homology vs. analogy divergent vs. convergent evolution & how they relate to
TRANSCRIPT
![Page 1: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/1.jpg)
Homology vs. Analogy
Divergent vs. Convergent Evolution
& how they relate to
![Page 2: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/2.jpg)
HOMOLOGOUS Structures
• homologytraits inherited by two different organisms from a common ancestor
![Page 3: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/3.jpg)
Example of Homology: the tetrapod limb
![Page 4: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/4.jpg)
The wing of a dragonfly and the wing of a butterfly are homologous — they were both inherited from an
ancient flying insect
![Page 5: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/5.jpg)
Not all homologies are obvious if they have been adapted for different roles. For example, the chomping
front teeth of a beaver look quite different than the tusks of an elephant. Each is a modification of the basic incisor
tooth structure
![Page 6: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/6.jpg)
Homologies are inherited from common ancestors. The octopus limb could only be homologous to the lizard limb
if they both inherited the limb from a common ancestor....But they didn’t......so just because an octopus and a lizard have a limb that helps them move does not
mean they are homologous.
![Page 7: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/7.jpg)
Homologies show that Divergent Evolution takes place
Divergent Evolution: A common ancestor evolves into new species, which continue to evolve and become less and less alike over time due to differences in the demands driven by the environment.
![Page 8: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/8.jpg)
![Page 9: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/9.jpg)
Brown Bears and Polar Bears illustrate divergent evolution. Scientists think that a long time ago a group of Brown Bears became geographically separated from the rest. This isolated group acquired new characteristics, such as the ability to eat meat, blubber to keep warm in snowy weather, and a white coat for camouflage. They slowly evolved into Polar Bears
![Page 10: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/10.jpg)
Adaptive Radiation is an example of Divergent evolution on a shorter, smaller time scale
Consider Darwin’s finches...each evolved a new beak to fill a wide range of ecological niches...or ADAPT.
![Page 11: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/11.jpg)
![Page 12: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/12.jpg)
![Page 13: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/13.jpg)
HINT......there must be a recent common ancestor involved if we are to claim that divergent evolution is taking
place, or that two features are homologous.
![Page 14: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/14.jpg)
So what about ANALOGY??
Consider the following example....
![Page 15: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/15.jpg)
Both are extinct animals and both of them have saberteeth...but are they homologous??
(Consider that Australia had separated from the Supercontinent a loooooong time ago)
Thylacosmilus, a marsupial mammal
Smilodon, the saber-toothed cat, which is a placental mammal
![Page 16: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/16.jpg)
![Page 17: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/17.jpg)
•analogysimilarity due to convergent evolution not common ancestry
CONVERGENT Evolution: When two separate groups of animals evolve to have similar structures
They are Analogous!
![Page 18: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/18.jpg)
How do analogies evolve?Often, two species face a similar problem or challenge. Evolution may then shape both of
them in similar ways — resulting in analogous structures.....like the saber teeth.
![Page 19: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/19.jpg)
As they weren't inherited from a common ancestor, the saberteeth in Smilodon and Thylacosmilus evolved independently from one another. That means that one
lineage on one part of the tree of life evolved saberteeth from normal length teeth, and a different lineage somewhere else on the tree also evolved saberteeth
from normal length teeth.
![Page 20: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/20.jpg)
Another good example of Analogous structures......
![Page 21: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/21.jpg)
While sugar gliders (marsupials) superficially resemble the placental
flying squirrels of North America, the ability to glide through the air evolved
independently in these unrelated mammals.
![Page 22: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/22.jpg)
So there you have it.....
HOMOLOGY vs. ANALOGY
![Page 23: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/23.jpg)
GAME TIME!Apply your knowledge.....
Homology or Analogy??
![Page 24: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/24.jpg)
skeleton made of cartilage skeleton made of bone
use gills to get oxygen from the water in which they swim
go to the surface and breathe atmospheric air in through their blowholes
don't nurse their young do nurse their young
don't have hair do have hair — they are born with hair around their "noses"
Dolphins and Sharks...... both have a streamlined body shape with a triangular fin on the back
![Page 25: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/25.jpg)
They are ANALAGOUS....
Sharks are closely related to rays, and dolphins are closely related to other mammals. Streamlined bodies and fins are traits that dolphins and sharks evolved separately, both as adaptations for swimming.
![Page 26: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/26.jpg)
![Page 27: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/27.jpg)
The leaves of an oak (left) and the leaves of a gingko (right)
![Page 28: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/28.jpg)
they were both inherited from a common ancestor with leaves.
They are homologous
![Page 29: Homology vs. Analogy Divergent vs. Convergent Evolution & how they relate to](https://reader036.vdocuments.site/reader036/viewer/2022062318/551a239c550346a4248b5077/html5/thumbnails/29.jpg)
Now it's your turn to study and prepare for your test on TUESDAY!!