Bio

Classification and Biodiversity

• Classification: A method to group living organisms based on their characteristics. It helps in understanding the variety of living things, their evolution, and relationships.

• Descriptive Groups of Organisms:

  • Plants:
  • Flowering plants
  • Non-flowering plants (e.g., ferns, mosses)
  • Animals:
  • Vertebrates (have a backbone)
  • Invertebrates (e.g., insects)

• Why Classify Organisms?

  • To organize biological diversity
  • To study evolutionary relationships
  • To identify organisms systematically

• Classification Based on:

  • Morphological features (size, shape, structure)
  • DNA analysis

• Five Kingdom Classification:

  • Bacteria: Single-celled organisms
  • Plants: Multicellular organisms that perform photosynthesis
  • Fungi: Decomposers, non-photosynthetic organisms
  • Animals: Multicellular, heterotrophic organisms

• Common Names vs. Scientific Names:

  • Common names vary by region and can be misleading.
  • Scientific names (binomial nomenclature) are universal: e.g., Homo sapiens for humans, Erinaceus europaeus for hedgehogs.

Adaptations

• Morphological adaptations: Physical characteristics that help survival (e.g., ear size, coat color).

  • Example: Arctic fox vs. Fennec fox
    eradicator:

  • Arctic fox:

    • Small ears (reduce heat loss)
    • White fur (camouflage in snow)

  • Fennec fox:

    • Large ears (heat loss)
    • Sandy coat (camouflage in desert)

• Behavioral adaptations: Actions that aid survival (e.g., nocturnal behavior to avoid heat).

Population Size

• Definition: The number of individuals of one type of plant or animal in an ecosystem.

• Factors Affecting Population Size:

  • Competition for resources
  • Number of predators
  • Disease
  • Pollution

• Types of Competition:

  • Interspecific competition: Between different species
  • Intraspecific competition: Within the same species

Biodiversity & Conservation

• Biodiversity: The variety of life in the world, refers to species richness and abundance. Essential for:

  • Food resources
  • Industrial materials
  • Medicines
  • Human well-being

• Threats: Habitat destruction due to agriculture, industry, and urban development leads to extinction.

• Conservation Efforts:

  • CITES: Prevents illegal trade of endangered species.
  • SSSI: Protects rare habitats.
  • National Parks: Conserves natural beauty and biodiversity.
  • Captive breeding programs (e.g., zoos).
  • Seed banks maintain genetic biodiversity.

Studying Ecosystems

• Sampling Techniques:

  • Quadrats to measure plant cover.
  • Random sampling to avoid bias.

• Use of Transects:

  • Measure distribution and frequency of organisms along a line using quadrats.

Measuring Animal Populations

• Capture-Recapture Method:
  • Equation: N = \frac{M C}{R}
  • Where:
  • N = total population estimate
  • M = marked individuals returned
  • C = total captured in second sample
  • R = captured individuals that were marked

Biological Control

• Using natural predators to control pests instead of chemical pesticides (e.g., wasps controlling whiteflies).

• Advantages: Specific to target pests, no pesticide resistance.

• Disadvantages: Delay in effectiveness and potential introduction of new pests.

Alien Species and Invasive Species

• Definition: Alien species are organisms introduced into a region where they are not native.

  • Example: Japanese Knotweed in Britain.

• Effects: Alien species can outcompete, prey on, or carry diseases to native species.

Cell Division and Stem Cells

• Importance: Cell division essential for growth and repair; uncontrolled division leads to cancer.

• Types of Cell Division:

  • Mitosis: Produces two identical cells for growth and repair.
  • Meiosis: Produces gametes for sexual reproduction.

• Stem Cells: Unspecialized cells with potential to differentiate into specialized cells.

  • Sources: Adult stem cells (bone marrow), embryonic stem cells (IVF leftovers).

DNA and Inheritance

• Structure of DNA:

  • Composed of two strands forming a double helix; contains bases: Adenine (A), Thymine (T), Cytosine (C), Guanine (G).
  • Base pairing: A-T, C-G.

• Genetic Profiling: Technique for analyzing DNA for identification.

• Inheritance: Traits passed from parents to offspring (alleles, genotype, phenotype).

  • Use of Punnett squares for predicting inheritance patterns.

Human Genome and Evolution

• Natural Selection: Process where organisms better adapted to their environment tend to survive and produce more offspring.
• Variation: Caused by genetic factors and environmental interactions.

Response and Regulation

• Homeostasis: Maintaining internal stability (e.g., temperature regulation).

• Reflex Actions: Fast, automatic responses controlled by the nervous system.

Role of Kidneys in Homeostasis

• Functions: Regulate water content, remove waste (urea, salts).
• Nephron: Unit of the kidney that filters blood and forms urine.
  • Filtration: Occurs in the glomerulus.
  • Reabsorption: Useful substances return to the blood.

Micro-organisms and their Applications

• Culturing Bacteria: Used to study presence and effects of microbes (e.g., using agar plates).
  • Antibiotics: Naturally derived substances used to kill bacteria.
  • Food preservation relies on temperature control to inhibit bacterial growth.

Disease, Defence, and Treatment

• Pathogens: Micro-organisms that cause disease (e.g., bacteria, viruses).

• Immune Response: Body's mechanisms to defend against pathogens.

• Vaccination: Introduces antigens to stimulate the immune response and produce memory cells.

• Antibiotic Resistance: Result of overuse of antibiotics leads to bacteria that can survive treatment.

Key Concepts:

• Public Health: Importance of vaccines and lifestyle choices in health management.
• New Medicine Development: Includes stages for testing efficacy and safety before public use.