Final Exam Studying Flashcards
Briefly describe the theory of descent with modification
Traits that are beneficial in a particular environment are passed along. This is due to random mutation, but the descent with modification itself is not random at all because the genetic variants that are beneficial are much more common than those that are not. Overtime variations become modified and change to make a species more efficient.
Briefly describe the theory of common descent
All species share a common ancestor. For example, a pterodactyl has a 5 fingered limb and humans have a 5 fingered hand, which suggests that even though both are different, they came from a common ancestor
Briefly describe two pieces of evidence presented for common ancestry/descent with modification
Fossils, biogeography, homology. Fossils-show that the earth is a lot older than we once thought, meaning that there were so many more species that came before us and we all have a common ancestor. 99% of the animals that used to exist are extinct, which shows how long everything has existed. In a rock, the deeper the layer the older the fossil/rock, and paleontologists have found many very old fossils that show similar structures and provide evidence for common ancestry/descent with modification
Homology- suggests a common ancestor because animals have homologous structures-similar structure, different function. Shows they come from common ancestor, but have modified to work in their own specific environment-like a whale’s tail and a bat’s wing are similar structures but different functions because of the different environments
Structures that are similar but with different functions. Like a human hand and bat wing
Homologous structures
Structures that are similar in function but are not inherited by a common ancestor. Like butterfly wing and bird wing
Analogous structures
What are the three primary tissue layers that form in the embryo, from which all other tissues develop?
Endoderm
Ectoderm
Mesoderm
Name the three types of muscle
Cardiac
Smooth
Skeletal
Skeletal and cardiac muscle are examples of ___ muscle
Striated muscle
In humans, the wrist is ___ to the shoulder
Distal
On a pig, snout is ___ to the tail
Cranial
What is the name of the book that Charles Darwin published in 1859 that introduced the theory of evolution via natural selection?
On the Origin of Species
Darwin’s theory on common descent, descent with modification, and natural selection hold up remarkably well today-but what was missing from Darwin’s theories that was not known at the time of the publication of his famous work?
At the time, Darwin did not know the role that DNA/genetics played into his theories. For instance, with descent with modification, mutations that occur are due to random rearrangement of DNA. Descent with modification is when the genetic variations that are most beneficial are passed along, making more efficient future generations.
How do analogous structures provide evidence for descent with modification/evolution?
They show how traits/structures are modified over time based on the environment. For instance, a butterfly wing and a bird wing are both wings, but they changed over time to adapt to their individual environments. A butterfly does not need the same kind of wing as a bird because it wouldn’t be useful in its particular environment. Analogous structures show that structures are modified based on unique environmental need.
A conifer is an example of a
Gymnosperm
Most mosses are examples of
Bryophytes
One of the defining features of all ___ is a protected ovary
Angiosperms
Name one of the phyla of tracheophytes that reproduce using spores
Lycopodium
