Ch. 10 - Principles of Evolution

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Questions and Answers

What are the four main principles of natural selection?

Variation, overproduction, adaptation, descent with modification.

What does the phrase 'Natural selection can act only on existing traits' mean?

It means natural selection can only act on traits that are already present and that structures may take on new functions over time.

Give an example of evolution evidence from fossils.

Fossils in older layers are more primitive than those in newer layers.

Give an example of evolution evidence from geography.

Populations can show variation from one island to another, with island species most closely resembling nearest mainland species. Signup and view all the answers

Give an example of evolution evidence from embryology.

Identical larvae but different adult body forms. Signup and view all the answers

How are genes and proteins similar to homologous structures in evolution?

Genes determine the structure and function of proteins, and homologous structures reveal evolutionary relationships. Signup and view all the answers

What does the similarity in forelimb structures of humans, bats, and moles indicate?

They share a common ancestor. Signup and view all the answers

What does the different neck lengths of tortoises illustrate?

Variation between species. Signup and view all the answers

Why did an insect species evolve resistance to a pesticide?

Because spraying pesticides selected for insects that were able to survive and reproduce. Signup and view all the answers

Why were some weeds able to survive a herbicide that killed 99% of the population?

Genetic variation in the population allowed some weeds to survive. Signup and view all the answers

In a population, natural selection acts on what?

Heritable differences. Signup and view all the answers

What explains the presence of light-colored lizards in the White Sand region of New Mexico?

Light-colored lizards are more likely to survive and reproduce in the White Sand regions. Signup and view all the answers

What is catastrophism?

The theory that states that natural disasters shaped Earth's landforms and caused extinction of some species. Signup and view all the answers

What is gradualism?

The principle that states changes in landforms result from slow changes over a long period of time. Signup and view all the answers

Define population in an ecological context.

All the individuals of a species that live in the same area. Signup and view all the answers

What is variation?

Differences in physical traits of an individual from the group to which it belongs. Signup and view all the answers

What is an adaptation?

An inherited trait that is selected for over time because it allows organisms to better survive in their environment. Signup and view all the answers

What is evolution?

Change in the species over time; the process of biological change by which descendants come to differ from their ancestors. Signup and view all the answers

What are vestigial structures?

Remnants of an organ or structure that functioned in earlier ancestors. Signup and view all the answers

What are analogous structures?

Body parts that are similar in function but differ structurally. Signup and view all the answers

What is a fossil?

Trace of an organism from the past. Signup and view all the answers

What is paleontology?

The study of fossils or extinct organisms. Signup and view all the answers

Study Notes

Principles of Evolution

Natural Selection: Occurs through four principles: variation, overproduction, adaptation, and descent with modification.
Variation: Genetic variations are crucial for driving evolutionary changes; without them, no adaptation occurs.
Overproduction: Species produce more offspring than the environment can support, increasing survival chances for some.
Adaptation: Organisms with traits suited for their environment have higher reproductive success, allowing them to pass on advantageous traits.
Descent with Modification: Offspring inherit modified genes from parents, leading to evolution over generations.

Existing Traits in Natural Selection

Natural selection utilizes existing traits; cannot create new traits. Traits may evolve new functions over time.

Evidence of Evolution

Fossils: Older fossil layers contain more primitive forms than newer layers, indicating progression over time.
Geography: Island populations often show variations that resemble the nearest mainland species, suggesting evolutionary adaptation.
Embryology: Similar embryonic stages reveal common ancestry despite differing adult forms across species.
Anatomy: Homologous structures share a common evolutionary origin, despite performing different functions in various species.

Genes, Proteins, and Homologous Structures

Genes dictate protein structure and function, which reflect evolutionary relationships indicated by anatomical and ecological differences.

Common Ancestry

Similar forelimb structures in humans, bats, and moles signify a shared common ancestor, demonstrating evolutionary ties.

Variation in Species

Differences like neck length among tortoises illustrate variation within species, fundamental for natural selection.

Resistance to Pesticides

Insect populations that evolve resistance to pesticides do so because those with survival traits reproduce more successfully after pesticide application.

Surviving Weeds

Genetic variation among weeds explains why some survive herbicide application despite 99% being killed, showcasing natural selection.

Natural Selection Focus

Natural selection targets heritable traits within populations, driving evolution through advantageous adaptations.

Light-Colored Lizards Example

Light-colored lizards thrive in the White Sand region due to their superior camouflage, enhancing their survival and reproductive success.

Catastrophism vs. Gradualism

Catastrophism: Natural disasters have historically shaped Earth's landscape and led to extinctions.
Gradualism: Landform changes result from gradual processes occurring over extensive time periods.

Definitions

Population: Collective individuals of a species within a specific location.
Variation: Physical differences among individuals within a group.
Adaptation: Traits that improve an organism's survival and reproduction in its environment.
Evolution: The long-term biological changes through which species diverge from ancestors.
Vestigial Structures: Remnants of organs or structures that were functional in ancestral forms but have lost their original use.
Analogous Structures: Body parts with similar functions across different organisms but differing structures.
Fossil: The preserved trace of an ancient organism, providing evidence of evolutionary history.
Paleontology: The field focused on the study of fossils and ancient life forms.

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Description

This quiz focuses on the four main principles of natural selection: variation, overproduction, adaptation, and descent with modification. You'll explore how each principle contributes to the process of evolution. Test your understanding with flashcards designed to enhance your knowledge of evolutionary biology.