Food Webs and Ecological Terms

Food Webs and Food Chains

• Energy is transferred from producers to consumers.
• Arrows in a food chain represent energy transfer.
• Decomposers are the final link in a food chain.
• Producers create their own food using photosynthesis.
• Consumers consume other organisms for food.
  • Omnivores eat both plants and animals.
  • Herbivores eat only plants.
  • Carnivores eat only animals.
  • Insectivores eat only insects.
  • Scavengers eat dead animals and plants.
• Decomposers break down dead organic matter.
• Photosynthesis formula: $CO_2 + H_2O → O_2 + C_6H_{12}O_6$

Ecological Terms

• Individual: One living organism.
• Population: A group of individuals of the same species.
• Community: A group of different populations living together.
• Ecosystem: All communities and their environment (biotic and abiotic).
• Biosphere: All ecosystems.
• Biodiversity: Variety of life in an ecosystem.
• Habitat: An organism's living area.

MRS GREN Notes

• Movement: Moving from one place to another.
• Reproduction: Creating more of the same organism.
• Sensitivity: The ability to perceive and respond to the environment.
• Growth: An increase in size or weight.
• Respiration: The process of converting glucose into energy (ATP).
• Excretion: The elimination of waste products.
• Nutrition: Obtaining food (animals) or producing it (plants).

Cell Structure and Function

• Cell Membrane: A thin, flexible layer that controls what enters and leaves the cell.
• Cytoplasm: Where chemical reactions occur, such as photosynthesis.
• Nucleus: The control center of the cell, containing DNA.
• Mitochondria: The site of ATP production through respiration.

Processes

• Respiration: C₆H₁₂O₆ + O₂ → ATP + H₂O + CO₂
• Photosynthesis: CO₂ + H₂O → C₆H₁₂O₆ + O₂

Environmental Adaptations

• Xerophytes: Adapted to dry environments.
• Hydrophytes: Adapted to wet environments.

Animal Adaptations

• Camouflage: Blending in with surroundings.
• Mimicry: Resembling another animal or object.

Nutrient Cycle

• Decomposers break down dead organic matter, releasing minerals into the soil.
• Plants take up minerals from the soil for growth.
• Dead leaves contribute to the soil's nutrient content.

Disease Caused by a Protozoan

• Malaria: Caused by the protozoan Plasmodium, transmitted by mosquitoes.
• Symptoms: High fever, chills, shaking, sweating, muscle aches, headaches, vomiting.
• Treatment: Prophylactics (preventive medicine) for Plasmodium.

Waterborne Diseases

• Spread through contaminated water.

Disease Caused by a Virus

• HIV/AIDS: Human Immunodeficiency Virus causes Acquired Immunodeficiency Syndrome.
• Management: Healthy lifestyle and ARVs (Antiretroviral Medicines).
• Symptoms: Fever, aches, sore throat, swollen glands.

Disease Caused by Bacteria

• TB (Tuberculosis): A lung infection.
• Treatment: Long-term antibiotics use.
• Symptoms: Coughing blood, fever, weight loss, night sweats.

Micro-organisms

• Unicellular and microscopic.
• Reproduce quickly.
• Found in water, air, soil, and inside/outside living organisms.
• Types:
  • Non-cellular: Viruses (not included in MRS GREN).
  • Monera: Bacteria (included in MRS GREN).
  • Protista: Protozoans and algae (included in MRS GREN).
  • Fungi: Mushrooms, yeasts, and molds (included in MRS GREN).
  • Plantae and Animalia: Larger organisms.