Biodiversity and Biological Classification

Biodiversity

• Estimates: Around 8-10 million different species of organisms on Earth, but only 20% are known to science
• Biodiversity Definition: The variety within and among living species

Biological Classification

• Systematists: Scientists who categorize organisms
  • Collections include animal specimens in natural history museums, plant specimens in herbaria, and microbes in type-collection centers

Geological Eras and Major Life Features

• Life History: Divided into four major eras - with subdivisions in all but the first
  • Precambrian Era: Formation of Earth (4.5 billion years ago), early single-celled organisms
  • Paleozoic Era (543 - 251 million years ago)
  • Cambrian (495 mya): Modern animal groups appear
  • Permian (290 - 251 mya): 95% extinction at end
  • Mesozoic Era (251 - 65 mya): Age of dinosaurs
  • Triassic and Jurassic periods feature large reptiles
  • Cenozoic Era (65 mya - present)
  • Mammals and flowering plants diversify

Biological Classification Hierarchy

• Levels:
  • Domain (Eukarya)
  • Kingdom (Animalia)
  • Phylum (Chordata)
  • Class (Mammalia)
  • Order (Primates)
  • Family (Hominidae)
  • Genus (Homo)
  • Species (Homo sapiens)

Domains of Life

• Three Domains: Bacteria, Archaea, Eukarya
  • Prokaryotes: Bacteria and Archaea
  • Eukaryotes: Include Protists, Plants, Animals, Fungi

Evolutionary Relationships

• DNA Comparisons: Used to establish evolutionary relationships
  • Closely related species share more DNA similarity

Microbial Importance

• Microbes: Small organisms, significant for oxygen production
  • Decomposers: Bacteria and fungi break down organic matter
  • Biomass: Microbial mass surpasses larger life-forms

Plant Evolution and Features

• History: Plants evolved on land ~400 million years ago
  • Transition from non-vascular to vascular plants enables large growth
  • Development of seeds and flowers

Virus Characteristics

• Viruses: Non-living entities, require a host for reproduction
  • Cause various human diseases (e.g., Polio, HIV)
  • Not capable of homeostasis or growth independently

Animal Diversity (Kingdom Animalia)

• Major phyla categorized by organization and features:
  • Porifera: Sponges
  • Cnidaria: Jellyfish, corals
  • Mollusca: Snails, octopuses
  • Arthropoda: Insects, arachnids
  • Chordata: Vertebrates

Plant Diversity and Development

• Kingdom Plantae: Eukaryotic, multicellular, mostly autotrophic
  • Features evolution of vascular tissues, seeds, flowers

Fungal Diversity

• Kingdom Fungi: Major phyla based on spore production
  • Includes Zygomycota (bread mold), Ascomycota (yeasts)
  • Mycorrhizae: Fungal symbiotic relationships with plant roots

Evolutionary Classification Challenges

• Phylogeny: Study of evolutionary relationships among species
  • Complications include loss of traits or convergent evolution
  • Fossil and DNA evidence guide taxonomy

Conclusion

• Biodiversity depicts complex evolutionary histories, organism interactions, and ecological significance of life choices. Understanding biological classification helps in mapping these relationships succinctly and accurately, revealing nature's intricacies.