Complex adaptations
phenotypic traits requiring multiple, specific mutations to yield a functional advantage. Snake venom is example of a complex adaptation
Gene control regions
an upstream section of DNA that includes the promoter region as well as other regulatory sequences that inluence the transcription of DNA
Promoter
a region of DNA upstream of a gene where relevant prteins bind to initiate transcription of that gene
Repressor
A protein that binds to a sequence of DNA or RNA and inhibits the expression of one or more genes
Transcription factor
a protein that binds to specific DNA sequences and acts like a light switch by turning all the sequences on or off simultaneously
Regulatory network
a system of interacting gnese, transcirption factors, promoters, RNA, and other molecules. Functions as a biological circuit, responding to signals with output that controls the activation of genese, during devlopment, the celll cycle, and the activation of metabolic pathways.
Homeotic transformations
one body part develops into another
Promiscuous proteins
can carry two functions; likely to take on new functions if duplicated
Paralog
a homologous gene that arises by gene duplication
Gene recruitment
co-option of a particular gene or network for a totally different function from mutation
ortholog
1 of 2 or mroe homologous genes separated by a speciation event
AER (apical ectodermal ridge)
stimulates distal growth of the limb bones in the mesodermal tissue
Pleiotropic effect
changin expression of a gene in a fish fin: simulataneously shring the outer area of the fin where fin rays develop and expanding the region where bond grows
crystallin
water-soluble structural protein found in the lens and the cornea of the eye accounting for the transparency of the structure
opsins
proteins that bind to light-reactive chemicals to underlie vision, phototaxis, circadian rhtyms, and other light-mediated resopnses of organisms
antagonistic pleiotropy
single gene affects expression of many traits
What do current giraffes have from tetrapod ancestors that demonstrate complex adaptations are not perfect
the recurrent laryngeal nerve in giraffe neck wraps loops around as if it is looping around gill arches
parallel evolution
independent evolution of similar traits in multiple lineages, all starting from a similar ancestral condition
Deep homology
when growth and development of traits in different lineages result from underlying mechanisms inherited from a common ancestor
In darwin’s finches, what did severe drought causing hardy woody seeds cause finches to evolve
Larger-beaked birds favored
Extended phenotype
a structure constructed by an organisms that can influence its performance or success (Gallflies lay eggs and create a gall for food and protection, beaver dam, bird nest)
Natural experiment
emperical study where individuals are exposed to the experimental and control conditions that are determined by nature or by other factors outside the control of the investigators
anadromous
live in seawater but breed in fresh or brackish water
Disadvantages of sex
twofold cost of sex- need two
search cost- locate another
reduced relatedness- half the genes of each
risk of STI
