Evo-Devo Flashcards
How many species of Galapagos finches are described from DNA phylogenies and fossil evidence?
18
What are the three hypotheses regarding the source of Darwin’s finches?
1) different inland species colonized on the island in separate events resulting in multiple species –> would expect greater relation between Darwin’s finches to mainland birds vs each other
2) one inland species colonized and radiated to become multiple species –> would expect a monophyletic relation (proven with evidence)
3) one species from Isla de Coco colonized and radiated –> Darwin’s finches should be more related to Isla de Coco birds than any other
What is the compound responsible for venom in snakes and how did it derive?
- crotamine
- modified defensins (antibacterial chemical)
- further mutations enhanced toxicity of crotamine
- variations in venom as a result of independent expression changes from pancreas to mouth
What is gene recruitment and what is an example?
duplication of a gene into a new regulatory system
i.e defensins in pancreas (antibacterial purpose) to crotamine in mouth (used for predation)
How does lactose intolerance work?
in absense of lactose, beta-gal is repressed and no more beta-gal can be transcribed
What are some examples of orthologous genes?
high expression of DPP (insects) and BMP2 (bats) = long limbs
What gene blocks hindlimb development in cetaceans?
Shh (sonic the hedgehog gene)
What genes are responsible for bilateral symmetry in flowers?
CYC and DICH
What are opsins and crystallins responsible for?
opsins (mutations of G-proteins) = light sensitivity
crystallins (exaption of anti clumping proteins) = light focusing
What is the difference between human and octopus eyes?
human retinas are ‘backwards’ = opsins are in the back of eye, creates a blindspot
Which gene is shared by bilaterians in eye development?
- PAX6
- mutations can cause blindness/loss of eyes
- gene is supressed in some species that live in no light environments (i.e cave fish)
Why do sticklebacks in smaller bog lakes not have any plates/spines?
- lack of fish/bird predators allowed energy to be redirected into other purposes
- invertebrate predators may use spines as grip when hunting young sticklebacks
What genes are responsible for changing Darwin’s finch beaks?
BMP4: more expression = wider beaks
calmodulin: more expression = longer beaks
How did the drought in 1977 affect Darwin’s finches?
- drought shifted dominant vegetation from soft seeded species to hard and large seeded plants
- beaks adapted for hard seed survived better and reproduced more
Why can two stickleback phenotypes coexist?
- first wave of marine sticklebacks evolved and had lower Eda due to low predation, kept to benthic zones
- second wave of marine sticklebacks kept high Eda, kept to limnetic zones
- both stickleback types occupy different niches
What is an extended phenotype?
phenotype that is separate from the individual but can be used to identify the species
i.e nests, webs
What pressures are on gall fly gall sizes?
too big = too attractive for bird predators to open up + eat larvae
too small = easier for parasitic wasps to inject their larvae to consume fly larvae
What is the phenomenon of recognizing faces in non-human objects?
pareidolia
What are the benefits of asexual and sexual reproduction?
asexual = greater proportion of population is reproductive and does not require fertilization to breed
sexual = greater genetic variation due to gamete combinations, can ditch deleterious mutations
How can species like rotifers be completely female/breed asexually and survive without large consequences?
they can incorporate foreign DNA to keep variation high
