Intro to BIology
DNA, RNA & Genetics
,What Is Biology?
● Biology = study of living things and their
interactions with the environment.
● “Bio” = life; “-logy” = study of.
● Biologists ask how life works — from tiny
cells to big ecosystems.
,Characteristics of Life
All living things share these traits:
● Organization — made of one or more cells (basic unit of life).
● Energy use — need energy to grow, move, and maintain structure (metabolism).
● Homeostasis — maintain stable internal conditions (like temperature, pH, water
balance).
● Growth & development — get bigger or change over time.
● Reproduction — make new organisms (sexually or asexually).
● Response to stimuli — react to environment (light, temperature, touch, etc.).
● Adaptation & evolution — populations change over generations.
, Levels of Biological Organization
Small → Big: 7. Organ system → organs that perform a
common function.
1. Atom → smallest unit of matter.
8. Organism → one living individual.
2. Molecule → atoms bonded together.
9. Population → group of same species.
3. Organelle → parts inside cells (like
mitochondria). 10. Community → different species together.
4. Cell → smallest living unit. 11. Ecosystem → living + nonliving things
interacting.
5. Tissue → group of similar cells.
12. Biosphere → all life on Earth.
6. Organ → tissues working together
(heart, brain).
DNA, RNA & Genetics
,What Is Biology?
● Biology = study of living things and their
interactions with the environment.
● “Bio” = life; “-logy” = study of.
● Biologists ask how life works — from tiny
cells to big ecosystems.
,Characteristics of Life
All living things share these traits:
● Organization — made of one or more cells (basic unit of life).
● Energy use — need energy to grow, move, and maintain structure (metabolism).
● Homeostasis — maintain stable internal conditions (like temperature, pH, water
balance).
● Growth & development — get bigger or change over time.
● Reproduction — make new organisms (sexually or asexually).
● Response to stimuli — react to environment (light, temperature, touch, etc.).
● Adaptation & evolution — populations change over generations.
, Levels of Biological Organization
Small → Big: 7. Organ system → organs that perform a
common function.
1. Atom → smallest unit of matter.
8. Organism → one living individual.
2. Molecule → atoms bonded together.
9. Population → group of same species.
3. Organelle → parts inside cells (like
mitochondria). 10. Community → different species together.
4. Cell → smallest living unit. 11. Ecosystem → living + nonliving things
interacting.
5. Tissue → group of similar cells.
12. Biosphere → all life on Earth.
6. Organ → tissues working together
(heart, brain).
