1500_21_Monotremata

1500_21_Monotremata - BIO1500 W07 Montremata

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Unformatted text preview: BIO1500 W07 Montremata http://en.wikipedia.org/wiki/Image:Australian_1999_20_cent_piece.jpg PLACENTALIA: molecular view Springer et al 2004 MONOTREMATA: basic traits 1. Egg laying mammals 2. Possess traits of most mammals like fur, mammary glands, endotherm with high metabolic rate 3. Major difference to other mammmals is cloaca which constitutes the single endpoint of urinary, genital and anal duct. In Marsupilalia and Placentalia, these ducts terminate into discrete endings. 4. Long lived 5. Low repoductive rate 6. Long offfspring care 7. Bones in shoulder girdle that are not present in other mammals 8. Reptile like gate MONOTREMATA: classification 1. Platypus (1 species) 2. Tachyglossidae or echidnas or “spiny anteaters” (3 Tachyglossidae species) MONOTREMATA: Tachyglossidae (echidnas) Two extant genera: !Zaglossus (3 species), long snouted, New Guinea, insectivore !Tachyglossis (1 species), short snouted, common in New Guinea and Australia, feeds on termites and ants Tachyglossus aculeatus http://www.skullsunlimited.com/echidna.htm MONOTREMATA: Tachyglossidae (echidnas) Two extant genera: !Zaglossus (3 species), long snouted, New Guinea, insectivore !Tachyglossis (1 species), short snouted, common in New Guinea and Australia, feeds on termites and ants http://en.wikipedia.org/wiki/Image:LongbeakedEchidna.jpg Short-beaked Echidna Tachyglossus aculeatus http://en.wikipedia.org/wiki/Tachyglossidae TACHYGLOSSIDAE: basic traits !Spiny skin cover !Snouts function as nose and mouth !Jaw toothless and mouth small !Dig up termite or and hills and harvest insects with sticky tongue !Legs short and stout !Eggs are deposited into pouch !“Puggle” feeds ~45 days on milk patches of the female !Young animals are transferred into nursery burrows where they remain for another 7 months before getting weaned off http://www.shoarns.com/Echidna.htm Curled up Tachyglossus http://en.wikipedia.org/wiki/Image:Echidna%2C_Exmouth.jpg Tachyglossus feeding on termites Tachyglossus http://www.shoarns.com/Echidna.htm PLATYPUS: some basic traits 1 . Semiaquatic 2. Endemic to Australia and Tasmania 3. Egg laying 4. Predominantly nocturnal 5. Can reach up to 17 years http://en.wikipedia.org/wiki/Image:Platypus_skeleton_Pengo.jpg PLATYPUS: some basic traits 1. Air trapping fur for insulation http://en.wikipedia.org/wiki/Image:Platypus.jpg PLATYPUS: some basic traits 2. Tail functions as fat reserve http://en.wikipedia.org/wiki/Image:Platypus.jpg PLATYPUS: details 3. Webbed feet. Swims through propulsion with fore-feet. http://en.wikipedia.org/wiki/Image:Platypus.jpg PLATYPUS: details 4. Snout sports a duck shaped, leather skinned sense organ which is equipped with sensitive mechano- and electroreceptors. Platypus sorts floor of streams for small invertebrates. Electroreceptors in the duck bill hypothesized to play role in prey detection. http://www.drellenrudolph.com/featur eanimals/platypus.html PLATYPUS: behavior PLATYPUS: behavior PLATYPUS: details 5. Molars lost during late development and replaced with keratinised pads Ornithorhynchus anatinus, Duckbill Platypus, juvenile http://digimorph.org/specimens/Ornithorhynchus_anatinus/juvenile/index.phtml PLATYPUS: details 5. Molars lost during late development and replaced with keratinised pads Ornithorhynchus anatinus, Duckbill Platypus, adult http://www.digimorph.org/specimens/Ornithorhynchus_anatinus/adult/ PLATYPUS: details 6. Males produce unique venom which is delivered through calcareous hind leg spurs. Very painful but not lethal humans. http://en.wikipedia.org/wiki/Image:Platypus_spur.JPG PLATYPUS: details 7. 3-4 eggs are laid per reproductive cycle. Young animals are fed with mild for up to four months in feeding burrow. http://www.sheppardsoftware.com/content/animals/images/mammals/platypus_eggs.jpg PLATYPUS: details 8. Genetic determination of sex regulated by 10 sex chromosomes. Male sex has five 10 Y and five X chromosomes. Sex chromosome evolution in vertebrates. Homology between genomes of representative species are indicated by different colours and SRY/SOX3 and DMRT1 are tracked in each species. Homologues of the reptile/bird ZW pair are indicated in green, homologues of the ancient X chromosome shared by marsupials and placentals (XCR/YCR) are blue and homologues of the autosome that was added to the X and Y (XAR/YAR) are red. Grey regions of the Y chromosomes represents heterochromatin. Sex determination systems in snakes, lizards, amphibians and fish: female heterogamety (ZW), male heterogamety (XY) and temperature dependent sex determination (TSD) [Waters et al 2007]. PLATYPUS: details 9. Platypus lack mammalian sex determination genes (SRY-genes) but one of the X chromosomes features gene arrangement only known in bird sex chromosomes. Sex chromosome evolution in vertebrates. Homology between genomes of representative species are indicated by different colours and SRY/SOX3 and DMRT1 are tracked in each species. Homologues of the reptile/bird ZW pair are indicated in green, homologues of the ancient X chromosome shared by marsupials and placentals (XCR/YCR) are blue and homologues of the autosome that was added to the X and Y (XAR/YAR) are red. Grey regions of the Y chromosomes represents heterochromatin. Sex determination systems in snakes, lizards, amphibians and fish: female heterogamety (ZW), male heterogamety (XY) and temperature dependent sex determination (TSD) [Waters et al 2007]. PLACENTALIA: molecular view Springer et al 2004 ...
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