Homologous Traits
Many animals throughout the animal kingdom have similar homologous structures. humans and bats derived from a common ancestor because they have the same bone structure, but is used for a different purpose.
As you can see the bat and the humans have the same bone structure. As humans we use our arms and hands to do pretty much everything. Bats have the same bone structure but use it to fly.
This tiny shrew like creature called the ancestral placental animal is the common ancestor between these mammals.
Analogous Traits
Many animals have similar structures but no common ancestor. They develop similar structures through evolution in their harsh climate. 
The analogous trait that is similar between these two species is their fins. They could not possess a common ancestor because their bone structures are not similar what so ever.
My only critique for your homology is the "humans use their arms for everything" line. Actually, it is important to recognize that we have essentially lost the locomotor function of our arms and hands. This will become important to remember in a couple of weeks. Good to compare this to bats who's forelimbs is mostly serving a locomotor function.
ReplyDeleteVery slim on the information for your analogous trait. Yes, fins of penguins and fish are analogous, but you need to explain why they possess similar traits. What selection pressures resulted in the evolution of these traits?
If you go back far enough, all organisms have a common ancestor. The question is, did this ancestor pass the trait in question onto both organisms? In this case, the common ancestor was an early fish and it did possess this trait and pass it on to later fish. But we also know that penguins developed their "fins" as derived bird wings, wings that developed during the split of birds from their ancestral reptiles, i.e., much longer after the split from the fish. In other words, these are indeed analogs, but that is the evidence you needed to confirm it.