Chapter 4 Flashcards
Forces of Evolution
Origins of life
How the first living organism came into being
Phylogenies
The study of the evolutionary relationship between groups of organisms.
Phylogenetic tree of life
A family tree of all living organisms, based on genetic relationships
Last Universal Common Ancestor (LUCA)
A single celled organism that gave rise to the world and species we know today through its own cellular division.
Modern Synthesis
Integration of various signs of evolutional evidence to form a unified theory of evolution
What is a chromosome?
A career of collections of genetic information.
What is polymorphism?
Multiple forms of a trait; alternative phenotypes within a given species.
Define population
A group of individuals from the same species who are geographically near enough that they can breed and breed new generations of individuals.
Define genes
the basic unit of information that encodes the proteins needed to grow and function as a living organism.
Allele
A nonidentical DNA sequence found in the same gene location on a homologous chromosome, or gene copy that codes for the same trait but results in a different phenotype.
Gene pool
The entire collection of genetic material in a breeding community that can be passed from one generation to the next.
Homozygous genotype
When the two alleles are the same. ie XX, AA, BB
Heterozygous genotype
When the two alleles do not match. Aa, Bb, XY
What is evolution?
a change in the allele frequencies in a population over time.
What are allele frequencies?
Refer to the ratio or percentage of one allele in comparison to the other alleles for that gene within that study population.
Define genotype
The combination of two alleles that code for or are associated with the same genes.
Define mutation
Change to the genetic code
deleterious mutations
mutations associated with negative effects.
beneficial mutations
a change in the DNA that provides some beneficial advantage to a population at a a particular time.
UV crosslinking
UV rays interact with skin cells causing a mutation causing adjacent thymine bases to bond.
DNA repair mechanism
Mutations are corrected by enzymes that patrol and repair DNA in living cells .
Autosomal recessive
A phenotype produced by a gene on an autosomal chromosome that is expressed only in individuals homozygous fir the recessive allele.
Xeroderma pigmentosum
A disease which causes the repair mechanisms to not function properly resulting in a host of problems after sun exposure such as severe sun burn, dry skin, and heavy freckling.
Define somatic cells
the cells of our organs and other vital body tissues.
Gametes
reproductive cells
Spontaneous mutation
When a new mutation pops up at random in a family lineage.
Inherited mutation
When a spontaneous mutation is passed onto the offspring.
Define point mutation
A single letter change in genetic code resulting in the substitution of one nucleic acid base for a different one.
synonymous mutation
A mutation that does not change the resulting protein.
Nonsynonymous mutation
mutations which do cause a change in the protein. May change the resulting proteins amino acid sequence by altering the DNA sequence that encodes the mRNA or by changing how the mRNA is spliced prior to translation.
Insertions and deletions of indels
The addition or removal of one or more coding sequence letters. Entire codons may be added or removed if they are a multiple of 3.
Frameshift mutations
types of indels that involve the insertion or deletion of any number of nucleotides that is not a multiple of 3. Causes all codon beyond the mutation to be missed.
Transposable elements/transposons
Fragments of DNA that can jump around in the genome.
Retrotransposons
Transcribe from DNA to into RNA and then reverse transcribed to make a duplicate copy which can be copied into a new location in the DNA.