BIOL 1902 Lecture Notes - Lecture 21: Marsupial, Blastocyst, Bluegill
Document Summary
Parental care - getting progeny off to a good start in life. Choosing the right habitat: (amphibians, frogs, turtles, insects not usually guarded eggs) Dragonflies: choose right slow moving water for eggs. Temporary or ephemeral ponds: good for laying eggs for frogs (freeze tolerant) Butterflies: milkweed leaves so that baby caterpillars can eat it. Turtles: dig holes, lay eggs in, cover hole up again: soil temperatures during egg incubation determines the sex (global warming issues) Walking sticks: lay eggs that look like trillium seeds so ants take them underground (cap is edible: ants protect them as they are a food source (cap) 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.