Evolution and Origin of Life

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Questions and Answers

Explain how Darwin's theory of evolution differs from Lamarck's theory regarding the timing of when variations occur in relation to environmental change.

Darwin proposed variations occur randomly, primarily before environmental changes apply selective pressure, while Lamarck suggested variations arise after and in direct response to environmental changes.

What are some potential causes of reproductive isolation, and how does reproductive isolation contribute to speciation?

Behavioral, temporal, and geographic isolation can prevent interbreeding. By preventing gene flow between populations, reproductive isolation allows them to diverge genetically, potentially forming new species.

Describe the role of mutation and genetic shuffling as sources of genetic variation within a population. How do these processes influence the potential for evolutionary change?

Mutations introduce new alleles into a population, while genetic shuffling (crossing over, independent assortment, and sexual reproduction) recombines existing alleles into novel combinations. Both processes increase genetic variation, providing raw material for natural selection and evolutionary change.

How does the concept of 'survival of the fittest,' as it relates to natural selection, apply to the ability of an organism to reproduce and pass on its genes?

Survival of the fittest refers to an organism's ability to survive and reproduce. The organisms best adapted to their environment are more likely to survive and pass on their genes, thus contributing to the next generation. Signup and view all the answers

Explain how selective breeding demonstrates the power of artificial selection and its impact on variations within a species.

Selective breeding, where humans choose specific traits and breed organisms with those traits, demonstrates artificial selection. It shows how selecting for desired variations can dramatically alter a species over generations, leading to significant changes in a population's characteristics. Signup and view all the answers

How do homologous body structures provide evidence for evolution and common ancestry among different species?

Homologous structures are body parts in different species that have a similar underlying structure but may have different functions. The shared structure indicates a common ancestor from which these species inherited the basic design. Signup and view all the answers

How is relative frequency used when studying population genetics, and why is it usually expressed as a percentage?

Relative frequency measures how often an allele appears in a gene pool compared to other alleles for that gene. Expressing this as a percentage makes it easier to compare allele frequencies across different populations or over time. Signup and view all the answers

Describe the significance of the Miller-Urey experiment in understanding the origin of life on Earth, especially in terms of the production of organic molecules.

The Miller-Urey experiment demonstrated that complex organic molecules, such as amino acids (the building blocks of proteins), could spontaneously form from inorganic gases under conditions thought to simulate early Earth's atmosphere. Signup and view all the answers

Explain how the presence of vestigial organs in modern species supports the theory of evolution.

Vestigial organs are structures that have lost their original function over evolutionary time. Their presence suggests that the species evolved from ancestors in which these organs were functional, providing evidence of evolutionary change. Signup and view all the answers

What is the role of the ozone layer in relation to the evolution of life on Earth, and where is it located?

The ozone layer, located 10-15 miles above the Earth's surface, blocks harmful ultraviolet (UV) radiation from the sun. Its formation allowed life to move from the oceans to land by protecting organisms from UV damage. Signup and view all the answers

Flashcards

Survival of The Fittest

The best adapted organisms survive and reproduce, while the least adapted may not reproduce and may die sooner.

Theory of Natural Selection

In nature, there is a tendency toward overpopulation, but not all offspring survive. Variations exist and are inherited; advantageous variations lead to longer life and more offspring.