1. The theory of natural selection states that: A. individuals that live the lon

Question

1. The theory of natural selection states that:

A. individuals that live the longest are best adapted and selected for survival in the next generation

B. individuals that mutate in response to their environment will survive at the expense of those individuals who are genetically stable

C. only the largest and strongest survive

D. the best-adapted individuals survive and reproduce, contributing the most genes to the next generation.

2. Pharyngeal slits are present in the embryos of organisms as diverse as fish, chickens, and humans. Why would organisms as different as these have similar embryonic structures?

A) The organisms shared a common ancestor whose embryos had pharyngeal slits.

B) The pharyngeal slits is an acquired characteristic that just happens to look similar in different species.

C) The organisms shared a common ancestor, which did not have the slits, but natural selection created similar changes in the embryos over time.

D) The pharyngeal slits develop into gills because all species need to survive in a water environment at some point in their life cycle

3. Paleontoligists have discovered many trasitional forms that link past on present in the fossil record.

A) True

B) False

Explanation / Answer

1) D. the best-adapted individuals survive and reproduce, contributing the most genes to the next generation.

Natural selection basically states that some individuals in a population are better adapted to their environment, and, as a result, will survive. Because of this, their genes get passed on and the next generation may also be well adapted to the current environment.

The largest and strongest may not be the best adapted in their environment and  they don't mutate in response to their environment. mutations occur randomly. those that benefit the individual survive, while those that are deleterious do not. Some mutations may not effect survival at all individuals.

2) A) The organisms shared a common ancestor whose embryos had pharyngeal slits.

Pharyngeal slits similar to gill slits are briefly present during the embryonic stages of tetrapods development. The presence of gill-like slits in the neck of the developing human embryo. The vertebrate pharyngeal pouches and not the neck slits are homologous to the pharyngeal slits of invertebrate chordates. Gill slits are present at some stage of life in all chordates. The presence of pharyngeal slits in hemichordates led to debates of this structure was homologous to the slits found in chordates or a result of convergent evolution.

3) A) True. Yes, Paleontoligists have discovered many trasitional forms that link past on present in the fossil record. Transition form of paleontology as a  transitional fossil is fossilized remains of a life form that exhibits traits common to both an ancestral group and derivative descendant group. The descendant group is differentiated by gross anatomy and mode of living from the ancestral group. Transitional fossils are direct ancestors of more recent groups, though they are regularly used as models for such ancestors. Transitional creatures should resemble intermediate species, having skeletal and other body features in common with two distinct groups of animals, such as fish and amphibians or reptiles and mammals.

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.