Homologous/Analogous Animals

1. a) Sharks and manta rays are homologous species that both have fins, gills, and scales.
    b) Fins:
            Shark fins are rigid, and fairly independent, structures protruding from their body that are made
            for speed. A manta ray's fins are completely attached to their body making them look like one
            solid fin that are made for cruising.
        Gills:
            Sharks most often have five gills slits that are used to collect oxygen from the water as it passes
            through them and transferred to throughout the body. A manta ray has five gill slits as well, but
            besides gathering oxygen, they are used to collect plankton and other organisms on gill rakers
            between the gill slats.
        Scales:
             Scales are a homologous trait between sharks and manta rays as well with both animals having
             placoid scales as their armor. A manta ray has a thicker coating on their skin, making them softer
             to the touch, but sharks feel like sand paper and have scales that turn or "bristle" to reduce drag
             in the water.
   c)A common ancestor of sharks and rays is hard, if not impossible because they belong to the phylum
      chondrichthyes (cartilaginous fish). Cartilage does not keep the way bone does making fossils and
      records virtually impossible to find - especially thousands and millions of years in the past.
   d)

   2. a) Sharks and whales can look very similar from far away, and both have fins, but they are
           analogous animals. Sharks have gills, a cartilage skeleton, scales, and a vertical tail fin. Whales
           have skin, horizontal tail fins, a skeleton of bone, and have to go to the surface for air.
       b) Fins:
                The fins of a shark are analogous to a whales because they do no move. Sharks mainly use
                their tails to swim where whales are more capable of moving their fins up down, side to side to
                act as a rudder. Also, a shark has a vertical tail fin that they move from side to side to swim
                through the water. A whale has a horizontal tail fin that moves up and down to propel them.
           Breathing:
                Sharks use gills to collect oxygen from the water whereas whales have an opening atop their
                head that closes to keep water out and hold their breath when they are under the water and
                opens when they come to the surface to breath.
           Skin:
                 Sharks have skin made of microscopic scales. It serves as body armor against other predators.
                 Whales have actual skin with glands and hair and all like all other mammals.
       c) When looking through cladograms, I noticed that sharks had become their own class and evolving
           independently from mammals millions of years before mammals even developed. With this
           information [about the only information I could find] I would say that a common ancestor of
           sharks and whales was some type of shark of fish.
       d)