BIO101 – Topic 32: Evolution and Natural Selection
Course Code: BIO 101
Course Name: General Biology
© Lesuyai Organic Guides 2025
(Original | Educational | Professional | Plagiarism-Free | A4 Format | With Review Questions &
Answers)
1. Introduction
Evolution is the process through which living organisms undergo gradual changes over long periods
of time, resulting in the diversity of life observed today. It explains how species originate, adapt, and
become extinct.
2. Concept of Evolution
Definition: Evolution refers to the gradual change in inherited characteristics of populations over
generations.
Historical Background: Ancient philosophers like Aristotle discussed changing life forms. Lamarck
suggested inheritance of acquired traits, but Darwin and Wallace later proposed natural selection.
Key Contributors:
• Charles Darwin – proposed evolution by natural selection.
• Alfred Russel Wallace – co-developer of the theory.
• Gregor Mendel – discovered heredity principles.
3. Evidence for Evolution
• Fossil Record: Shows gradual change of species.
• Comparative Anatomy: Homologous and analogous structures.
• Embryology: Early similarities suggest common ancestry.
• Molecular Evidence: DNA and protein similarities.
• Biogeography: Distribution of species supports evolution.
Course Code: BIO 101
Course Name: General Biology
© Lesuyai Organic Guides 2025
(Original | Educational | Professional | Plagiarism-Free | A4 Format | With Review Questions &
Answers)
1. Introduction
Evolution is the process through which living organisms undergo gradual changes over long periods
of time, resulting in the diversity of life observed today. It explains how species originate, adapt, and
become extinct.
2. Concept of Evolution
Definition: Evolution refers to the gradual change in inherited characteristics of populations over
generations.
Historical Background: Ancient philosophers like Aristotle discussed changing life forms. Lamarck
suggested inheritance of acquired traits, but Darwin and Wallace later proposed natural selection.
Key Contributors:
• Charles Darwin – proposed evolution by natural selection.
• Alfred Russel Wallace – co-developer of the theory.
• Gregor Mendel – discovered heredity principles.
3. Evidence for Evolution
• Fossil Record: Shows gradual change of species.
• Comparative Anatomy: Homologous and analogous structures.
• Embryology: Early similarities suggest common ancestry.
• Molecular Evidence: DNA and protein similarities.
• Biogeography: Distribution of species supports evolution.
