ch 18 bio

Introduction

• The review session will cover chapters 13, 15, and 18, with chapter 13 being particularly challenging.

• Emphasis on Darwin's "The Origin of Species" - a significant book in biology that goes beyond his journey in the Beagle.

Darwin and Natural Selection

• Evolution concepts introduced by Darwin, including natural selection and environmental impact on species.

• Prior to Darwin, beliefs about nature were based on spiritual thoughts rather than experimentation.

• Evolution is viewed as a unifying concept in biology, supported by extensive evidence.

• Similarities among living organisms hint at a common ancestor, while differences reflect evolutionary processes.

Taxonomy and Classification

• Taxonomy matured in the mid-eighteenth century, focusing on classifying organisms based on traits.

• Linnaeus introduced binomial nomenclature, providing a scientific naming system based in Latin (genus and species).

• Each species has an ideal structure and function, leading to the classification into domains based on cellular structure.

Impact of Environment on Evolution

• Factors such as migration, geographic isolation, and struggle for existence play roles in natural selection.

• Geographic isolation can lead to distinct adaptations (e.g., species living on islands vs. mainland).

• Local environments can create microclimates affecting species' adaptations.

Comparative Anatomy and Evolution

• Curvier's comparative anatomy laid the groundwork for classifying animals based on structural similarities.

• Lamarck's ideas about the inheritance of acquired traits (e.g., giraffes' necks) were significant in early evolution thoughts.

Observational Studies in Evolution

• Darwin's finch observations demonstrate natural selection based on beak adaptations to food sources.

• Changes in species due to hunting pressures (e.g., marine snail shells) illustrate evolutionary responses.

• Bacterial resistance to antibiotics is a current example of evolution in action caused by over-prescription.

Evidence of Evolution

• Fossil records document the succession of life forms and can indicate evolutionary changes.

• Anatomical evidence shows homologous structures across species, suggesting common ancestry.

• Embryological studies reveal similarities in vertebrae embryos, indicting shared descent.

Biochemical Evidence

• DNA sequencing technology allows comparison of genetic material, providing evidence for evolutionary relationships.

• All organisms share biochemical molecules (proteins, nucleic acids, etc.), indicating common ancestry.

• Variations at the amino acid level in proteins (like cytochrome c) can reveal insights into evolutionary paths.

Artificial Selection

• Artificial selection demonstrates human influence on evolution through breeding practices (e.g., pet breeds).

• Genetic modification in agriculture raises concerns about food safety and environmental impacts.

• Personal anecdotes highlight the complexities of genetic modification in food production and consumption.

Conclusion

• The discussion emphasizes the importance of both natural and artificial selection in shaping life forms.

• Continuous environmental changes require ongoing adaptations in species.