Survival of the Fittest
This type of genetic change is the original source of new traits, such as a new fur color appearing in a population of animals.
Mutation
According to the law of superposition, these are the rock layers where you would expect to find the oldest fossils.
Bottom/Deepest Layers
This term describes structures with similar bone patterns (like a cat's leg and bat's wing) inherited from a common ancestor.
Homologous Structures
Comparing the sequences of this molecule is the most modern way to determine how closely related two species are.
DNA
This is the primary process that causes a population to change over time in response to its environment.
Evolution/Natural Selection
This term describes what happens to the "count" or percentage of a specific allele in a population over several generations.
Allele Frequency
This general term describes the total history of life on Earth documented by preserved remains in geologic strata.
Fossil Record
The tiny, non-functional hip bones found inside the bodies of modern whales are examples of this type of structure.
Vestigial Structures
If a human and a yeast cell share a large percentage of the same genetic code, it implies they evolved from this.
Common Ancestor
True or False: Scientists use fossils to determine the exact date and time a specific animal died millions of years ago.
False (Used for history of life)
If a dark environment makes light animals easier for hawks to see, the hawks are acting as this type of "factor."
Selection Factor
On a species abundance chart, this is indicated by the "width" of a group’s blackened area at any given point in time.
Number of Species
Finding a "remnant" pelvis in a legless whale suggests that the whale's ancestors were originally this type of animal.
4-legged land mammal
This is the most likely reason why two very different-looking organisms would have nearly identical DNA sequences.
Shared Ancestry
This term describes a species that is still living on Earth today, as opposed to one that is extinct.
Extant
This is the predictable outcome for a population if a helpful trait allows certain individuals to live longer and reproduce more.
Natural Selection
If a group of organisms on a diversity chart completely disappears and never reappears, they have experienced this.
Extinction
When two different species have identical bone arrangements in their limbs, it is evidence that they share one of these.
Common Ancestor
A scientist who specializes in finding and identifying fossils to help build these genetic "family trees" is called this.
Paleontologist
On your chart, the "Quaternary" period represents this in terms of geologic time.
Newest/Present Day
True or False: Natural selection can create a brand new trait out of thin air because an organism "needs" it.
False (Variation must already exist)
This geologic period on the Echinodermata chart showed a major drop in species for crinoids and blastoids.
Pennsylvanian
This is the main reason why a modern species can be alive today even if its "cousin" species went extinct millions of years ago.
Lineage splitting
This process describes how one ancestral group can split into two or more new, different species.
Speciation
Organisms such as Ammonites and Nautiloids are both members of this larger group of marine animals.
Cephalopods