BIO153 Lecture 1 notes

Introduction to Biodiversity

  • Biodiversity: Refers to the variety of life on Earth, including all organisms, their genetic differences, and ecosystems.
  • Last Universal Common Ancestor (LUCA):
    • Hypothetical organism existing about 4 billion years ago.
    • Represents the last common ancestor of all cellular life today.
    • This divergence occurred through natural selection, resulting in the tremendous diversity of life forms observed today.
  • Evolution occurs over billions of years, and while fossils provide some insight, direct samples from the past are rare.

Domains of Life

  • Three primary domains:
    1. Domain Bacteria:
    • Most diverse and widespread prokaryotes.
    • Classified into multiple kingdoms; characterized by rod-shaped structures (bacterial cells).
    1. Domain Archaea:
    • Prokaryotes often found in extreme environments (e.g., saline lakes, hot springs).
    • Also classified into multiple kingdoms with round-shaped structures (archaeal cells).
    1. Domain Eukarya:
    • Contains multicellular organisms that include kingdoms like Animalia, Plantae, Fungi, and Protists.
  • Polytomy: A branch point in evolutionary relationships indicating unresolved divergence patterns.

Organism Adaptation and Classification

  • Organisms adapt to their habitats through evolutionary processes, but there is no single answer for how these variations occur.
  • Taxonomy: The science of naming organisms.
  • Phylogeny: Study of evolutionary relationships among organisms.
    • Example:
      • Taxa of humans:
      • Domain: Eukaryota
      • Kingdom: Animalia
      • Phylum: Chordata
      • Class: Mammalia
      • Order: Primates
      • Family: Hominidae
      • Genus: Homo
      • Species: Homo sapiens

Biodiversity in Everyday Life

  • Observation of biodiversity:
    • Various flowering plants can be found in natural habitats and human-planted settings.
  • Importance of biodiversity to humans:
    • Understanding biodiversity educates us about our environment and ourselves.

Conservation Ecology

  • Organisms interact constantly with their environments and each other.
    • Example:
    • Predator-prey dynamics:
      • Populations of predators and prey, such as the Canada lynx (predator) and snowshoe hare (prey), synchronize through ecological interactions.
  • Environmental changes, like logging and road building, disrupt ecosystems (e.g., affecting the woodland caribou in Canada).

Human Health and Disease

  • Parasites and host interactions:
    • Many organisms can infect humans, necessitating understanding for effective treatment.
    • Notable pathogens:
    • Mycobacterium tuberculosis (causes tuberculosis)
    • Monkeypox virus (causative agent: mpox)
    • Human Immunodeficiency Virus (HIV; causes AIDS)
  • Epidemics vs. Pandemics:
    • Epidemic: Significant rise in disease occurrence above normal in a local population.
    • Pandemic: Global epidemic affecting multiple continents.
  • COVID-19:
    • Caused by the SARS-CoV-2 virus, resulting in significant global health and social impacts.
    • Initial cases reported in December 2019, leading to a pandemic declaration by WHO in March 2020.
  • Historical context:
    • SARS-CoV-2 is not the first coronavirus to affect humans; prior coronaviruses include SARS-CoV-1 and MERS-CoV.
  • Statistics:
    • As of September 2022:
    • Over 612 million cases globally and approximately 6.5 million deaths.
    • Vaccination efforts began in early 2021 in Ontario.

Course Information

  • BIO153 Week 1 To-do:
    • Review syllabus and course materials on Quercus.
    • Attend lectures and tutorials with an overview of course structure.
    • Labs commence in week 2, with available materials posted online in advance.