In-Depth Notes on Classification, Biodiversity, and Related Concepts

Classification and Biodiversity

Classification - Descriptive Groups

• Definition: Classification means organizing living organisms into groups based on similarities.

• Main Groups:

  • Plants: Includes:

  • Flowering plants (e.g., those that produce flowers)

  • Non-flowering plants (e.g., ferns and mosses)

  • Animals: Divided into:

  • Vertebrates (with backbone)

  • Invertebrates (without backbone, e.g., insects)

Importance of Classification

• Classification helps understand:

  • The variety of living organisms

  • Evolutionary relationships and changes over time

Classification Systems

• Five Kingdom Classification based on morphological features:

  1. Bacteria: Single-celled organisms

  2. Plants

  3. Fungi

  4. Animals

• Common names for organisms can be misleading as they are often based on appearance.

Naming Organisms

• Scientific Naming: Uses a binomial naming system by Carl Linnaeus; names are in Latin.

  • Each organism is given a two-part name (Genus and species), e.g., Homo sapiens (humans), Erinaceus europaeus (hedgehog).

Example of Classification

Adaptations

• Organisms develop morphological and behavioral adaptations for survival.

  • Example - Foxes:

  • Arctic Fox: Found in Arctic, has a thicker coat for insulation.

    • Features:

    • Body mass: 6.5-17.0 kg

    • Coat color: White in winter

  • Fennec Fox: Found in deserts with a sandy cream coat for camouflage.

    • Features:

    • Ear length: 10-15 cm (larger ears help in heat loss)

Population Size

• Definition: The number of individuals of a particular species in an ecosystem.

• Influenced by:

  • Competition for food and water

  • Number of predators

  • Disease and pollution

Biodiversity

• Definition: Variety of different species in an area and the number of individuals within those species.

• Importance of biodiversity includes food resources, potential foods, industrial materials, new medicines, and overall human well-being.

Protecting Endangered Species

• Methods of Protection:

  • CITES: Prevents trade in endangered species.

  • SSSIs: Protects rare habitats or species.

  • Captive Breeding Programs: Increase numbers of rare species for re-introduction.

  • National Parks: Protects areas due to natural beauty and biodiversity.

  • Seed Banks: Maintains genetic diversity of plants.

  • Local Conservation Schemes: Initiatives by local authorities to enhance biodiversity.

Studying Ecosystems

• Methods for assessing species populations often involve sampling techniques.

  • Quadrat Sampling: Used to assess plant populations.

  • Transects: Used to study distribution of species in a habitat.

Measuring Movement in Animal Populations

• Capture-Recapture Method: Assesses the population by marking and recapturing animals, following a formula:
  N = rac{MC}{R}

• Where:

  • N = total population estimate

  • M = marked individuals captured first

  • C = individuals captured second

  • R = recaptured marked individuals in second sample.

Biological Control of Pests

• Definition: Using natural predators/parasites to manage pest populations.

• Example: Use of wasps to control whitefly in greenhouses, offering a targeted approach without harming beneficial insects.

Alien Species

• Definition: Organisms introduced into new environments where they are not native; may disrupt ecosystems.

• Example: Japanese knotweed, an invasive species in Britain, poses significant ecological risks due to lack of natural predators.

Cell Division and Stem Cells

Overview of Cell Division

• Cells divide for growth and reproduction.

• Mitosis vs. Meiosis:

  • Mitosis: Produces 2 identical cells for growth/repair.

  • Meiosis: Produces 4 genetically varied gametes (sperm/eggs).

Mitosis Explained

• Occurs in somatic cells. Each new cell maintains the original chromosome number (e.g., humans have 46 chromosomes).

Meiosis Explained

• Occurs in germ cells, reducing chromosome number by half, leading to genetic diversity through recombination.

Stem Cells

• Definition: Undifferentiated cells capable of turning into other cell types.

• Sources:

  • Adult Stem Cells: Found in tissues (e.g., bone marrow).

  • Embryonic Stem Cells: Derived from fertilized embryos.

• Uses: Potential for medical treatments (e.g., repairing damaged tissue).

DNA and Inheritance

Structure of DNA

• DNA is structured as a double helix composed of sugar, phosphate, and bases (A, T, C, G).

• Base pairing rules: A-T, C-G.

Genetic Profiling

• Used to compare genetic similarities among individuals.

• Applications in forensic science, paternity cases, and disease studies.

Patterns of Inheritance

• Terms to remember: gene, allele, genotype, phenotype, dominant/recessive traits.

• Example: Pea plants studied by Gregor Mendel demonstrate basic principles of inheritance via Punnett squares.

Response and Regulation

The Nervous System

• Comprised of receptors, neurones, and the brain; it processes stimuli and coordinates responses.

• Reflex Actions: Fast, automatic reactions to stimuli; involve a reflex arc.

Homeostasis

• Maintaining stable internal conditions (e.g., temperature, glucose levels).

• Roles of Hormones: Insulin for blood sugar regulation, ADH for water balance.

Diabetes

• Type 1: Insulin deficiency; Type 2: Insulin resistance. Management includes lifestyle adjustments and medications.

Role of the Kidneys in Homeostasis

Kidney Functions

• Maintaining water balance, filtering waste products from blood.

• Structure: Includes renal artery, renal vein, nephrons (functional unit).

Nephron Functioning

• Ultrafiltration: Filters blood under pressure to form urine.

• Reabsorption: Useful substances like glucose and water are reabsorbed back into circulation.

Treatments for Kidney Failure

• Dialysis: Filters blood artificially when kidneys fail.

• Transplant: Replacing a failed kidney with a healthy one.

Micro-organisms and Their Applications

Bacteria Growth

• Techniques for culturing bacteria include using aseptic methods to prevent contamination.

Antibiotics

• Used to treat bacterial infections but ineffective against viruses.

• Antibiotic Resistance: Can develop from overprescribing or misuse of antibiotics.

Disease, Defence and Treatment

Immune Response

• Body has multiple defenses against pathogens, including skin barrier and white blood cell activities.

• Vaccination: Introduces antigens to build immunity against diseases by stimulating antibody production.

Monoclonal Antibodies

• Produce specific antibodies used for diagnosis and treatment of diseases.

• Applications include cancer therapy, diagnostics, and disease monitoring.