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Lecture 21

BIOL 1902 Lecture Notes - Lecture 21: Marsupial, Blastocyst, Bluegill

Course Code
BIOL 1902
Michael Runtz

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Lecture # 21
Parental Care - Getting progeny off to a good start in life
Choosing the right habitat: (amphibians, frogs, turtles, insects not usually guarded eggs)
- American toad eggs
- Dragonflies: choose right slow moving water for eggs
- Temporary or Ephemeral ponds: good for laying eggs for frogs (freeze tolerant)
- Snakes: rotting logs moisture, protection
- Butterflies: milkweed leaves so that baby caterpillars can eat it
- Turtles: dig holes, lay eggs in, cover hole up again
o Soil temperatures during egg incubation determines the sex (global warming issues)
Protection of eggs: guarding
- Walking sticks: lay eggs that look like trillium seeds so ants take them underground (cap is edible)
o Ants protect them as they are a food source (cap)
Females -
- Snakes: Water and garter snakes hold eggs internally until hatched = ovoviviparity
- Skink: guard eggs after layed and cover with a special type of rocks
- Red back Salamander: rotting log moisture
- Wolf Spiders: carry egg sacs around = spiniris
- Nursery web spiders (dock spiders): guards the web with egg sac on them
- Some make fish (bass and bluegill sunfish)
- Giant waterbugs: females glue the eggs to males back
- Pregnancy (8 months) and protecting the young after born
o Feeding young
- Moose: 1 year after born protection (longer things live more protection given longer)
- 95% of all female mammals provide the care
- Foxes: Biparental care males bring food to female and pups
- Wolves: social animals, travel in packs Everyone takes care of the pups (summer home called
rendezvous sites: open sites. Popular sites are beaver meadows)
o Pups bite on adults corners of mouths to make them regurgitate food
o 1 Adult within howling earshot always to protect pups
Altricial = underdeveloped
- Bears: Altricial = cubs are very underdeveloped (females stay with cubs for 1.5 years)
o Mate in June, birth in January but pregnancy only 2 months = delayed implantation
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