Question

instructions: answer the following review questions for unit 3 in a complete sentence
unit 3 review questions
1 what is evolution, and how does it explain the diversity of life on earth?
2 describe charles darwins theory of natural selection and explain how it differs from lamarcks theory of acquired characteristics.
3 compare and contrast artificial selection and natural selection. provide an example of each process.
4 how do homologous structures, the fossil record, and molecular biology provide evidence for evolution? include specific examples in your response.
5 explain the process of speciation and describe how geographic and reproductive isolation can lead to the formation of new species.

Explanation:

1. Evolution is the change in the heritable characteristics of biological populations over successive generations. It explains life - diversity as different populations adapt to various environments through processes like natural selection, leading to the formation of new species.
2. Darwin's natural selection theory states that organisms with favorable traits are more likely to survive and reproduce. Lamarck's theory proposed that organisms acquire traits during their lifetime and pass them on. Darwin's is based on pre - existing variation, while Lamarck's on acquired changes.
3. Artificial selection is human - directed, like breeding dogs for specific traits. Natural selection is nature - driven, such as giraffes with longer necks surviving to eat high - hanging leaves.
4. Homologous structures (e.g., human arm and bat wing) show common ancestry. Fossil record (e.g., Archaeopteryx) shows transitional forms. Molecular biology (e.g., similar DNA sequences in different species) indicates relatedness.
5. Speciation is the formation of new species. Geographic isolation (e.g., squirrels separated by a canyon) can lead to different adaptations, and reproductive isolation (e.g., different mating calls) prevents interbreeding, resulting in new species.

Answer:

1. Evolution is the change in heritable characteristics of populations over generations and explains life - diversity through adaptation and speciation.
2. Darwin's natural selection is about survival of the fittest based on pre - existing variation; Lamarck's is about acquired traits being passed on.
3. Artificial selection: dog breeding; Natural selection: giraffe neck length evolution.
4. Homologous structures show common ancestry (human arm and bat wing), fossil record has transitional forms (Archaeopteryx), molecular biology has similar DNA sequences in related species.
5. Speciation is new species formation; geographic and reproductive isolation can lead to it by causing different adaptations and preventing interbreeding.