Evolution: Gradualism and Punctuated Equilibrium

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Questions and Answers

Who wrote the book on the theory of Natural Selection?

Charles Darwin

What is the best scientific explanation for both the unity and diversity of life?

Cell Theory

Quantum Theory

Theory of Evolution (correct)

Theory of Relativity

What are groups of interbreeding organisms in the same area called?

Population

What happens in a large population concerning evolutionary rate?

Lower evolutionary rate, more likely to appear on the fossil record. Signup and view all the answers

What happens in a small population concerning evolutionary rate?

Easier for evolution, higher evolutionary rate. Signup and view all the answers

What is evolution?

Change in variation over time; process by which modern organisms have descended from ancient organisms. Signup and view all the answers

What is natural selection?

Nature's way of selecting the best adaptations for a particular environment. Signup and view all the answers

What are the four types of polygenic selection?

Stabilizing, Directional, Disruptive, Sexual Selection. Signup and view all the answers

What is an adaptation?

Inherited characteristic that increases an organism's chance of survival. Signup and view all the answers

What is reproductive isolation?

The inability of a species to breed successfully with related species due to barriers. Signup and view all the answers

What are the two main ways to describe the rate of evolutionary change?

Gradualism and Punctuated Equilibrium. Signup and view all the answers

What is gradualism?

Change that is incremental and slow that happens over time. Signup and view all the answers

Approximately how long does it take for gradualism to occur?

Millions of years. Signup and view all the answers

What is punctuated equilibrium?

Pattern of evolution characterized by long stable periods interrupted by brief periods of rapid change. Signup and view all the answers

When does punctuated equilibrium occur?

Rapid change occurs when a smaller population of species is isolated from the parent population. Signup and view all the answers

Approximately how long does it take for punctuated equilibrium to occur?

Hundreds of thousands of years. Signup and view all the answers

Who proposed the term 'punctuated equilibrium'?

Niles Eldredge and Stephen Jay Gould. Signup and view all the answers

What is a vestigial structure?

A structure that an organism has that is no longer useful. Signup and view all the answers

What are homologous structures?

Structures that have different mature forms in different organisms but develop from the same embryonic tissues. Signup and view all the answers

What are analogous structures?

A trait or an organ that appears similar in two unrelated organisms. Signup and view all the answers

What is common ancestry?

A group of organisms share common descent if they have a common ancestor. Signup and view all the answers

What is divergent evolution?

Process by which a single species evolves into several different forms. Signup and view all the answers

What is speciation?

Formation of new species. Signup and view all the answers

What is the struggle for existence?

Competition to survive, not all of a species will survive. Signup and view all the answers

What is overproduction in terms of evolution?

More will be born than can survive. Signup and view all the answers

What is artificial selection?

When humans decide which characteristics will survive in a population. Signup and view all the answers

What are acquired traits?

Characteristics that an organism gets during their lifetime that are not genetic. Signup and view all the answers

What is diversity in biology?

All of the different species on Earth. Signup and view all the answers

What is variation?

The differences within a single species. Signup and view all the answers

What is a species?

Group of similar organisms capable of interbreeding and producing fertile offspring. Signup and view all the answers

Study Notes

Evolution Basics

Charles Darwin authored the book on Natural Selection, foundational to the theory of evolution.
The Theory of Evolution explains both the unity and diversity of life as proposed by Darwin.

Populations and Evolutionary Rates

Populations consist of interbreeding organisms in a specific area.
Large populations exhibit lower evolutionary rates and are more commonly found in fossil records.
Small populations have higher evolutionary rates, making evolution easier and more rapid.

Key Concepts in Evolution

Evolution involves a change in variation over time, leading to modern organisms descending from ancient ones.
Natural selection, known as "survival of the fittest," drives evolution by favoring traits adapted to specific environments.

Types of Natural Selection

Stabilizing Selection eliminates extremes, favoring average phenotypes.
Directional Selection favors one extreme phenotype over another.
Disruptive Selection promotes both extreme phenotypes.
Sexual Selection influences traits based on male attraction, contributing to sexual dimorphism.

Adaptation and Isolation

Adaptations are inherited traits enhancing survival chances.
Reproductive isolation prevents species from breeding successfully due to various barriers, including geographical and genetic.

Evolutionary Change Rates

Gradualism describes slow, incremental evolutionary change over millions of years.
Punctuated Equilibrium proposes long stable periods interrupted by brief, rapid changes, often occurring in smaller isolated populations over hundreds of thousands of years.

Historical Contributors

Niles Eldredge and Stephen Jay Gould introduced the term "punctuated equilibrium."

Structural Evidence of Evolution

Vestigial structures are remnants of features once useful to a common ancestor.
Homologous structures showcase different mature forms in organisms that arise from the same embryonic tissues, indicating common ancestry.
Analogous structures appear similar in unrelated organisms but do not share a common lineage.

Evolutionary Processes

Common ancestry means a group shares descent from a common ancestor.
Divergent evolution, or adaptive radiation, occurs when a small group evolves into diverse forms adapted to different environments.
Speciation is the formation of new species driven by evolutionary changes.

Mechanisms of Evolution

The struggle for existence highlights the competition among individuals within a species.
Overproduction leads to more offspring being born than can survive.
Artificial selection, or selective breeding, involves human choices over which traits persist in a population.

Diversity and Variation

Diversity encompasses all species on Earth, while variation refers to differences within a single species.
A species is defined as a group of similar organisms capable of interbreeding and producing fertile offspring.

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Description

Test your knowledge on key concepts of evolution, including Charles Darwin's contributions and the definitions of critical terms such as 'Theory of Evolution' and 'Population'. This quiz will help you understand the foundational ideas behind the gradual and punctuated changes in species over time.