Ch. 10 - Principles of Evolution

Natural selection is based on four main principles: variation, overproduction, adaptation and descent with modification. Briefly explain how each of these principles is necessary for natural selection to occur.

Variation = natural variation in genetic code, due to mutations. Without this, change would never occur. overproduction = producing more offspring than will survive to maturity. Reduces the chance of being wiped out. adaptation = ability to withstand changes in the environment. Those more able to withstand said change will be more prolific reproducers. descent with modification = the mutation of genes into other forms as a result of natural variation, occurring when the offspring's genetic information is first generated, rather than over a lifetime of mutation.

The different neck lengths of the tortoises shown above is an example of

Variation between species

population

All the individuals of a species that live in the same areas

Analogous structures.

Body part that is similar to function as a body part of another organism but is structurally different

evolution

Change in the species over time process of biological change by which descendants come to differ from their ancestors.

Variation

Differences in physical traits of an individual from the group to which it belongs

Evidence of evolution comes from diverse sources, such as fossils, geography, embryology, and anatomy. Briefly describe one example of evidence for evolution from each of these sources.

Fossils: Fossils in older layers are more primitive than those in newer layers Geography: Population can show variation from one island to another, Island species most closely resemble nearest mainland species Embryology: Identical larvae but different adult body form, Similar embryos and diverse organisms

A herbicide killed 99% of a weed population. Which of the following is the best biological explanation for some weeds being able to survive?

Genetic variation in the population allowed some weeds to survive

In a population, natural selection acts on

Heritable differences

adaption

Inherited trait that is selected for over time because it allows organisms to better survive in their environment

Explain what is meant by the sentence " Natural selection can act only on existing traits"

It can only act on already existing traits and structures take new functions along with original function

Which of the following is the best explanation for the presence of the light-colored lizards in the White Sand region of New Mexico, when darker lizards live in the surrounding areas?

Light-colored lizards are more likely to survive and reproduce in the White Sand regions

Gradualism

Principle that states that the changes in landforms result from slow changes over a long period of time

Vestigial structures.

Remnants of an organ or structure that functioned and an earlier

After many generations, an insect species evolved resistance to a particular pesticide. This occurred because spaying pesticides

Selected for insects that were able to survive and reproduce

The similarity in forelimb structures of humans, bats, and moles is evidence that they

Share a common ancestor

paleontology

Study of fossils or extinct organisms

How are genes and proteins similar to homologous structures when determining evolutionary relationships among species?

The genes determine the structure and function of the proteins as the homologous structures differ from environment to environment

Catastrophism

Theory that states that natural disasters such as floods and volcanic eruptions shaped Earth's land forms and caused extinction of some species

fossil

Trace of an organism from the past.