sister chromosomes separate.
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Chiasmata
The z-shaped microscopically visible region where crossing over has occurred in prophase I between homologous nonsister chromatids. Chiasmata become visible after synapsis ends, with the two homologs remaining associated due to sister chromatid cohesion
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Cohesin
Protein complexes that attach sister chromatids along their length- these are cleaved by enzymes during mitosis at the end of metaphse, and in two steps (anaphase I and II) during meiosis
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bdellloid rotiger
A group of microscopic animals (~400 spp) that live in a great variety of environments around the world. One of the only animals that reproduces exclusively asexually, and probably haven't engaged in sex in the 40 million years since their evolutionary origins- however, different mechanisms has evolved for these animals to generate genetic variation
69
heterozygote advantage
Grater reproductive success of heterozygous individuals compared with homozygotes; tends to preserve variation in a gene pool
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Pleiotropy
The ability of a single gene to have multiple effetcs ex. the gene that determines flower colour also affects the colour of the coating on the outer surface of the seed
71
Epistasis
A type of gene interaction in which the phenotypic expression of one gene alters that of another independently inherited gene ex. Labrador retrievers- pigment in fur colour is a separate gene than for black/brown colouration (which would give gold if both pigment alleles are recessive)
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Point mutation
Change in a single base pair, which changes a single amino acid
73
Gene duplication
A gene mutation caused by one or more extra sets of chromosomes, a condition known as polyploidy.
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Genome duplication
Extra copies of all chromosomes above the diploid level; Triploid, tetraploid; Common in plants
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Bottleneck effect
genetic drift that occurs when the size of a population ins reduced, as by a natural disaster or human actions. Typically, the surviving population is no longer genetically representative of the original population. ex. No allelic variation in 24 genes examined in the population of elephant seals
76
Founder effect
Genetic drift that occurs when a few indiciduals become isolated from a larger population and form a new population whose gene pool composition is not reflective of that of the original population. ex. Polydactyly in Amish people
77
Sexual dimorphism
Differenes between the secondary sex characteristics of males and females
78
Certainty of paternity
Relatively low in most species with internal fertilization if the female mates with someone other than her usual mate (increased by guarding female, removing sperm from female reproductive tract, introducing large quantities of sperm that displace the sperm of other male). Certainty is relatively high in species with external fertilization (such as fish) because mating and fertilization happens at the same time
79
Cognition
The process of retaining and acting upon sensory information; High cognitive function associated with problem solving and social learning
80
Learning
Process of acquiring new skills or knowledge through experience; Ability to adjust behaviour when exposed to novel circumstances
81
Evolution of Cognition
Selection for increased cognitive function balanced by energy costs associated with neural tissues; Unless higher cognitive abilities increase overall fitness substantially, they will not evolve
82
Polyploidy
A chromosomal alteration in which the organism possess more than two complete chromosome sets. It is the result of an accident of cell dicision
83
Prezygotic mechanisms
prevent mating or fertilisation
84
Postzygotic mechanisms
prevent zygote development or reproduction
85
Character
An observable heritable feature that may vary among individuals
86
Trait
One of two or more detectable variants in a genetic character
87
Hybridization
In genetics, the mating or crossbreeding of two true-breeding varieties
88
P/F1/F2 generations
The parent generation/The first filial hybrid (heterozygous) offspring arising from a parental cross/The offspring resulting from interbreeding (or self-pollination) of the hybrid F1 generation
89
Blending hypothesis
Explanation of heredity most widely in favour during the 1800's: genetic material contributed by two parents mixes like blue and yellow paint gives green. This would give rise to a uniform population over many generation. The reality, the passing of genes, is more like a deck of cards!
