Presentation on theme: "EVOLUTION OF THE MAMMARY GLAND AND SECRETIONS"— Presentation transcript:
1EVOLUTION OF THE MAMMARY GLAND AND SECRETIONS Why is the mammary gland really a gland of reproduction?
2MAMMARY GLAND Gland of Reproduction Development is tied to hormones and physiology of reproduction.Purpose is to nuture young!!Huge female expenditure for something outside their own body!Develop offspring/ species survival!
3GIVE A 1 WORD DEFINITION FOR THIS COURSE! MAMMALS!
4MAMMALS mamma: latin word - breast / milk gland Kingdom: Animals Phylum: chordataSub phylum: vertebraeClass: mammalia> 4400 species ( good info on ~150)Evolved 250 million years ago (dinosaurs- 65)!
8SUBCLASS: PROTOTHERIA NO PLACENTAEgg laying mammalsLactation preceded placentation!One order: Monotremata3 species?Mammary glands: no teats!Tubules with myoepithelial tissueYoung have strong forepaws/ poorly developed hindlimbs
15METATHERIAGive birth to live young but not a true placenta: chorio-vitellineOne order: MarsupialsPouched animals3-4 week gestationEmbryo born w/ highly dev. forepawsAdaptation: animals move/ forage
16Young born and crawl up into pouch Why is > 3 important?Young born and crawl up into pouchLatches on teat for months (breathes!)Can have 2 in pouch, 1 latched, 1 notDifferent milk in each teat!
17Can have embryo in utero Lactation results in delayed growth Why is > 3 important?Can have embryo in uteroLactation results in delayed growthProlactin inhibits luteal function/ P4What a baby machine!!!
23* development and tissue FUTURE THOUGHTSWhat do mammals have in common:- hair- mammary glands* development and tissue* secretion products
24EUTHERIANWhat do boy and girl mammary glands have in common?
25AS 337 LACTATION BIOLOGY EXTRA CREDIT QUESTION 1 (10 PTS) Are the SUBCLASSES / orders we talked about in class (monotremes / marsupials/ 21 orders for eutherians) all there or are there some lost subclasses / orders looking for a home? Can you find a lost subclass / order and if so, state what it is and where you found it! (paper or website!) Or any other interesting evolution facts?DUE ON OR BEFORE CLASS NEXT THURS 1/23Can give to Mackenzie, Kali, Melissa, Brittany , or me in class or send via .HAVE A FANTASTIC WEEKEND!!!