Plant Organs and Growth

Plant Organs and Adaptations

• Leaves: absorb energy from sunlight and make the plant's food through photosynthesis
• Stem: transports water and food, supports leaves and flowers
• Roots: hold the plant in place, absorb water and minerals from the soil
• Flowers: produce seeds for plant reproduction

Adaptations of Cacti and Mangroves

• Cacti: no leaves to prevent water loss, spines for protection, make food in green stem, and store water in stem
• Mangroves: roots pointing upwards to collect air, enabling growth in muddy water

Adaptations of Parasitic Plants

• Parasitic plants: don't need leaves, take food and water from other plants

Scientific Inquiry

• How to ask a question: how, why, what
• First step in any experiment: develop a question or problem that can be solved through experimentation
• A testable question: one that can be answered by designing and carrying out an experiment
• Importance of checking evidence: to support or reject an explanation
• If explanation is rejected: suggest a different explanation, test it, and check evidence again
• If explanation accepted: evidence supports the explanation

Historical Evidence

• Van Helmont: 'What are trees made of?' - His explanation: nutrients from soil; Evidence: tree gained 75kg in weight, but only used 0.1kg of soil, rejects his explanation
• Malpighi: 'Do leaves make the food that plants use to grow?' - Evidence: seedling stopped growing after leaves were removed, suggests leaves make nutrients
• Hales: 'Plants take something out of the air' - Evidence: plant took in something from air, lowering pressure, causing water level to rise, but does not support his explanation

Human Skeleton

• The role of the skeleton: helps you move, supports the body, and protects vital organs
• The skull protects the brain
• Vertebral column: protects and supports the spinal cord
• Ribs: support and protect the heart and lung
• Role of the spinal cord: connects the brain to the rest of the body through a bundle of nerves
• A joint: where two bones meet, making the skeleton flexible for movement
• The structure of a joint: cartilage (smooth cushion), synovial fluid (slippery liquid), ligaments (slightly flexible material), and tendon (non-flexible material)