Difference Between In situ and Ex situ

The main difference between in situ and ex situ is that the in situ refers to the original location whereas the ex situ refers to the off-site. Furthermore, in situ methods are less expensive and less manageable while the ex situ methods are expensive and manageable.

In situ and ex situ are two methods used to describe different biological processes such as bioremediation, and conservation of organisms.

Key Areas Covered

1. What is In Situ
     – Definition, Examples, Importance
2. What is Ex Situ
     – Definition, Examples, Importance
3. What are the Similarities Between In Situ and Ex Situ
     – Outline of Common Features
4. What is the Difference Between In Situ and Ex Situ
     – Comparison of Key Differences

Key Terms

Bioremediation, Conservation, Ecology, Ex Situ, In Situ, Location

What is In Situ

In situ is the term used to describe ‘on-site’. It means locally or in position. This term is used in many fields to describe various processes including biological ones. In biology, in situ refers to the examination in the exact place where the species occurs. As an example, if someone wants to take a photograph of an animal or plant in the wilderness, it is in situ. Here, the living organism has not been moved to another location besides its actual location. Similarly, in cell science, when the cells are examined inside the whole organ, it is called in situ investigation. Here, the cells are intact in the whole organ and under perfusion. On the other hand, the natural occurrence inside the lab is called in vivo. Although in vivo experiments are not carried out in the natural environment, they are performed inside the whole, living organism. In medicine, in situ is used to describe malignant cells in a tumor.

Figure 1: Live Sea Snail, Photographed In Situ

In ecology, we use the term in situ to describe two processes. They are conservation of living organisms and bioremediation. Conservation of living organisms becomes in situ when it is done inside the natural habitat where the organism lives. Ecologists use this type of conservation for larger populations. On the other hand, bioremediation becomes in situ, when the pollutants are treated in the location where they are used to concentrate naturally.

What is Ex Situ

Ex situ is the term used to describe ‘off-site’. It is the exact opposite of in situ and describes things or processes away from the natural location. Therefore, if someone wants to take the photograph of a living organism outside the wild, then it is called ex situ. Also, the examination of cells outside the organ is called ex situ investigation. The common scenario of the ex situ investigation is either donor has been sacrificed by experimentation or it may not perform as well as before. Most of the cell culture experiments are carried out outside the organism in petri dishes. This is called in vitro experiments. This type of in vitro experiments are crucial for the diagnosis of diseases, microbial production of various metabolites such as vaccines, antibiotics, hormones, enzymes, etc. as well as for the recombinant DNA technology experiments.   

Figure 2: Cactus Conserved in a Botanical Garden

In ecology, the best method for the conservation of smaller populations is ex situ conservation. It involves the conservation of living organisms outside their ecological niche. This protects the species from predation and pressure from the environment. There are many methods in ex situ conservation including conservation of embryos, slow growth stages, seeds, pollen, etc. and the conservation of organisms in botanical gardens, zoos or aquariums. When consider bioremediation, it becomes an ex situ process when the pollutants are collected from their natural location for the treatment.

Similarities Between In Situ and Ex Situ

• In situ and ex situ are two phenomena of many biological processes classified based on the location where the process is carried out.
• Both have applications in biology, medicine, ecology, etc.

Difference Between In Situ and Ex Situ

Definition

In situ means in the original place while ex situ means outside the original place.

Significance

In situ methods are carried out on-site such as in the wild while ex situ methods are carried out off-site such as in a laboratory, botanical garden, zoo, or aquarium. Therefore, this is the main difference between in situ and ex situ.

Type of Population

While in situ methods are applicable for large populations, ex situ methods are applicable for small populations.

Experimental Conditions

Another difference between in situ and ex situ is that the experimental conditions are difficult to maintain in in situ methods while experimental conditions can be easily maintained in ex situ methods.

Cost

Also, while in situ methods are less expensive, ex situ methods are expensive.

Equipment and Labor

One other difference between in situ and ex situ is that In situ methods do not require much equipment and it is less labour intensive while ex situ methods require specific equipment and it is labour-intensive.

Area

However, the in situ methods require a large area but the ex situ methods require a small area.

Conclusion

In situ refers to the on-site and it is used to describe methods carried out in the original place. On the other hand, ex situ refers to the off-site and it is used to describe the methods carried out away from the original place. Therefore, the main difference between in situ and ex situ is the type of location where the process is carried out.

Reference:

1. “In Situ.” Wikipedia, Wikimedia Foundation, 11 Sept. 2018, Available Here
2. “Ex Situ – Oxford Reference.” Oxford Reference, Oxford University Press, 16 June 2017, Available Here
3. “Ex Situ Conservation.” Wikipedia, Wikimedia Foundation, 9 July 2018, Available Here

Image Courtesy:

1. “Natica hebraea” By Blenni (Thomas Huelsken) (CC BY-SA 3.0) via Commons Wikimedia  
2. “ueberlingen-Lake-Constance-Botanical-Garden-Cactus-1524158” (CC0) via Max Pixel