Defining Species: Biological, Morphological & Phylogenic

• Estimated 30-100 million species exist.

Importance of Identification, Definition, and Naming

• Essential for medical, food, and shelter applications.

Defining Species

• Three primary methods exist for defining species.

Biological Species Concept

• Focuses on the behavior and ability of organisms to produce fertile offspring.
• Advantage: Widely accepted and used in the scientific community.
• Disadvantage: Cannot be universally applied to all cases.

Morphological Species Concept

• Centers on a species' structure, form, and physical appearance, recognizing changes over time.
• Advantage: Simplicity in application.
• Disadvantage: Subjectivity in determining acceptable levels of difference.

Phylogenetic Species Concept

• Emphasizes the evolutionary relationships among species.
• Advantage: Applicable to extinct species.
• Disadvantage: Evolutionary history is not known for all species.

Taxonomy

• The science dedicated to classifying organisms.
• Binomial Nomenclature: Uses a two-part name (Genus species) to identify organisms.
  • Names must be italicized with the genus capitalized and the species in lowercase.

Classification Hierarchy

• Organisms are classified into Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.

Applications of Classification

• Aids in drug discovery and improving crop yields.

Evidence of Species Relatedness

• Anatomical: Physical attributes, like size and shape.
• Physiological: Functional aspects, such as protein production.
• DNA: Genetic material similarities.

Cell Types

• Two primary types: eukaryotic and prokaryotic.

Six Kingdoms

• Plantae, Animalia, Fungi, Protists, Archaea, and Bacteria.
• The first four kingdoms contain eukaryotic organisms, and the last two contain prokaryotic.

Eukaryotic Cells

• Possess a true nucleus and multiple chromosomes.
• Typically 10x larger than prokaryotic cells.
• Primarily multicellular.
• Usually require oxygen.
• Replicate through mitosis.

Prokaryotic Cells

• Lack a true nucleus and have single chromosomes.
• Roughly 1/10 the size of eukaryotic cells.
• Unicellular.
• Some do not require oxygen.
• Replicate through binary fission.
• Lack membrane-bound organelles.

Three Domains of Life

• Eukarya, Archaea, and Bacteria.

Honeybees

• Play a critical role in ecosystems by pollinating flowers and supporting plant (and therefore food chain) reproduction.

Decline in Bee Populations

• Attributed to pesticide overuse and varroa mites.
• Breeding programs have led to decreased genetic diversity.

Biodiversity

• The range of life in a given area, enabling systems to evolve.

Genetic Diversity

• Represents the gene pool within interbreeding populations.
  • A larger gene pool increases species resilience to disease.

Species Diversity

• Refers to the number of species in a specific area.
  • Greater species diversity improves ecosystem adaptability.

Ecosystem Diversity

• Encompasses the variety of ecosystems within a biosphere.

Importance of Biodiversity

• Higher levels of biodiversity equate to healthier ecosystems.
• Vital for providing medicines, food, fuel, water, and oxygen.

Keystone Species

• Species that are crucial for ecosystem health and survival.

Ecosystem Services

• Benefits ecosystems provide, including water, food, and raw materials.

Ecosystem Components

• Biotic: Living elements in an ecosystem.
• Abiotic: Non-living elements in an ecosystem.

Viruses

• Unique biologic entities with both living and non-living characteristics

Attributes of Living Organisms

• Composed of cells.
• Require and utilize energy.
• Produce waste.
• Can reproduce independently.
• Capable of adapting to the environment.

Attributes of Viruses

• Lack cytoplasm.
• Cannot reproduce independently, requiring a host.
• Significantly smaller than bacterial cells.
• Enclosed by a capsid protein.

Virus Classification

• Classified by size and shape of capsid, structure, disease caused, replication method, and nucleic acid type (RNA or DNA).

Lytic Cycle

• Virus attaches to host, injecting DNA/RNA, leading to virus creation, assembly, and host cell destruction to spread the virus.
• (Short Term)

Lysogenic Cycle

• Viral DNA (provirus) integrates silently, replicating with host DNA until activated by triggers, switching to lytic cycle.
• (Long Term)

Viral Diseases in Humans

• Examples include smallpox, chickenpox, and AIDS.

Vaccines

• Injections introduce weakened or partial viruses, training immunity for future infections.

Archaea

• Organisms within this domain thrive in harsh environments.

Bacterial Shapes

• Cocci: Spherical.
• Bacilli: Rod-shaped.
• Spirilli: Spiral.

Bacterial Aggregation

• Staphylococcus: Cluster formation.
• Streptococcus: Linear arrangement of rod-shaped bacteria.

Archaea Metabolism

• Some are methanogenic, producing methane.

Bacterial Metabolism

• Some are photosynthetic, forming the base of food chains.
• Most are mesophiles.

Extremophiles

• Acidophiles thrive in acidic conditions.