lecture 23 Flashcards
(17 cards)
phenotypic perspective on development
focus on morphs or phenotypic modifications to development
genetic perspective on developmental evolution
focuses on genes responsible for development. focuses more on individual mechanaisms
change in relative growth rate between ancestors and descendants (grows faster or slower)
allometry
no change in growth rate
isometry
changes in relative timing of developmental events (stop growing sooner or later)
heterochrony
gonads mature quickly quickly an adult looks like a juvenile in appearance compared to the ancestor
paedomorphosis
early maturation of the reproductive organs that shortens the growth period (heterochrony)
progenesis
slowed developmental rate of body relative to gonad development (body = slow, gonad = normal). (allometry)
neoteny
exaggeration of adult traits
peramorphasis
and extension of the growth period and adults appear overdeeloped (heterochrony)
hypermorphasis
faster growth rate of somatic development. faster body development and normal gonad development (allometric)
acceleration
positional regulatory genes that determine identity of body segments. small changes in these genes cause massive morphological changes
Hox genes
Hox genes are homologous and are conserved across species. They regulate the same components, just are expressed differently
deep homology
example of deep homology. regulate the number and type of vertebrae
segmentation/vertebral identity
example of deep homology. influence limb formations
limbs (sticky outies)
example of deep homology. induce eye development
Pax-6
example of deep homology. control floral organ formation
Apetalia
