Skip to main content

View Diary: The Daily Bucket: Unbearable cuteness of being a baby ground squirrel (88 comments)

Comment Preferences

  •  My guess would be (13+ / 0-)

    this species but this one is also a possibility.

    "To see both sides of a quarrel, is to judge without hate or alarm" - Richard Thompson

    by matching mole on Sat Jul 06, 2013 at 05:40:03 AM PDT

    [ Parent ]

    •  I can't really tell (12+ / 0-)

      Although I suspect that they were the latter, as I think I dug up some lizard eggs once.

      Bad day to be the earthworm in the tug of war.  And then it got dropped on its head? tail? but because of the other lizard, could not escape.

      www.tapestryofbronze.com

      by chloris creator on Sat Jul 06, 2013 at 06:04:22 AM PDT

      [ Parent ]

      •  except when they lay eggs...or not... (3+ / 0-)

        MM maybe can better unpack this quote for me:

        (viviparous lizard) The name of the species is derived from its ability to give birth to live young, an adaptation to a cool climate, but some southern populations are oviparous (egg-laying). The three to 10 young (or eggs) are usually produced in July. The blackish young measure about 3 cm (1.2 in), and when first born are surrounded by egg membrane, from which they break free after about a day. Males reach sexual maturity at two years old, females at three years old. Individuals from viviparous and oviparous populations may be hybridised, but with significant embryonic malformation.[4]
        cause how can 'some populations' have trouble with hybridizing ' but 'with significant embryonic malformation.'?

        This student is puzzled.

        Oh wait, it's summer, yer on vacation, nevermind :>

        This machine kills Fascists.

        by KenBee on Sat Jul 06, 2013 at 11:51:06 AM PDT

        [ Parent ]

        •  OK - here goes (4+ / 0-)

          First some background.  In vertebrates mode of reproduction can be split into three states.

          Oviparous - producing eggs in which embryonic development occurs outside of the mother.

          Ovoviviparous - offspring develop in eggs just as above but the eggs are held inside of the mother until they hatch.

          Viviparous - 'true' live birth - offspring develop inside the mother and are provided nutrition directly from mom during development (rather than indirectly through yolk)

          What is interesting about vertebrates is that some groups seem to be fixed in one mode while other groups have a lot of variation.  Mammals are all viviparous except for the platypus and echidna (which are distantly related to other mammals) while birds, crocodilians, and turtles are exclusively oviparous.  Amphibians  and bony fishes are mostly oviparous with some exceptions.  

          Three groups show a lot of variation in reproductive mode with ovoviviparity and viviparity appearing to have evolved multiple times within each.  These are the 'tooth carps' (fish such as guppies, mollies, topminnows, pupfish), the sharks and rays, and the snakes and lizards.  In the latter group live birth appears to be an adaptation to living a cold climate because by basking females can raise the temperature of embryos and speed their development.  Far northern or high elevation snakes and lizards are very commonly live bearers.

          Some groups like garter snakes are exclusively live bearers but others like the fence lizard genus Sceloporus are variable with live birth appearing to have evolved several times.

          This interesting case is one in which it appears that very closely related populations vary in mode of reproduction.  Individuals from different populations can mate with one another and sperm can fertilize eggs in these hybrid crosses.  However, presumably because of the difference in reproductive mode between populations, these hybrid embryos tend to not develop normally.

          "To see both sides of a quarrel, is to judge without hate or alarm" - Richard Thompson

          by matching mole on Sat Jul 06, 2013 at 12:26:08 PM PDT

          [ Parent ]

          •  amazing subtle variations and evolving muiltiple (4+ / 0-)

            times and in different genus as well, always amazing.

            So my question here is how can these be the same species yet have so much variation that hybrids aren't viable or healthy...I guess I don't know enough about the details of speciation to argue them at a post grad level..or even a way post grad level...grad being high school biology level, :>

            Thanks MM, always.

            This machine kills Fascists.

            by KenBee on Sat Jul 06, 2013 at 02:31:39 PM PDT

            [ Parent ]

            •  That's a good question (4+ / 0-)

              A lot of people would argue that they should be considered two species.  I don't know enough about this particular situation to knowledgeably comment but if hybrids have developmental problems and there is little or no mixing of genes between the populations then I would be inclined to consider them two different species.

              "To see both sides of a quarrel, is to judge without hate or alarm" - Richard Thompson

              by matching mole on Sat Jul 06, 2013 at 03:00:42 PM PDT

              [ Parent ]

Subscribe or Donate to support Daily Kos.

Click here for the mobile view of the site