PSYC 3201 Lecture Notes - Lecture 85: Neoteny, Canine Tooth, Altricial
12 Dec 2016
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Heterochrony
- A change in the timing of developmental events across evolution
- The appearance of traits occur at different points in development compared to ancestors
- Two types:
Neoteny: Slowing down in time of developmental events
Acceleration: speeding up of time of developmental events
Examples of Acceleration:
- Precocial development: speeding up of development compared to altricial animals
- Amnion: fluid-filled sac where the human embryo grows
- In primitive mammals: Embryo, then amnion
- In Humans: Amnion, then embryo
- Hyena newborns have canine teeth developing, this is very accelerated development
Examples of Neoteny:
- Newborn chimps have heads similar in shape to humas, but as they develop their head
becomes quite differently shaped
- Our toes are like ape toes when we are fetuses, but differentiate as we grow
- Infant cats and dogs have similar shaped skulls, but differentiate when older
- Kittens knead mother's belly for milk, but display this behavior when they are adults
- Extinct flightless Hawaiian goose called Thambetochen have wide angle between
scapula and coracoid and retain this angle through adulthood. Hatchlings of flying geese
also have this wide angle, but it becomes more acute as they develop into adults
- Orchestia have three forms:
1.) Intertidal
2.) Freshwater aquatic
3.) Terrestrial (most evolutionarily recent)
- Adult terrestrials retain juvenile characteristics of intertidal and freshwater like smaller
gnathopods (forelimbs) and fewer pleopods (hindlimbs) and translucent skin
- Some Salamanders retain their juvenile characteristics into adulthood like gills and flat
tails
- Aggression in rats: bred less aggressive and more aggressive rats → less aggressive
rats develop aggression more slowly, but eventually display almost as much aggression
s the high aggressive rats
find more resources at oneclass.com
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Document Summary
A change in the timing of developmental events across evolution. The appearance of traits occur at different points in development compared to ancestors. Neoteny: slowing down in time of developmental events. Acceleration: speeding up of time of developmental events. Precocial development: speeding up of development compared to altricial animals. Amnion: fluid-filled sac where the human embryo grows. Hyena newborns have canine teeth developing, this is very accelerated development. Newborn chimps have heads similar in shape to humas, but as they develop their head becomes quite differently shaped. Our toes are like ape toes when we are fetuses, but differentiate as we grow. Infant cats and dogs have similar shaped skulls, but differentiate when older. Kittens knead mother"s belly for milk, but display this behavior when they are adults. Extinct flightless hawaiian goose called thambetochen have wide angle between scapula and coracoid and retain this angle through adulthood.
