THE HIERARCHY OF LIVING ORGANISMS

Anatomy

The study of internal and external structures.

Physiology

The study of how things perform their vital functions.

Gross Anatomy

The study of large-scale structures visible with the unaided eye.

Microscopic Anatomy

The study of structures that cannot be seen without magnification.

Cytology

The study of cells.

Histology

The study of tissue.

Cranial

Direction towards the head.

Caudal

Direction towards the hips or tail.

Chemical Level

The first level of the hierarchy of living organisms, consisting of elements and ions.

Macromolecules

The four major types of molecules in living organisms:lipids, proteins, nucleic acids, and carbohydrates.

Cellular Level

The second level of the hierarchy where life occurs, composed of cells.

Eukaryotes

Organisms whose cells contain nuclei and membrane-bound organelles.

Tissue Level

The third level of the hierarchy, where similar cells group together to form tissues.

Types of Tissue

Muscle, connective, nervous, and epithelial tissues.

Organ Level

The fourth level where two or more types of tissue work together to perform a function.

Organ System Level

The fifth level where organs interact for a common function.

Examples of Organ Systems

Cardiovascular system, which includes the heart and blood vessels.

Organism Level

The sixth level where all organ systems work together to maintain homeostasis.

Homeostasis

The process by which an organism maintains a stable internal environment while adjusting to external conditions.