Chapter 2, Problem 1Q

Review the kinds of evidence for evolution analyzed in Sections 2.1–2.5. List the sources of evidence that were available to Darwin and those that appeared later. For example, of the evidence for microevolution discussed in Section 2.1, Darwin knew, and wrote, about divergent strains of domestic plants and animals and about vestigial structures. However, in Darwin’s day no one had ever directly observed change across generations in natural populations. For each section, indicate which evidence you consider strongest and which you consider weakest. Explain why.

Summary Introduction

To review: The kinds of evidence for evolution analyzed.

Introduction: Science is the method of “acquiring knowledge” based on facts learned through experiments and observations. The applications and research studies on science help to improve the standard of lives.

Explanation of Solution

The kinds of evidence for evolution that are analyzed are grouped into 5 categories and are given as follows:

• Evidence of speciation
• Evidence of microevolution
• Evidence from common ancestors
• Evidence from macroevolution
• The age of the Earth.

Summary Introduction

To list: The sources of evidence that were available to Darwin and those that appeared later.

Explanation of Solution

Evidence of microevolution: It is the study on the way in which the populations change over generations. Selective breeding is one of the situation in which microevolution can take place. Selective breeding is otherwise referred to as artificial selection and occurs when the humans selectively breed useful traits in organisms such as crops and livestock. Darwin knew about different strains of domestic plants and animals and included this in his work.

Evidence of speciation: It is a process of creating a new species from an older one. Both experiments in the laboratory and natural populations are examples of speciation. Evidence from natural populations, such as Darwin’s finches, is available for evidence.

Evidence from common ancestors: Similarity or homology between two organisms also gives the evidence for evolution. Anatomical homologies were known to Darwin but molecular homologies were not.

Evidence from macroevolution: It is the study of macroevolution changes in the fossil record. Fossils are any traces of organisms that lived in the past. The first type of fossil evidence is extinction and succession. Georges Cuvier found species that were only found in the fossil record. Others believed that they were the members of the current species.

The age of the Earth: Hutton suggests that the processes that are responsible for the formation of Earth are still happening today. Based on this, they started to make a geological time scale based on this type.

Summary Introduction

To explain: The evidence that is considered as the strongest and weakest and the reason corresponding to the decision.

Explanation of Solution

Microevolution is strong evidence for evolution; for example, vestigial structures in the hind limbs of wolves and whales. Wolves and whales are considered to share a common ancestor as whales have hind legs similar to wolves and other walking mammals.

In natural populations, speciation is strong evidence for evolution. Darwin’s finches are strong evidence for speciation that supports evolution.

Common ancestors provide strong evidence for evolution. Both chimps and bonobos shared repeats with humans, but less relative primates such as orangutans and gorillas do not.

Macroevolution provides strong evidence for evolution. Few transitional fossils were identified by Darwin, but a large number of fossils have been discovered today, which provide strong evidence for evolution.

The evidence of age of the Earth is considered as the weakest. The extreme age of the Earth is very important as the process of evolution is comparatively very slow. Without an old Earth, Darwin’s model of evolution would not be possible. Darwin did not know the age of Earth for his theory of evolution and was concerned about a possible young Sun, making the Earth even younger.