Systems & Models
If scientists want to study how pollution affects a coral reef, how could defining a system boundary help them focus their investigation?
A boundary helps scientists decide what parts of the reef system to study and what to leave out, so they can focus on interactions within the defined area.
Why is the cell membrane important when thinking of a cell as its own system?
The cell membrane controls what enters and exits the cell, regulating matter flow like a system boundary.
Why can plants survive without eating other organisms, while animals cannot?
Plants make their own food using sunlight, water, and carbon dioxide through photosynthesis.
How would the circulatory system be affected if the respiratory system stopped working correctly?
The circulatory system would not have oxygen to deliver to cells.
How does negative feedback help the body maintain stable internal conditions?
It slows or stops change when the body senses something is out of balance.
How could the output of one system component become the input of another?
In a system, the result (output) of one part can be used by another part as an input.
For example, waste from one organism could become food or nutrients for another.
A eukaryotic cell has many membrane-bound organelles, while a prokaryotic cell does not. How might this affect the complexity of tasks each can perform?
Eukaryotic cells can perform more complex functions because they have specialized organelles.
How does vascular tissue make it possible for plants to grow taller than nonvascular plants?
Vascular tissue transports water and nutrients throughout the plant, allowing support and movement of materials.
Why is information processing necessary for survival in animals?
It allows animals to collect information about their environment and respond to it.
Why might positive feedback be useful even though it increases change?
Sometimes reinforcing change is beneficial, such as when the body needs to continue a process.
Why might a scientist choose a conceptual model instead of a physical model when studying matter flow?
A conceptual model can show ideas and interactions more easily than a physical model, especially when the process is hard to physically build or see.
Why is the nucleus important in making sure new cells are identical when cells divide?
The nucleus contains genetic material, so it ensures new cells receive the same instructions.
What would happen to photosynthesis if the leaf’s ground tissue stopped functioning?
The leaf would not be able to support its structure or store materials, disrupting photosynthesis.
If the muscular system didn’t interact with the skeletal system, what movement challenges would occur?
The animal could not move because muscles move the bones.
How do sensory receptors help an animal respond to the environment?
Sensory receptors detect information like pressure, chemicals, or light and start information processing.
If a model leaves out some system parts, how could that affect predictions scientists make?
The model may not accurately show how the system really behaves, causing incorrect explanations or predictions.
A plant cell has a cell wall and a large vacuole. How do these structures support the plant as a system?
The cell wall gives structure and support; the large vacuole stores materials and helps maintain shape.
How does the shoot system depend on the root system, and how does the root system depend on the shoot system?
The root system absorbs water and nutrients; the shoot system makes food through photosynthesis and transports it to the roots.
Why does the heart require multiple tissue types (muscle, nervous, epithelial) instead of just one?
Different tissues perform different functions — movement, control, and protection.
If an animal could sense information but not store memories, how might behavior change?
The animal could not learn from experiences and would repeat behaviors without improvement.
Imagine a natural system where matter enters but no matter leaves. What could that reveal about how the system is functioning?
It may show the system is collecting matter and not releasing output, meaning the system could become unbalanced or change over time.
How does the structure of mitochondria or chloroplasts relate to its function?
Mitochondria convert stored energy into usable energy, and chloroplasts carry out photosynthesis to make food.
If stomata stayed open all the time, how would that affect the plant’s ability to maintain water levels?
The plant would lose too much water because stomata allow water to exit.
How do the digestive and excretory systems work together?
The digestive system breaks down food to get nutrients, and the excretory system removes liquid wastes.
Explain how a stimulus leads to a behavior using the steps: sense → process → respond.
Sensory receptors sense the stimulus, the nervous system processes it, and the body responds with a behavior.