Midterm 1? Flashcards
Hadeon Eon
4.55 to 3.8 bya
Archaeon Eon
3.8 to 2.5 bya
Archaeon Eon
Earliest forms of unicellular life.
Proterozoic Eon
2.5 bya to 500 mya
Phanerozoic Eon
500 mya to present
Fossils of oldest trackways
480 mya
Oldest land plant fossil
475 mya
Oldest land vertebrates
360 mya
Dinosaurs (roar)
230 mya
Common mammalian ancestors
180 mya
Birds
150 mya
Ediacaran fauna
575 mya
Ediacaran fauna
Small animals with simple morphology.
Sponges, jellies.
Cambrian
~550 mya
Synapomorphy
Shared, derived trait.
Trait present in more than one in group
Symplesiomorphy
Shared, ancestral trait.
Trait present in in-group and out-group.
Autapomorphy
Derived trait found only in one taxa
Homoplasy
State that are present in more than one taxon BUT arose independently.
Same as convergent evolution.
Wings of birds and bats
Homology
Character state that is present in more than one taxon and arose from a common ancestor.
Parsimony
The best option is always the simplest one
Monophyletic taxa
Contain all descendents of a common ancestor and no other.
Paraphyletic taxa
Contain some but not all descendants of a common ancestor. Missing some descendants
Polyphyletic taxa
Taxa that do not share a most recent common ancestor
Systematics
Scientific study of all kinds and diversity of organisms and all relationships among them
Taxonomy
Science of describing, naming, and classifying species of living and fossilized organisms.
Phylogenetics
Study of evolutionary relationships among organisms
Types
Designated example specimen(s) representing a species.
Used to determine if an unknown organism belongs to that species.
Holotype
A single designated specimen used as a “type”.
The “name bearer” reference point.
Common for fossils
Paratype
Collection of specimens used as a “type” for a species.
Museum collections (all them bugs)
Genotype
Genetic makeup of an organism
Phenotype
Physical manifestation of genetic makeup
Law of dominance
Dominant allele is expressed in heterozygote
Law of segregation
All alleles are equally represented in gametes.
One allele to one gamete, the other to the other
Law of independent assortment
Genes on different chromosomes assort independently.
Where one goes has no affect on where the other goes
Polyphenisms
More than one discrete trait can arise from a single genotype at a single locus. Due to influence of environment.
Polygenic inheritance
A single trait controlled by multiple genes.
Multiple genes all contributing to the same trait.
Phenotypic plasticity
The same genotype can manifest as different phenotypes depending on the environment and can change in a life time.
Continuous variation
Phenotypic variation exists on a spectrum.
Ex. Human height.
Caused by polygenic inheritance.
Proteins
Machines of the cell and where variation allows selection.
Genes
A sequence of DNA that encodes a trait that can be selected for
Soma
Body cells
Germ cells
Sperm / egg
Redundancy
More than one codon encoding the same amino acid.
Ex. AGU and AGC both code for Serine.
Allows mutational tolerance.
Most of redundancy is at the 3rd position of the codon.
Genome
All an organisms DNA
Psuedogenes
Genes that have mutated such that they no longer contain a promoter.
Point of meiosis
Generate genetic variation
Generate haploid gametes
Crossing over
Physical exchange of DNA between pairs of chromosomes
Random fertilization
All sperm are different (and eggs)
Sperm that fertilizes isn’t necessarily the strongest.
Transition
Point mutation where purine substitutes with a purine or pyrimidine with pyrimidine.
(A/G —> A/G) or (C/T —> C/T)
Transversions
Point mutation where a pyrimidine substitutes with a purine or vice versa
(A/G —> C/T) or (C/T—> A/G)
Synonymous
Point mutation that has no effect on the amino acid sequence of a protein.
AKA silent mutation.
Mutation tolerance due to redundancy in genetic code
Non-synonymous
Point mutation where there’s a change in the amino acid sequence.
Can be missense or nonsense.
Missense mutation
Encode the wrong amino acid.
May affect the structure and function of a protein
Nonsense mutation
Creates a premature stop codon and a truncated protein.
Will affect the structure, may affect the function of a protein.
Aneuploidy
Unbalanced number of chromosomes in a set.
Ex. 2n+1.
Polyploidy
Duplication of entire genome.
Multiples of n
Autopolyploid
Genome duplication within the same species
Allopolyploid
Genome duplication due to hybridization between 2 species.
