Analogy and Homology

1. HOMOLOGOUS TRAITS:
 
a. Whales and cats are are obviously very different animals. Whales are large aquatic mammals and come from the family of Cetaceans. Like all mammals, whales are warm blooded, have hair, have four-chambered hearts, and breathe air into lungs. Whales breathe through a blow hole above the water, which sets them apart from fish that breath underwater using their gills. Cats are also mammals, but they live on land and are from the family of Felines. Cats can be domesticated and are often used as pets, and just like whales cats are divided into many different types of species.

b.  These two animals are no where near close to each other in size and physically look nothing alike, but share homologous traits, which is the flipper of the whale and the leg of the cat.

 
 Although, the whale flipper and the cat leg both have a humerus, radius, ulna, carpels, metacarpals, and phalanges, they have significant differences in their structure and use of these traits. The bone structure of the cat tends to resemble more of the human structure, as opposed to the whale which has much longer phalanges that is used for swimming and traveling. The cat however, has a longer humerus and radius because it is used to stand on, and the phalanges of a cat are used for grabbing things, and also to defend themselves against other animals. 

c. All of these creatures, in their wondrous array of shapes and sizes, evolved from a small, unassuming, scurrying insect-eater that lived a few hundred thousand years after the apocalypse that finished off most of the dinosaurs. "Scientists have zeroed in on a tiny, rat-sized animal that they believe to be the common ancestor of many of today's modern mammals — including us. This furry little critter lived 66 million years ago, scurrying under the feet of big 'ol dinosaurs and subsisting primarily on a diet of insects."(1).

2. ANALOGOUS TRAITS:
a.  True flies belong to the order Diptera and include flies, gnats and mosquitoes. Flies often have transparent wings with few veins. They range in size from being nearly invisible to the naked eye to well over an inch in length. Moths, on the other hand, belong to the second largest insect order, Lepidoptera. They have two pairs of colored wings that are typically patterned, but drab in color. The smallest moth has a wingspan of less than 1/64-inch, while the largest moths have wingspans the size of a dinner plate.

b. Although both are flying insects, and can be major pests, that is where the similarity between a fly and a moth end. Both flies and moths have a complete metamorphosis including egg, larval, pupal and adult stages. The larval stage, in particular, is often different between the two types of insects. Fly larvae are legless, as opposed to moth caterpillars which have six legs and many leg-like appendages. Moths and flies also feed very differently. While there are many distinguishing characteristics between flies and moths, the wings are among the most conspicuous of the differences, but is also what makes them similar.

c."Knowing the characters of the organisms at the tips of a phylogeny lets you figure out what the ancestral characters were likely to have been. For example, modern flies and moths have silk glands but beetles and wasps don’t. The simplest explanation is that silk glands evolved only once in the ancestor of flies and moths. That means that when we imagine the most recent common ancestor of flies and moths (the ancestor at the node between them), we should imagine an insect with silk glands."(2) But the ancestor still shared the similar trait of having wings.

d.