Q4

WEEK 1: Reproduction and Development of Plants and Animals

The Importance of Reproduction

  • Procreation: Necessary for the continuous existence of organisms.

  • Genetic Variation: Mixing of genetic materials improves quality and leads to diversity among individuals.

  • Chemical Replication: Primitive chemical systems could replicate leading to reproduction.

Types of Reproduction

Asexual Reproduction

  • Found in unicellular organisms where one cell reproduces itself (identical offspring).

  • In multicellular organisms, it involves growth and regeneration.

  • Some multicellular organisms may reproduce asexually (e.g., vegetative reproduction in plants).

Sexual Reproduction

  • Involves fusion of male and female gametes to form a zygote.

    • Fertilization: The fusion of the nuclei of gametes.

  • Examples in plants:

    • Ferns: Reproduce through spores (asexual reproductive cells).

    • Flowering plants: Have both male and female parts.

Plant Reproductive Structures

  • Gynoecium: Female reproductive parts (stigma, style, ovary).

  • Androecium: Male reproductive parts (stamens, pollen grains contain male gametes).

  • Pollination Process: Involves pollen grain growth into a tube that delivers male gametes to ovules.

  • Seed Formation: Result of fertilization; ovules develop into seeds, ovary into fruit.

    • Variability in ovule numbers (e.g., avocado vs. kiwifruit).

Reproductive Traits in Organisms

  • Both plants and animals utilize color display for reproduction (e.g., bright flowers to attract pollinators, peacocks displaying for mates).

  • Sexual Selection: Males compete for female attention, influencing gene transfer.

  • Differences in fertilization methods:

    • Animals: Require physical proximity.

    • Plants: Often require vectors (insects/birds) for pollen transfer.

WEEK 2: Nutrient Procurement and Processing

Nutrition of Plants and Animals

  • Energy Requirement: Essential for movement, respiration, digestion.

  • Nutrition Definition: The process of obtaining food necessary for health and growth.

Modes of Nutrition

A. Autotrophs

  • Photoautotrophic: Use sunlight to synthesize food (e.g., plants).

  • Chemoautotrophic: Use chemical processes to create organic substances.

B. Heterotrophs

  • Cannot manufacture their own food; obtain energy from others.

    • Parasitic Nutrition: Depend on hosts (e.g., leeches, tapeworms).

    • Insectivorous Plants: Trap insects for nutrients (e.g., Venus flytrap).

    • Saprophytic Nutrition: Derive nutrition from decaying matter (e.g., fungi).

    • Holozoic Nutrition: Ingest solid or liquid food (categorised into herbivores, carnivores, omnivores).

Nutritional Requirements

  • Plants: Require water, carbon dioxide, macronutrients (e.g., C, H, O, N) and micronutrients (e.g., Fe, Zn).

  • Absorption: Through specialized structures (e.g., root hairs, mycorrhizae).

Digestive Processes in Animals

  1. Ingestion: Act of eating and breaking down food.

  2. Digestion: Breakdown into smaller molecules for absorption.

  3. Absorption: Nutrients taken up by cells.

  4. Elimination: Removal of undigested materials.

Human Digestive System

  • Components include oral cavity, pharynx, esophagus, stomach, small and large intestines.

  • Key Functions:

    • Stomach: Stores and breaks down food.

    • Small Intestine: Major site of digestion and absorption.

    • Large Intestine: Concentrates and stores waste.

WEEK 3: Gas Exchange and Transport

Gas Exchange in Organisms

  • Organisms require oxygen for energy production and must expel carbon dioxide.

  • Respiration vs. Photosynthesis:

    • Respiration: Oxygen intake and carbon dioxide release.

    • Photosynthesis: Plants convert CO2 and water into carbohydrates, releasing oxygen.

Respiratory Surfaces

  • Must be moist, large enough for adequate gas exchange.

  • Different organisms utilize various respiratory structures:

    • Invertebrates: Cell membranes, integumentary surfaces, gills.

    • Vertebrates: Lungs, internal and external gills.

Ventilation Mechanisms

  • Movement of respiratory medium (air/water) over gas exchange surfaces (e.g., gills in fish).

Plant Gas Exchange

  • Stomata and lenticels facilitate gas exchange in plants. Respiration occurs during both day and night.

WEEK 4: Excretion and Immune Responses

Excretion in Animals

  • Functions: Elimination of waste; renal system includes kidneys, ureters, bladder.

  • Kidney Functions: Filtration, reabsorption, secretion to maintain homeostasis.

Immune Responses

  • Innate Immunity: First response, nonspecific defenses like phagocytosis.

  • Adaptive Immunity: Specific defense involving B and T cells, antibodies production.

WEEK 5: Feedback Mechanisms

Homeostasis

  • Definition: Stability in the internal environment.

  • Feedback Mechanisms:

    • Negative Feedback: Reverses changes to maintain equilibrium.

    • Positive Feedback: Enhances changes for certain processes (e.g., labor contractions).

Regulation of Body Temperature

  • Hypothalamus regulates temperature through vasodilation or vasoconstriction based on conditions.

WEEK 6: Water Regulation and Osmoregulation

Blood Pressure Regulation

  • Mechanisms: Baroreceptors monitor blood pressure; kidneys regulate blood volume affecting pressure.

Osmoregulation in Animals and Plants

  • Animals maintain osmotic balance through kidneys, while plants use stomata.

  • Different strategies employed by aquatic organisms (osmoconformers vs. osmoregulators).

WEEK 7: Glucose Regulation

Importance of Glucose

  • Central source of energy; tightly regulated by insulin and glucagon.

  • Dysregulation leads to diabetes, impacting multiple organ systems.

Hormonal Regulation

  • Insulin: Lowers glucose levels by facilitating uptake by cells.

  • Glucagon: Raises glucose levels by promoting glycogen breakdown in the liver.

Diabetes Types

  • Type 1 Diabetes: Autoimmune destruction of insulin-producing cells.

  • Type 2 Diabetes: Insulin resistance leading to elevated glucose levels.