Chapter 15: Evidence Of Evolution Flashcards
(23 cards)
What is the definition of a fossil?
The preserved remains or impressions of once-living organisms.
What is the fossil record?
An assemblage of fossils arranged in order of age, which provides evidence of changes in species over time.
Who are paleontologists?
Scientists who study ancient life by means of the fossil record.
What is Tiktaalik known for?
A transitional fossil between fish and land-dwelling animals.
What does ‘descent with modification’ refer to?
The concept that all living things are related and that different species emerged over time due to natural selection.
True or False: The fossil record is a complete record of past life.
False.
What are intermediate fossils?
Fossils that show changes over time in a family of organisms.
How are fossils dated using relative dating?
Determining the age of a fossil from its position relative to layers of rock and fossils of known age.
What is radiometric dating?
The use of radioactive isotopes as a measure for determining the age of a rock or fossil.
What features make Tiktaalik a transitional fossil?
Possessed features of a lobe-finned fish, jointed elbow, wrist, and fingerlike bones.
What are tetrapods?
Vertebrates with four true limbs.
What is homology?
Similarity due to common ancestry.
What are homologous structures?
Structures that are similar because they are inherited from the same ancestor.
What is a vestigial structure?
Inherited from an ancestor and no longer serves a clear function in the organism that possesses it.
Fill in the blank: The genetic code is nearly identical among all _______.
organisms.
What is the significance of DNA in relation to evolution?
DNA can be used to determine how species are related.
What does the theory of evolution propose?
All living things share a common ancestor, and modern species arose from natural selection over millions of years.
What evidence supports the theory of evolution?
Fossil, anatomical, and DNA evidence.
What do younger fossils represent in the fossil record?
They are more similar to modern life than older fossils.
What adaptations are illustrated by transitional fossils like Pakicetus?
Adaptations for an aquatic life such as underwater hearing and reduced hindlimbs.
True or False: Closely related species have fewer DNA sequence differences than more distantly related species.
True.
What is the role of homologous genes among species?
They provide evidence of common ancestry.
How can DNA function as a molecular clock?
Closely related species show greater DNA sequence homology than do distantly related species.
