lecture recording on 11 March 2025 at 11.06.32 AM

Overview of Evolution and Genetics

• Shift from biblical explanations to scientific understanding of evolution.

• Chapter 18 serves as a bridge: connects genetics and molecular genetics to evolution.

Importance of Bioinformatics

• Bioinformatics: combines biology with statistics and computing.

• Skills in this area essential for making predictions about treatments and diagnoses.

• Genomic diversity: size, number of genes, gene density influence evolutionary studies.

• Key point: just because a genomic region lacks known function doesn't mean it's useless; it may have undiscovered roles.

Transposable Elements

• Transposons: segments of DNA that can move around within the genome.

• Discovery by Barbara McClintock: identified gene mobility in corn genetics.

• Initial skepticism due to the novelty of her findings; recognized later for their importance.

• Mechanisms of transposable elements:

  • Make copies of themselves and insert elsewhere (copy and paste).

  • Cut and reintegrate into different chromosome locations (cut and paste).

• Thought to explain non-coding DNA with unknown function.

• Consideration of how these elements might aid in evolutionary processes.

SNPs and Evolution

• SNPs (Single Nucleotide Polymorphisms): variations within the 1% of the genome used in forensic analysis.

• Evolution demonstrates similarity in genes across species, as shown in homeobox (Hox) genes widely found in insects, indicating similar developmental mechanisms.

• Concepts of gradualism in evolution emphasized through fossil discoveries.

Historical Context of Evolutionary Theory

• Darwin vs. predecessors:

  • Darwin contemporary with Mendel but they had different circles of influence.

  • Earlier views saw major changes attributed to catastrophic events (e.g., Cuvier).

  • Gradual change concept by Hutton and Lyell laid groundwork for Darwin's theories.

• Thomas Malthus' ideas on population growth and resources influenced Darwin’s views on natural selection.

Lamarck's Contributions and Missteps

• Lamarck's idea: species adapt to their environments over time.

• Introduced the inheritance of acquired characteristics, which was later disproven (e.g., rat tail experiment).

• His insights on environmental influence on evolution were acknowledged, even though he had flawed theories.

Charles Darwin's Journey

• Darwin's background: initially aimed to study medicine, then theology, ultimately becoming a naturalist.

• Voyaged on the HMS Beagle, where extensive observations were made, especially in the Galapagos Islands.

• Observed unique adaptations in fauna, such as tortoises and finches that varied by island.

Origin of Species

• After years of research, Darwin published On the Origin of Species, outlining natural selection.

• Highlights of Darwin's ideas: species evolve over time due to natural selection and adaptation.

• Alfred Russel Wallace independently arrived at similar conclusions, prompting collaboration and co-publication with Darwin.

• Highlights importance of thorough evidence in establishing scientific theories.

Implications of Darwin's Work

• Evolutionary theory fundamentally changed biological sciences, providing a framework for understanding life's diversity.

• The theory remains a cornerstone of biology, influencing ecological studies and genetics.