Test one part two Flashcards
mRNA
a form of RNA that carries specifications for protein synthesis from DNA to ribosomes
tRNA
Form of RNA that facilitates protein synthesis by first binding to amino acids in the cytoplasm and then binding to the appropriate site on the messenger RNA molecule. There is at least one distinct form of tRNA for each amino acid.
codon
A sequence of three DNA basses on a DNA molecule that constitutes one word in the message used to create a specific protein. There are 64 codons.
Amino acid
A molecule that is linked in a chain to form a protein. There are 20 amino acids, all of which share the same molecular backbone but have a different side chain.
Nucleus
The distance part of the cell that contains the chromosomes. Eukaryotes (fungi, protozoans, plants, and animals) all have nucleated cells; prokaryotes (bacteria) do not.
fixation (in alleles)
the process where a specific variant of a gene (allele) becomes the only version present in a population,
sympatric speciation
the idea that speciation can happen with no geographic isolation and using only natural seelction. Species diverge to avoid competition for resources and develop different adaptations.
Allopatric speciation
speciation that occurs when two or more populations of a single species are geographically isolated from each other then diverge to form two or more new species.
allopatric ecological speciation
Subpopulations adapt to different environments, no longer want to mate with each other if reintroduced.
character displacement
The result of competition between two species that causes the members of different species to become morphologically or behaviorally more different from each other.
Parapatric speciation
A two step process of speciation in which 1) selection causes the differentiation of geographically separate, partially isolated populations of a species and 2) later the populations become reproductively isolated as a result of reinforcement.
adaptive radiation
The process in which a single lineage diversifies into several species, each characterized by distinctive adaptations. The diversification of the mammals at the beginning of the Cenozoic era is an example of an adaptive radiation.
phylogeny
The evolutionary relationships among a group of species usually diagrammed as a family tree
comparative method
A method for establishing the function of a phenotypic that by comparing species.
molecular clock
Hypothesis that genetic change occurs at a constant rate and thus can be used to measure the time that has elapsed since two species shared a common ancestor. The molecular clock is based on observed regularities in the rate of genetic change along different phylogenetic lines.
homology
Similarity between trans that is due to common ancestry not convergence. For example the reason that gorillas and baboons are both quadrupedal is that they are both descended from a quadrupedal ancestor
correlated response
the change observed in one trait when selection is applied to another trait, meaning that when you try to select for a specific characteristic in an organism, another, genetically linked trait may also change unintentionally due to the shared genetic basis between the two traits; essentially, selecting for one trait can lead to changes in a correlated trait as well
derived trait
A trait that appears later in the evolution of a lineage or clade. Derived traits are newly developed trait compared to those that are found farther back in the evolutionary tree
biological species concept
the concept of species as a group of organisms that have the potential to reproduce with one another and produce fertile offspring and that are reproductively isolated from other such groups. Adherents of the biological species concept believe that gene flow tends to maintain similarities among members of the same species and the lack of gene flow is necessary to maintain differences between closely related species.
ecological species concept
natural selection favors one of two extremes-> hybrid/intermediate forms at a disadvantage->natural selection eliminates hybrids-> species boundaries maintained without isolation. ACCOUNTS FOR SPECIES WHO DO INTERBREED.
evolutionary species concept
A single, monophyletic lineage evolving separately and maintaining its identity from other such lineages, with its own evolutionary tendencies and historical fact.
evolutionary species = biological species + time
evolutionary classification
a system in biology where organisms are grouped based on their evolutionary relationships, primarily considering shared ancestry and the degree of evolutionary change they have undergone, rather than just physical similarities
cladistic taxonomy
A system for classifying organisms in which patterns of descent are the only criteria used.
