Biology 2485B Lecture Notes - Lecture 12: Lutein, Cerebellum, Pituitary Gland
17 Dec 2015
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Lecture 18 endocrinology 4: seasonality of mammalian breeding. Lepus americanus: long-day breeder short gestation, offspring need to grow enough to survive winter. Ovis aries: short-day breeder (offspring take advantage of fresh growth in spring) Animals take photoperiod and use it to determine seasonality in reproduction. Animals with faster lifestyles (i. e. hares) have short gestation periods but they need to be able to survive the winter so reproductive timing is such that it happens in the summer. Smaller animals tend to time their reproduction for the spring or summer except for when they don"t. Phodopus sungorus: long-day breeder semi-domesticated, easily wrangled in. Ovis aries: short-day breeder domesticated (with wild and feral counterparts), economically important. Between these two things they give us lots of information about reproductive physiology. Middle is a winter siberian hamster (white) Big morphological cycles in the coat colour, length and where they have fur. Darker in the summer, lighter in the winter.
