Complexity of Life - Detailed Notes

COMPLEXITY OF LIFE

Cells are the basic unit of life.
Cells are the smallest components that constitute a living organism.
Organisms can be:
- Unicellular: Made of one cell.
- Multicellular: Made of multiple cells.
Cells contain organelles, which are special molecules that perform specific functions to keep the cell alive.

A cell is the smallest functional unit capable of performing life's tasks.
Living organisms can be single-celled or composed of numerous cells.
In multicellular organisms, cells are specialized and depend on each other for survival.
The specialization and interdependence of cells leads to a hierarchical organization characterized by structure and function:
- CELL: The basic unit of life.
- TISSUE: A group of specialized cells working together for a specific function.
- ORGAN: A distinct structure made of different tissues that perform a specific function.
- ORGAN SYSTEM: A collection of organs that carry out specific functions within an organism.
- ORGANISM: A living entity that performs all life functions.

Tissues are formed when cells combine.
In biology, a tissue represents a cellular organizational level between cells and a complete organ.
A tissue consists of similar cells performing a specific function.
Example: Blood, which consists of red blood cells, white blood cells, platelets, and plasma.

Organs are formed when tissues combine.
An organ is a group of tissues in a living organism adapted to perform a specific function.
In higher animals, organs are grouped into organ systems.
Example: The esophagus, stomach, and liver are organs of the digestive system.

Reproductive structures:
- Function to make more plants.
- Include flowers, fruit, cones, and seeds.
Leaves:
- The primary site of photosynthesis.
Stems:
- Support and elevate the leaves.
- Transport water and nutrients between roots and shoots.
- Store water and nutrients.
Roots:
- Anchor the plant.
- Absorb minerals and water.
- Store nutrients.

An organ system is formed when organs work together.
Organs carry out related processes and functions to keep an organism alive.
Example: The heart and blood vessels work together to form the circulatory system.