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54 Cards in this Set
- Front
- Back
What does fittest mean?
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-most intelligent
-strongest -most fertile --Having genes that are most suited to allow one to survive one's environment |
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One Cause of evolution?
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Differences in fitness.
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Selection
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Differences in fitness... variation in Number of offspring.
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Species
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A unit of classification.
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Darwin observed...
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IF: 1. there is variation 2. variation is heritable, 3. variants have differences in fitness.
THEN: Evolution (mutation) occurs. |
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Heritable sources of variations are...
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DNA--> mutation
SEX---> meiosis |
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Nucleotides
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Structural units of RNA and DNA.
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Protein
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A chain of Amino Acids.
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RNA and mRNA
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-Like DNA but with a "U" instead of a "T".
-Transcribed or copied information. |
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Genetic Code
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How to translate the message.
-Standard = 64 codons &20 Amino Acids |
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Chromosomes
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Packages of DNA
Organized structures of DNA proteins- found in cells. |
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Gene
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-Unit of heredity.
-Segment of DNA coding for protein or RNA and is at a specific location on a chromosome. |
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Mitosis
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nuclear division resulting in formation of genetically identical cells.
-asexual reproduction. |
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Meiosis
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Process of nuclear division resulting in Haploid cells.
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Haploid cells
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Genetically different cells.
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Homologous Chromosomes
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-same size and shape
-pair up during meiosis - have some genes but not always the same alleles, (AA, Aa) |
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Tetrad
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A Pair of homologous chromosomes.
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Allele
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Form of a gene.
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Locus
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location on a chromosome.
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Diploid cell
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Has 2 copies of each chromosome.
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Phenotype
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Appearance and behavior
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Genotype
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Specific forms of genes or alleles.
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Evolution
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Change in genetic composition of a population.
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P&Q-
P or Qsquared- 2PQ- |
-Frequency of dominant and recessive allele
-Frequency of paired (genotype) individuals (AA,aa) -Frequency of heterozygous allele (A,a) |
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Genetic composition
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Allele and Genotype frequencies.
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Gene Pool
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All alleles in a population.
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Hardy Weinberg Assumptions
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You can predict the proportion of alleles and genotypes in the next generation it there is:
1)No mutation 2)No migration 3)No selection 4)Large population 5)Random mating |
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Altruism
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1) Some individuals sacrifice their lives defending others
2) some individuals work for other's and do not reproduce. |
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Natural selection causes evolution IF:
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1) traits vary
2)traits heritable 3)traits effect fitness -Traits conferring higher Reproductive success to individuals in frequency in population. |
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Haploidiploidy and Selfish Gene
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IF: Female mates and 50% of her genes are in her daughter
IF: Female works to help mom mate then 75% of her genes are in her sister, |
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Stabilizing Selection
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selecting against extremes and for intermediate,
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Disruptive Selection
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New population is established
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Non Random Mating
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Positive Assortative Mating:
-inbreeding -increases the frequency of homozygotes relative to heterozygotes. |
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Phylogeny
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Evolutionary history.
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Phylogenetics
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science of reconstructing evolutionary history.
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Science
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a way of knowing
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Cladogram
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Shape of tree with no scale for branch length.
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Phylogram
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Evolutionary family tree.
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Allopatric
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In different places
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Sympatric
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In same places
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Directional Selection
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selection against one extreme and for another.
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Genetic drift
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change in gene frequency due to chance.
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Divergence
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Populations can evolve in different directions.
Can result from: a. Selection- diff, place =diff. selective pressures. b.small population size. |
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Speciation
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-formation of new species
-sometimes divergent populations become new species. |
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Morphological Species Concept:
How to define SPECIES. |
A Species is a collection of individuals that share more than 1 observable trait, not present in other collections.
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Monophyletic
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A group including all decedents of a particular ancestor.
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Sexual Selection
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Differences in fitness due to ...?
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Natural Selection
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Differences in fitness due to differences in Survivorship and reproduction in particular environments.
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Prezygotic
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Before Fertilization
a.courtship b.mate choice c.traits preventing fertilization |
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Protozygotic
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After Fertilization
a. hybrid infertility b.hybrid invariability c. Polyploid-->new species |
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Inbreeding
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results in a deficit of heterozygotes
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small population size
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usually results in loss of genetic diversity.
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Transcription
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a process during which a molecule of messenger RNA is assembled.
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Codon
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a sequence of 3 nucleotides.
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