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Questions and Answers
Fossil records indicate that whales evolved from land-dwelling mammals. Which of the following pieces of evidence best supports this evolutionary transition?
Fossil records indicate that whales evolved from land-dwelling mammals. Which of the following pieces of evidence best supports this evolutionary transition?
- The observation that whales and fish both live in aquatic environments.
- Similarities in the size and shape of whale and reptile skeletons.
- The presence of blowholes for breathing in modern whales.
- Vestigial structures, such as reduced pelvic bones, in whales. (correct)
Which evolutionary mechanism is most likely to lead to adaptive radiation?
Which evolutionary mechanism is most likely to lead to adaptive radiation?
- A mass extinction event creating many unoccupied niches. (correct)
- Gene flow between two populations in different environments.
- Stabilizing selection in a stable environment.
- Mutation rates decreasing in a population.
The discovery of Homo naledi in South Africa, a hominin species with a mix of primitive and modern features, contributes most directly to our understanding of:
The discovery of Homo naledi in South Africa, a hominin species with a mix of primitive and modern features, contributes most directly to our understanding of:
- The complex, branching nature of the human evolutionary tree. (correct)
- The exact geographic origin of *Homo sapiens*.
- The replacement of older hominin species by *Homo erectus*.
- The linear progression of human evolution from apes to humans.
Two species of frogs in the same geographic area have different mating calls. One breeds in early spring, and the other breeds in late summer. This is an example of which type of reproductive isolation?
Two species of frogs in the same geographic area have different mating calls. One breeds in early spring, and the other breeds in late summer. This is an example of which type of reproductive isolation?
Which postzygotic barrier leads to reduced hybrid fertility?
Which postzygotic barrier leads to reduced hybrid fertility?
What is the most likely outcome if two populations experience frequent gene flow?
What is the most likely outcome if two populations experience frequent gene flow?
The evolution of flight in birds and bats is an example of:
The evolution of flight in birds and bats is an example of:
A population of lizards is split by a newly formed canyon. Over time, the two populations diverge genetically and become reproductively isolated. This is an example of:
A population of lizards is split by a newly formed canyon. Over time, the two populations diverge genetically and become reproductively isolated. This is an example of:
In Lake Victoria, several closely related species of cichlid fish occupy different niches and have evolved different mating preferences within the same lake. This is an example of:
In Lake Victoria, several closely related species of cichlid fish occupy different niches and have evolved different mating preferences within the same lake. This is an example of:
Which of the following scenarios would most likely lead to sympatric speciation?
Which of the following scenarios would most likely lead to sympatric speciation?
Flashcards
Homologous Structures
Homologous Structures
Features in different species that are similar because of descent from a common ancestor.
Convergent Evolution
Convergent Evolution
The independent evolution of similar features in different lineages.
Vestigial Structures
Vestigial Structures
Structures of marginal, if any, importance to the organism. They are historical remnants of structures that had important functions in ancestors.
Adaptive Radiation
Adaptive Radiation
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Prezygotic Barrier
Prezygotic Barrier
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Postzygotic Barrier
Postzygotic Barrier
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Speciation
Speciation
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Allopatric Speciation
Allopatric Speciation
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Sympatric Speciation
Sympatric Speciation
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Phylogeny
Phylogeny
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Study Notes
Evidences of Evolution
- Evolution's evidence comes from fossil records, biogeography, comparative anatomy, and molecular biology.
- The fossil record shows the historical sequence of life's evolution.
- Biogeography studies species' geographic distribution, revealing how they evolved in different regions.
- Comparative anatomy looks at similarities and differences in the anatomy of different species.
- Molecular biology examines DNA and protein similarities, highlighting evolutionary relationships.
Types of Evolution
- Divergent evolution occurs when related species evolve different traits.
- Convergent evolution is when unrelated species evolve similar traits.
- Parallel evolution involves related species evolving similar traits independently.
- Coevolution happens when two species evolve together in response to each other.
Human Evolution
- Hominins evolved from primates.
- Key milestones: bipedalism, increased brain size, tool use, and language development.
- Early hominin genera: Australopithecus and Homo.
- Homo sapiens emerged about 300,000 years ago.
Prezygotic Barriers
- Prezygotic barriers prevent mating or block fertilization.
- Habitat isolation: species live in different habitats.
- Temporal isolation: species breed at different times.
- Behavioral isolation: species have different courtship rituals.
- Mechanical isolation: mating is physically impossible.
- Gametic isolation: eggs and sperm are incompatible.
Postzygotic Barriers
- Postzygotic barriers occur after hybrid zygotes form.
- Reduced hybrid viability: hybrids don't survive.
- Reduced hybrid fertility: hybrids are infertile.
- Hybrid breakdown: offspring of hybrids are weak or infertile.
Speciation
- Speciation is when new species arise.
- It requires reproductive isolation through pre or postzygotic barriers.
- Two main types: allopatric and sympatric speciation.
Allopatric Speciation
- Allopatric speciation occurs when populations are geographically isolated.
- Geographic barriers: mountain ranges, bodies of water.
- Genetic drift and natural selection cause divergence.
Sympatric Speciation
- Sympatric speciation occurs in the same geographic area.
- Mechanisms: polyploidy, sexual selection, and habitat differentiation.
- Polyploidy: extra sets of chromosomes.
- Sexual selection: mate choice drives divergence.
- Habitat differentiation: subgroups exploit different resources in the same habitat.
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