90
Quantitative and discrete characters
Characters that vary in gradations along a continuum, often from two or more genes (skin, height) vs. traits classified on an either-or basis, many determined by a single locus (Mendel's peas, purple or white)
91
Average heterozygosity
The average percentage of loci that are heterozygous ex. drosophila has 14% heterozygous, the rest of the genes are homozygous, so the average heterozygosity is 14%
92
Norm of reaction
The range of phenotypes produced by a single genotype, due to environmental influences ex. hydrangea flowers genetically coded for between blue-violet to pink, and the shade and intensity depends on the acidity and aluminum content of the soil
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Multifactorial
Referring to a phenotypic character that is influenced by multiple genes and environmental factors ex. skin
94
Geographic variation
Differences between the gene pools of geographically separate populations or population subgroups ex. mouse population with different chromosomes fused
95
Cline
A graded change in a character along a geographic axis ex. as water T gets colder, fish have more of a gene that allows them to swim faster
96
Fru genes
controls courtship behaviour in fruit flies, example of how a single gene controls so many behaviours
97
Vasopressin receptor
in male prairie vole, a single gene controls in the amount of vasopressin receptors in the brain which determines whether they associate closely with they mate or not
98
adaptive evolution
evolution that results in a better match between organisms and their environment
99
Habitat isolation
Two species that occupy different habitats within the same area may encounter each other rarely, if at all, even though they are not isolated by obvious physical barriers such as mountain ranges ex. garter snakes species, one in water one terrestrial
100
Reproductive isolation
Biological factors that impede members of two species from interbreeding and producing viable fertile offspring
101
Allee effect
Individuals may have a more difficult time surviving or reproducing if the population size is too small
102
Temporal isolation
Species that breed during different times of the day, different seasons, or different years cannot mix their gametes ex. skunks breed winter or summer
103
Behavioural isolation
Courtship rituals that attract mates and other behaviours unique to a species are effective reproductive barriers even between closely related species ex. benthic, limnetic sticklebacks
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Mechanical isolation
Mating is attempted but morphological differences prevent its successful completion ex. snails with shells spiraling in two different directions
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Gametic isolation
Sperm of one species may not be able to fertilize the eggs of another species, for a number of reasons such as not being able to survive in the female reproductive tract or biochemical mechanisms that prevent sperm from penetrating the membrane of another's egg ex. sea urchins
106
Reduced hybrid viability
The genes of different parent species may interact in ways that impair the hybrid's development or survival in its environment ex. most hybrid salamanders will not complete development
107
Reduced hybrid fertility
Sterile offspring ex. donkeys
108
Hybrid breakdown
First generation hybrids are viable and fertile, but when they mate with one another or with either parent species, the offspring of the next generation are sterile ex. cultivated rice
109
autopolyplod
an individual that has more than two chromosome sets that are all derived from a single species
110
allopolyploid
When sterile plant polyploid hybrids (reproduce asexually) change into fertile polyploid. The allopolyploids are fertile when mating with each other but cannot interbreed with either parent species
111
adaptive radiations
periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles ex. mammals become larger and diversifying after the disappearance of dinosaurs
112
paleoanthropology
the study of human origins
113
the oldest hominin
Sahelanthropus tchadensis
114
Homo floresiensis
dwarf hominin species from Indonesia; evidence suggests that they originated from a lineage that branched off from a hominin species that lived earlier than H. erectus and that their reduced brain size was selection pressure for reduced energy consumption
115
species richness
the number of different species in a community
116
species diversity
the variety of different kinds of organisms that make up the community
117
relative abundance
the proportion each species represents of all individuals in a community
118
invasive species
organisms that become established outside their native range
119
evapotranspiration
the evaporation of water from soil plus the transpiration of water from plants- a function of solar radiation, temperature, and water availability, much higher in the tropics, and correlates with diversity
120
Genetic diversity
The genetic variation within a population, and between populations, that is associated with adaptations to local conditions- loss of genetic diversity means less microevolution potential
121
Species diversity
the variety of species in an ecosystem or across the biosphere
122
Ecosystem diversity
the variety of ecosystems in the bioshpere
123
biophilia
our sense of connection to nature and all life
124
ecosystem services
all the processes through which natural ecosystems help sustain human life- purify air and water, detoxify and decompose wastes, reduce impacts of extreme weather and flooding
