All living things share these 7 characteristics. It’s easy to remember them with the word "MRS GREN":
M - Movement Living things can move on their own.
Animals walk, run, swim, or fly.
Plants move slowly, like growing toward sunlight.
R - Respiration Living things need energy to stay alive. They get this energy by breaking down food or using sunlight (plants).
S - Sensitivity They can sense and respond to changes in their environment. Example: You shiver when it’s cold, or plants grow roots toward water.
G - Growth All living things grow! A baby grows into an adult, or a seed becomes a big tree.
R - Reproduction Living things make new living things.
Humans have babies.
Plants grow seeds to make more plants.
E - Excretion Living things get rid of waste.
Humans sweat and urinate.
Plants release oxygen as a waste product.
N - Nutrition They need food or nutrients to survive.
Animals eat plants or other animals.
Plants use sunlight, water, and air to make food through photosynthesis.
CLASSIFICATION OF LIVING ORGANISMS
Scientists organize living things into groups to make them easier to study. These groups go from broad (big) to specific (small).
👉 Think of it like this: Imagine sorting things in your room.
Kingdom is like sorting into categories like clothes, books, and toys.
Species is like saying, “This is my favorite T-shirt.”
WHAT IS A SPECIES?
A species is the smallest group in classification.
Members of the same species can mate and have babies that can also reproduce.
Example:
Lions are a species (Panthera leo). Two lions can mate and have cubs.
Humans are a species (Homo sapiens). Two humans can have children.
DICHOTOMOUS KEYS
A dichotomous key is a tool that helps you identify animals, plants, or other organisms .It works like a decision tree where you answer YES or NO (or choose between two options) until you find the name of the organism.
HOW TO USE A DICHOTOMOUS KEY
Start at Step 1 and answer the question.
Based on your answer, go to the next step.
Keep going until you find the correct name of the organism.
EXAMPLE DICHOTOMOUS KEY (FOR BIRDS):
Does the bird have webbed feet?
Yes → Go to Step 2.
No → Go to Step 3.
Does it have a long beak?
Yes → It’s a Pelican.
No → It’s a Duck.
Is the bird colorful and small?
Yes → It’s a Parrot.
No → It’s a Crow.
WHY ARE DICHOTOMOUS KEYS IMPORTANT?
They help scientists and students:
Quickly identify unknown animals, plants, or fungi.
Organize information into simple steps.
What is homeostasis and why is it important for living organisms?
How do living organisms grow and develop over time?
What is the significance of cellular organization in living organisms?
How do living organisms adapt to changes in their environment?
What are the differences between prokaryotic and eukaryotic cells?