Understanding Diversity and Evolution

Diversity Overview

• Diversity encompasses the variety of life forms on Earth, including species, genetic differences, and ecosystems.
• It accounts for different organisms, their habitats, and ecological roles.

Common Ancestor

• Species sharing similar evolutionary histories indicate a recent common ancestor.
• Understanding evolutionary relationships hinges on this concept, often depicted in phylogenetic trees.

Three Domains of Life

• Bacteria:
  • Prokaryotic and unicellular, lacking nucleus and organelles.
  • Essential for nutrient cycling and decomposition; some species are pathogenic.
• Archaea:
  • Prokaryotic, unicellular, genetically distinct from bacteria.
  • Often extremophiles, thriving in harsh environments, contributing to biogeochemical cycles.
• Eukarya:
  • Comprised of eukaryotic organisms with nuclei and organelles.
  • Includes diverse life forms categorized into four kingdoms:
    • Plantae: Autotrophic, multicellular organisms performing photosynthesis (e.g., trees).
    • Animalia: Heterotrophic, multicellular organisms that consume organic material (e.g., mammals).
    • Fungi: Mostly multicellular, heterotrophic organisms absorbing nutrients (e.g., mushrooms).
    • Protista: Diverse group, primarily unicellular, with both autotrophic and heterotrophic members.

Species Definition and Concepts

• A species is defined as a group of organisms capable of interbreeding and producing fertile offspring.
• Approximately 2 million species are identified, with estimates suggesting up to 20 million may exist.
• Species Concepts:
  • Morphological: Based on physical traits.
  • Biological: Based on reproductive capabilities.
  • Phylogenetic: Focuses on evolutionary history and genetic ties.

Naming Species

• Binomial Nomenclature: Two-part system naming species (e.g., Homo sapiens).
• Hierarchical Classification: Organisms classified into domains, kingdoms, phyla, classes, orders, families, genera, and species.

Determining Species Relatedness

• Phylogenetic Trees: Illustrate evolutionary relationships, showing common ancestors.
• Evidence Types:
  • Anatomical evidence: Structural similarities across species.
  • Physiological evidence: Shared biological functions.
  • DNA evidence: Comparisons of genetic material.

Cell Types

• Eukaryotic Cells:
  • Possess true nuclei and membrane-bound organelles; can be unicellular or multicellular.
• Prokaryotic Cells:
  • Lack nuclei and organelles; generally simpler and smaller in structure.

Biodiversity Types

• Genetic Diversity: Variation in genes among individuals, enhancing adaptation to environmental changes.
• Species Diversity: Range and abundance of species in specific areas.
• Ecosystem Diversity: Variety of ecosystems present, crucial for ecological health.

Ecosystem Services

• Benefits derived from ecosystems include:
  • Provisioning Services: Goods obtained (e.g., food, water).
  • Regulating Services: Benefits from natural processes (e.g., climate control).
  • Cultural Services: Non-material value (e.g., recreational, aesthetic).
  • Supporting Services: Maintain vital life conditions (e.g., nutrient cycling).

Conservation Biology

• Genetic diversity is critical for resilience to diseases and environmental shifts.
• Conservation strategies include introducing new individuals to populations, exemplified by Florida Panther recovery efforts.

Human Impact on Biodiversity

• Enhanced species diversity increases ecosystem resilience against disturbances.
• Biodiversity is vital for sustaining ecosystem services and overall ecological balance.

Cell Types Comparison

• Prokaryotic Cells vs. Eukaryotic Cells:
  • No true nucleus vs. true nucleus.
  • Generally smaller (0.1 - 5.0 µm) vs. larger (10 - 100 µm).
  • Lack membrane-bound organelles vs. possess them.
  • Simpler structure vs. more complex, variable structures.