Chapter 15.1, Problem 3MI

Summary Introduction

To define:

The given words using a book or a dictionary.

Introduction: Darwin read an essay by Thomas Malthus that suggested that if the human population is unchecked it would soon outgrow its food supply leading to a competitive struggle for existence. Darwin got the idea that this principle could also be applied to natural world. He gave a new theory about the origin of species.

Answer to Problem 3MI

Artificial selection- Breeding organisms with specific traits in order to produce offspring with identical traits is called artificial selection.

Natural selection- The mechanism of breeding that occurs in nature when organisms with favorable variations survive, reproduce and pass their variations to the next generation, is called natural selection.

Evolution- The changes that occur in populations over time is called evolution.

Explanation of Solution

Darwin hypothesized that new species could appear gradually through changes in ancestral species but he could not understand how such a process could work. He consulted animal breeders- pigeon breeders in particular and found that a breeder can promote certain traits by selecting and breeding animals that have most prominent expression of traits. Such a method of selective breeding is called artificial selection. The modern theory of evolution is the principle concept in biology. Charles Darwin gave a theory of natural selection. He argued that if enough time is given, natural selection could modify a population to produce new species. This occurs when individual in a population show differences called variations which can be inherited. Variations that increase reproductive success will have a greater chance of being passed on than those that do not increase reproductive success. Later Darwin compiled evidence for evolution and explained natural selection as a mechanism for the origin of species.

When changes accumulate in a group of organisms over a period of time, it is called evolution. It is a key concept that helps in understanding biology. It explains the diversity of organisms and predicts changes.