Natural Selection and Adaptation
This phrase refers to the reproductive success of an organism, not how strong or long-lived it is.
What is evolutionary fitness
This term describes changes in allele frequencies in a population over generations.
What is microevolution
This species concept defines species as groups of organisms that can interbreed and produce fertile offspring.
What is the biological species concept?
The Earth is estimated to be this many years old.
What is 4.6 billion years?
These animals were the first vertebrates to evolve true jaws.
What are cartilaginous fishes (chondrichthyans)?
This process occurs when individuals with certain traits survive and reproduce more successfully.
What is natural selection
This condition of Hardy–Weinberg equilibrium is violated when individuals choose mates based on traits.
What is non-random mating
This form of speciation occurs when geographic barriers divide populations.
What is allopatric speciation?
This radiometric dating method is used for “recent” organic remains up to ~60,000 years old.
What is radiocarbon (C-14) dating?
These vertebrates are the only reptiles capable of powered flight.
What are birds
These traits increase an organism’s survival and reproduction in a specific environment, but may “go out of favor” if conditions change.
What are adaptations
This evolutionary mechanism is strongest in small populations and can cause alleles to become fixed or lost by chance.
What is genetic drift
Warblers feeding in different parts of the same tree illustrate this mechanism enabling sympatric speciation.
What is habitat partitioning
These layered structures formed by ancient cyanobacteria are among the oldest known fossils.
What are stromatolites?
Lobe-finned fishes are evolutionarily important because this major vertebrate group evolved from them.
What are tetrapods
This type of natural selection favors one extreme phenotype, shifting the population mean.
What is directional selection
This event occurs when a small group starts a new population with allele frequencies that do not represent the original population.
What is the founder effect
This prezygotic barrier prevents mating because species breed at different times of day or seasons.
What is temporal isolation
This experiment demonstrated that organic molecules can form under simulated early Earth conditions.
What is the Miller–Urey experiment?
This shared derived character allowed early amniotes to colonize dry land by protecting embryos from desiccation.
What is the amniotic egg
Peacocks evolving gigantic, colorful tails despite increased predation risk is an example of this evolutionary trade-off.
What is sexual selection competing with natural selection
This type of rapid speciation results from errors in meiosis that produce organisms with extra sets of chromosomes.
Polyploidy
Two species of birds are looking to mate. The male in the first species is calling to the female, but she doesn't respond. This is an example of
Behavioral isolation
This era, known as the “age of reptiles,” includes the dominance of dinosaurs.
What is the Mesozoic era?
This hallmark trait of hominins appears in the fossil record long before major increases in brain size, indicating that changes in locomotion—not cognition—were the earliest defining shift after their divergence from the chimpanzee lineage about 6 million years ago.
What is bipedalism