Topic 13 Flashcards
body parts where they werent supposed to be or duplications
homeotic transformations
some of the first gene promoters to be explored
homeotic genes
ontogeny recapitulated phylogeny
biogenetic law
ontogeny:
Recapitulates:
Phylogeny:
:Development
:replays
:evolutionary history
development proceeds from general to specific
- an embryo can be anything
- to preserve early stages
Von Baer’s Law
changes in timing of development
Heterochrony
-2 forms
elder form- exageration of adult morphologies
-something added to life stage
Paramorphosis
Child form- retention of juvenile morphology
Paedomorphosis
Mature past adulthood and demonstrate hitherto unseen traits ( late offset)
Hypermorphosis
- thought irish elk
- different growth in our structures (head)
- acromegaly
Part grows faster than in ancestors
Acceleration
-narwhal tusk, fiddler crab, nectar spurs
onset of growth earlier
predisplacement
-ex/ meckels cartilage in birds
differential growth of structures
allometry-type of hypermorphism
beak on some birds
parts grow at same rate
isometry
early offset, growth halts early
progenesis
ex/salomanders w juvenile hands
aphids mature before wings form some fish
part grows slower than in ancestors
neoteny
-ex/humans increased skull allometry