Vets 1060 Lecture 7 & Lecture 8

Introduction

  • Speaker welcomes everyone and discusses recent events affecting attendance.
  • Reminder of upcoming practical sessions in Vets 10 60.

Important Notes for Practicals

  • Requirements for Prac Attendance:
    • Closed shoes (no sandals).
    • A lab coat must be worn, fastened at the front or back.
    • No food or drink in laboratories.
    • Long hair should be tied back.
  • Lab Safety:
    • Lab coats should not be worn outside the lab.
  • Prac Notes:
    • Will be posted online for reference.

Examination Information

  • Upcoming INSIM (Integrated Science Exam).
  • Review of concepts covered: classification, evolution, molecular basis of evolution.
  • Importance of previous lectures leading to this exam.

Molecular Biology Overview

  • DNA Structure: In animals, DNA is organized into chromosomes. Eukaryotes have multiple chromosomes housed in a nucleus.
  • Definitions:
    • Genes: Blueprints for life, coding for proteins crucial for cellular functions.
    • Phenotype: Observable characteristics influenced by genes.

Genetic Relationships and Evolution

  • Key Concepts:
    • Orthologous Genes: Genes in different species derived from a common ancestor.
    • Paralogous Genes: Genes produced by duplication within a species.
    • Common descent explained by Darwin, highlighting how species evolve from common ancestors.

Mutation and Variation

  • Significance of Mutations:
    • Mutations occur due to various factors, leading to genetic diversity.
    • Can be endogenous (spontaneous) or exogenous (external influences like radiation).
    • Mutations can lead to genetic disorders but can also be beneficial.
  • Natural Selection:
    • Process by which favorable traits gain prevalence across generations.
    • Examples include Darwin's finches (varying beak shapes) and the peppered moth.

Detailed Examples of Evolution

  • Case studies:
    • Trypanosomes: Examples of how parasites evade immune responses through genetic variation.
    • Pig Breeding: Historical examples of how mutations in coloration have been selectively bred.

Mechanisms of Diversity in Populations

  • Drivers of Change:
    • Mutation, Gene Flow (movement between populations), Genetic Drift (random events affecting population diversity), and Natural Selection.
    • The interplay of these factors can lead to population bottlenecks and founder effects.
  • Example: Northern Elephant Seal, reduced genetic diversity due to historical population decline.

Molecular Phylogenetics

  • Phylogenetic Trees: Modern understanding of organism relationships based on shared genetic material.
  • Constructing Phylogenies: Use of gene sequences to explore evolutionary relationships.

Eukaryote Origins and Diversity

  • Serial Endosymbiosis Hypothesis:
    • Describes how prokaryotic cells led to the formation of eukaryotes by incorporating smaller prokaryotes (e.g., mitochondria from aerobic bacteria).
  • Myxotricha paradoxa:
    • Example of a complex organism that exemplifies endosymbiotic relationships, housing multiple genomic components within a single cell.

Eukaryotic Diversity

  • Discussion of diverse eukaryotic forms, including single-celled and multicellular organisms.
  • Importance of understanding single-celled eukaryotes in relation to multi-cellular forms like plants and animals.
  • Important Groups:
    • Excavata: Flagellated organisms (example: Giardia).
    • Fungi: Closely related to animals, distinct from plants.

Conclusion

  • The interconnectedness of all forms of life through shared ancestry and evolutionary processes.
  • Reminder for students to engage with the material for exams, with a focus on understanding concepts presented throughout the course.
  • Speaker plans to discuss further eukaryotic diversity in upcoming lectures.