For your homologus traits provide the following information
(25 pts):
A.) Briefly
describe (NOT just identify) the two different species that possess the
homologus trait. (5 pts)
Humans are members of the Homosapien
Species. Needing oxygen to breath and capable to stay underwater for a short period
of time. Dolphins, are part of the whale family. There are 40 species of dolphins,
most live in shallow areas. Although, humans are dolphins are both mammals,
dolphins have separate holes for eating and breathing.
B.) Describe
the homologus trait of each species, focusing on the differences in structure
and function of the trait. Why do these homologus traits exhibit differences
between the two species? Make sure your explanation is clear and complete. (10
pts)
The arm of a human and the flipper
of a dolphin are homolgous structures. The human arm connects the body to the
hand and it’s the most used part of the body. The arms are composed of the
upper arm and forearm. The upper arm is considers from the shoulder to the
elbow and the forearm it’s from the elbow to the wrist. Instinctively, use our
arms for cover when in panic mode, or when we feel we are going to get hurt. The
front limbs are called flippers. The flipper is used for steering. The flipper
is often called a fin, it is also similarly structured to a human arm and hand.
Although, they are different and work
differently both are considered homologous structures because they have similar
anatomy.
C.) Who
was (generally, not specifically) the common ancestor of these two species and
how do you know that ancestor possessed this homologus trait? (5 pts)
As mentioned before the dolphin is part the whale family,
and human-beings are homo sapiens. Homology is "the existence of shared ancestry between a pari of structure, or genes, in different taxa." The structure of both species both come from the same tetrapod ancestral structure.
D.) Provide
an image of each species in this comparison. (5 pts)
2. For your analogous traits provide the following
information (25 pts):
A.) Briefly
describe the two different species that possess the analogous trait. (5 pts)
Penguins are a unique type of bird. They
know how to swim in water and can survive under water for long periods of time.
There are 18 species of penguins and can be found in different variety of
countries from Antarctica to the equator. Fish on the other hand are animals
that live in water, they have gills that helps them breathe. There are over
30,000 known fish species, and some can camouflage using the ocean floor.
B.) Describe the analogous trait of each species,
focusing on the similarities in structure and function of the trait. Clearly
explain why these analogous traits exhibit similarities between the two
species. (10 pts)
Both Penguins and Fish have similar fin
structures to help them navigate
under water. “However, because one is a bird and
one is a fish, it is clear that the fin evolved in these very different species
because it was the best functional feature for the environment they inhabit
instead of from a common ancestor” (Friedl)
Meaning
that there is no way that their ancestors were like that but they evolved over
time adapting to their environment.
C.) All
pairs of organisms share some common ancestor if you go back far enough in
time. Did the common ancestor of these two species possess this analogous
trait? Why or why not? (5 pts)
The penguins “basal ancestor, the first to separate from other
groups of birds, lived 71-68 million years ago, although this period can extend
to 40-100 million years” (Penguins Evolution).
Penguins changed over time and are the evolved results of an extinct
bird. Fish on the other hand have been around for millions of years and it is
said that fish have survived many climate changes and many mass extinctions. Fish
have adapted countless times. The fish we know today started looking that way
approximately 443-488 millions years ago. The first fish was in the Palaeozoic
Era, in the Devonian Period approximately 358-419 millions years ago.
D.) Provide
an image of each species in this comparison. (5 pts)
Friedl, Sarah. “Analogous Structures: Definition
& Examples.” Study.com, Study.com, 2003,
study.com/academy/lesson/analogous-structures-definition-examples-quiz.html#transcriptHeader.
“Penguin Evolution.” Edited by Pengiuns
World, Penguin Facts and Information, 2017, www.penguins-world.com/penguin-evolution/.
Homology: Good opening description of your species.
ReplyDeleteA little curious about your discussion on the homologous traits, making a couple of claims that need to be justified. First, is the arm really the "most used part of the body"? Is this really true? And how does this explain the differences in function and structure between the forelimbs of humans and dolphins?
Second, you seem to be arguing that the primary function of the forelimbs in humans is for protection. Is that true? It helps to understand the evolution of the human forelimb to explain this. Humans arose from quadrupedal primates, evolving bipedalism, and in the process, the forelimbs lost their locomotor function in favor of a manipulatory function. Part of this could well have been protective, but that wouldn't have been the primary function.
Beyond this, the dolphin flipper skeletal structure is short and broad, while the human forelimb structure is long and flexible. Can you explain these different structures in terms of their functions and the environments in which they evolved? Don't get distracted by minutia. Stay focused on the key points.
Your facts are correct for the ancestral section but how does that help us confirm that these traits are homologous? Focusing on "tetrapodal" structure is very broad. Can we narrow that down to just the forelimb?
Both humans and dolphins are mammals, so we know that the common ancestor would be an archaic mammal. We also know from the fossil record that early mammals possessed that generalized mammalian forelimb structure and passed that onto these two descendant species, with changes concurring over time due to differences in the environment (aquatic vs. terrestrial). That is what we need to know to confirm common genetic origin and confirm homology.
Analogy: Good opening description.
"Both Penguins and Fish have similar fin structures to help them navigate under water. “
Okay... but expand. This is the core of this prompt and needed to be explained fully.
"However, because one is a bird and one is a fish, it is clear that the fin evolved in these very different species because it was the best functional feature for the environment they inhabit instead of from a common ancestor"
You are jumping to ancestry here. Note that evolutionary distance (i.e., two different species) does not guarantee analogy. For example, the tiny bones we have in our inner ear are homologous with the gill branches in archaic fish. No kidding. So this is not a safe assumption. We need more information to confirm analogy.
Good information in your ancestry section but how does this confirm that these traits are analogous? You are close but you don't actually explain the evolution of the traits in question. That would address the issue. For example:
The common ancestor of the penguin and fish is an archaic fish, who did possess these fin structure and also passed that trait onto extant fish species. So the question is, did the penguin also inherit it's fin from that common ancestor? As you point out, penguins are birds, but let's take that information further to address this issue. Penguin "fins" are actually derived bird wings. Birds evolved wings when they split off of their reptilian ancestor, long after the split with ancient fish. This provides us with the evidence we need to confirm that this trait did evolve independently in at least one of these organisms, making these traits analogous.
Good images.
I really enjoyed reading this post. All of your information is well put and easy to read. I also used a dolphin in my analogous traits and its nice to see the same results. I didn't know that fish had survived for so long and through many extinctions. This is a really interesting post I learned a lot from it.
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