Characteristics of Life
A living thing that carries out basic life functions is called what?
An organism.
What is the term for an organism that makes its own food?
Autotroph.
What is the term for maintaining a balanced internal environment?
Homeostasis.
hat characteristic of life involves an increase in cell size or the number of cells?
Growth
What is a change in an organism's environment that causes a response called?
A stimulus
Explain the difference between a unicellular organism and a multicellular organism.
A unicellular organism consists of one cell, while a multicellular organism consists of many cells.
A mushroom obtains nutrients from organic material rather than making its own food through photosynthesis. Is it an autotroph or a heterotroph? Explain.
Heterotroph. It obtains nutrients from other organisms or organic material.
What are three conditions inside the human body that can fluctuate but must remain within a balanced range to maintain homeostasis?
Body temperature, heart rate, and blood sugar levels
A bacterium consists of one cell that carries out all its basic life functions. What term describes this organism, and how does it differ from a human?
The bacterium is unicellular. A human is multicellular and has many cells with different structures and functions.
A houseplant grows toward a nearby window. Identify the stimulus and explain the plant's response.
Light is the stimulus. The plant responds by growing toward the light.
A tree has roots, a trunk, branches, and leaves that perform different jobs. Which characteristic of life does this demonstrate, and why?
Organization. The tree has different structures that work together to perform necessary functions.
Explain how photosynthesis allows a green plant to obtain energy. Use the terms autotroph, sunlight, and glucose.
A plant is an autotroph that uses energy from sunlight to produce glucose through photosynthesis.
A person's body temperature changes during the day but remains within a normal range. Use the term dynamic equilibrium to explain why this does not necessarily mean homeostasis has failed.
Dynamic equilibrium means conditions can fluctuate while the system remains balanced overall. Small temperature changes can occur while the body continues to maintain homeostasis.
Explain the difference between growth and development. Give an example of each.
Growth is an increase in size or cell number. Development involves changes as an organism matures, such as a caterpillar developing into a butterfly.
A student touches a cold object and quickly pulls their hand away. Explain how this demonstrates the characteristic of responding to stimuli. Identify the stimulus and response.
The cold temperature is the stimulus, and pulling the hand away is the response. The organism detects and reacts to a change in its environment.
A student claims that blood is an organism because it comes from a living human. Explain why this claim is incorrect using the term organism.
Blood is part of an organism, but it does not exist independently and carry out all the basic life functions of an organism.
An animal eats food, breaks it down into simpler substances, and removes the parts it cannot digest. Identify and describe the three processes in the correct order.
Ingestion is taking in food; digestion breaks food down into simpler substances; egestion removes undigested material.
On a hot day, a student begins sweating. Explain the sequence of events that helps maintain homeostasis. Include regulation, evaporation, and body temperature.
The body uses regulation to produce sweat. As sweat evaporates from the skin, it removes heat, helping lower body temperature and maintain homeostasis.
Compare sexual and asexual reproduction. Include the number of parents involved and whether the offspring are genetically identical.
Sexual reproduction involves the fusion of egg and sperm cells and produces genetically varied offspring. Asexual reproduction involves one parent and, as described in the lesson, produces genetically identical offspring.
In a population of insects, some have coloring that helps them blend into their surroundings. Explain how this trait could be an adaptation.
The coloring may help the insects avoid predators. If insects with this trait survive and reproduce more successfully, the trait may become more common over generations.
A fallen leaf came from a living tree, but a rock has never been alive. Classify each as biotic or abiotic and explain the difference.
The fallen leaf is biotic because it came from something living. The rock is abiotic because it has never been alive.
Both a green plant and a human need energy to grow and repair their bodies. Compare how each obtains the materials and energy needed for these processes. Use autotroph, heterotroph, photosynthesis, and nutrition.
A plant is an autotroph that uses photosynthesis to make glucose using sunlight, water, and carbon dioxide. A human is a heterotroph who obtains nutrients by eating food. Both use energy and materials for growth and repair.
Regarding your Characteristics of Life Presentation, how did your specific organism maintain a balanced internal environment?
Student Answers will vary
A student says, “An organism only needs to grow to demonstrate that it is alive.” Explain why this reasoning is incomplete. Use at least three other characteristics of life in your response.
Growth alone is not enough because some nonliving things can increase in size. Living things also have cellular organization, use energy, respond to stimuli, maintain homeostasis, reproduce, and adapt over generations.
A population of animals lives in an environment that becomes colder over many generations. Some animals have inherited traits that help them survive in the colder conditions. Explain how an adaptation can become more common in the population. Use the terms adaptation, survival, reproduction, and generations.
An inherited adaptation that improves survival in colder conditions may allow animals with that trait to reproduce more successfully. They pass the trait to offspring, and it may become more common over many generations.