Levels of biological organisation

Levels of biological organisation

This animation presents levels of biological organisation from the level of the individual organism to the level of cells.

Biology

Keywords

organ, tissue, cell, organism, organ system, cell organelles, mitochondrion, endoplasmic reticulum, Golgi apparatus, vesicle, cell membrane, cytoplasm, cytoskeleton, liver, liver cell, living organism, biology

Related items

Scenes

Organism

Organ system

  • esophagus
  • stomach - Proteins are digested in this organ. Gastric juice is strongly acidic.
  • small intestine - Proteins, carbohydrates and lipids are digested here. The absorption of digested nutrients takes place here.
  • colon - It is involved in the absorption of minerals and water. Certain bacteria living here produce vitamins B and K.
  • rectum
  • liver - It plays an important role in detoxification and produces bile, which aids the digestion of lipids.
  • pancreas - It produces pancreatic juice, which digests lipids, carbohydrates and proteins in the small intestine. It also secretes insulin hormone, which acts to lower the blood glucose level.

Organ

  • lobes
  • connective tissue wall

Cell

  • mitochondrion - The cell's power station: it produces ATP by breaking down organic molecules. ATP is the primary energy-transfer molecule in the cell.
  • endoplasmatic reticulum - A complex, interconnected network of membranes inside the cell. It plays an important role in protein synthesis, protein processing, lipid synthesis and the breaking down of certain substances.
  • nucleus - It contains chromatin, a complex of DNA and proteins. The cells of animals, plants and fungi are eukaryotic, that is, they contain a nucleus enclosed by membrane. Prokaryotic cells (bacteria) do not have a membrane-bound nucleus, their DNA is found in the cytoplasm.
  • Golgi apparatus - It plays an important role in protein processing.
  • vesicle - Substances within the cell are transported wrapped in membrane bubbles or vesicles. One type of vesicles is the lysosome, in which certain substances are digested and waste is broken down.
  • cell membrane - A lipid membrane that encloses the cell. It contains embedded proteins and carbohydrates.
  • cytoplasm
  • cytoskeleton - It plays important roles in the positioning and movement of vesicles and organelles, and provides animal cells - which do not have cell walls - with structure and shape.

Tissue

Animation

  • esophagus
  • stomach - Proteins are digested in this organ. Gastric juice is strongly acidic.
  • small intestine - Proteins, carbohydrates and lipids are digested here. The absorption of digested nutrients takes place here.
  • colon - It is involved in the absorption of minerals and water. Certain bacteria living here produce vitamins B and K.
  • rectum
  • liver - It plays an important role in detoxification and produces bile, which aids the digestion of lipids.
  • pancreas - It produces pancreatic juice, which digests lipids, carbohydrates and proteins in the small intestine. It also secretes insulin hormone, which acts to lower the blood glucose level.
  • lobes
  • connective tissue wall
  • mitochondrion - The cell's power station: it produces ATP by breaking down organic molecules. ATP is the primary energy-transfer molecule in the cell.
  • endoplasmatic reticulum - A complex, interconnected network of membranes inside the cell. It plays an important role in protein synthesis, protein processing, lipid synthesis and the breaking down of certain substances.
  • nucleus - It contains chromatin, a complex of DNA and proteins. The cells of animals, plants and fungi are eukaryotic, that is, they contain a nucleus enclosed by membrane. Prokaryotic cells (bacteria) do not have a membrane-bound nucleus, their DNA is found in the cytoplasm.

Narration

The levels of biological organisation include levels above and below the level of the individual organism. The levels above the level of organisms are populations, communities, biomes and the biosphere. These levels are studied in the field of ecology. This animation shows the levels below the individual organism through an example.

An individual, that is, an organism, is built up of organ systems. The main organ systems in humans are the nervous system, the endocrine system, the reproductive system, the musculoskeletal system, the cardiovascular system, the excretory system, the respiratory system and the digestive system.

Organ systems consist of separate organs. For example, one of the most important organs in the digestive system is the liver. It plays an important role in detoxification, the storage of nutrients in the body and the production of bile, which aids in the digestion of lipids.

Organs consist of tissues. The liver is organised into hexagonal lobules. A vein crosses each lobule at the centre, while there is an artery, a vein and a bile duct that runs along each of its corners. Besides liver tissue, the liver also contains other types of tissues, such as blood tissue, epithelial tissue and connective tissue. Generally, organs contain several types of tissue.

Tissues are made up of cells. Liver cells, called hepatocytes, are rich in smooth endoplasmatic reticulum, which plays an important role in removing toxins from the blood. Genetic material is stored in the cell nuclei. Other important cell organelles include the mitochondria, which are responsible for providing energy for the cell. Not all living organisms contain these five levels of organisation. For example, parazoa and thalloid plants have no tissues; therefore, they have no organs either.

Related items

Animal and plant cells, cellular organelles

Eukaryotic cells contain a number of organelles.

Connective tissues

Connective tissues include loose and dense connective tissues, adipose tissue, blood, tendon and bone tissue.

Human body (female)

This animation introduces the most important systems of the human body.

Human body (male)

This animation introduces the most important organ systems of the human body.

Muscle tissues

The three types of muscle found in the human body are the smooth, the striated and the cardiac muscle.

Neurons, nervous tissue

Neurons are cells specialised for transmitting electric signals.

Organisation of genetic material

Eukaryotic cells with nuclei measuring only a few micrometres may contain nearly 2 metres of DNA, coiled multiple times.

The anatomy and functions of the liver

The liver is a vital organ that plays an important role in the digestion of fats, detoxification and metabolism.

The upper gastrointestinal tract

During swallowing food travels from the mouth cavity into the stomach.

Types of surface epithelium

Surface epithelia cover the external and internal surfaces of the body

What is the human body composed of?

This scene presents the basic components of the human body.

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