Biofluorescence 

26 Oct Biofluorescence 

This article covers “Daily Current Affairs” and the topic details “Biofluorescence”. This topic has relevance in the “Ecology and Environment” section of the UPSC CSE exam.

For Prelims:

What is Biofluorescence?
Animals showing Biofluorescence?

Why in the news?

New research has suggested that fluorescence, a phenomenon where certain animals can emit striking and vibrant light, is quite common in mammals. 

Biofluorescence 

• Fluorescence is the process by which a substance absorbs light of one wavelength and emits light of a longer wavelength. 
• Biofluorescence is the emission of light by living organisms when they absorb light of a higher energy wavelength and emit it at a lower energy wavelength. This process is similar to fluorescence, but it occurs in living organisms.

How does fluorescence work in animals?

• Fluorescence is caused by fluorescent molecules in the animal’s body. These molecules can be found in various tissues, including skin, fur, feathers, and bones. 
• When a fluorescent molecule absorbs light of a certain wavelength, it becomes excited. When the molecule returns to its ground state, it releases the excess energy as light of a longer wavelength.
• The colour of the light emitted depends on the type of fluorescent molecule and the wavelength of light that it absorbs. For example, many fluorescent animals emit green light, but some can emit blue, red, or even yellow light.

Bioluminescence 

• Bioluminescence is the production of light by a living organism without generating heat. It is a form of chemiluminescence, where chemical energy is converted into light. 
• This happens when an enzyme called luciferase reacts with a substrate called luciferin. The luciferin molecule becomes excited and releases its energy through light.
• The main difference between bioluminescence and biofluorescence is the source of light. 
  • In bioluminescence, the light is produced by a chemical reaction within the organism. 
  • In fluorescence, the light is produced by the absorption of light from an external source.
• Most bioluminescent life forms inhabit the ocean, encompassing various marine species like fish, bacteria, and jellyfish. Nevertheless, certain bioluminescent creatures, such as fireflies and fungi, can also be found on land.

Why do animals fluoresce?

Scientists are still learning about the functions of fluorescence in animals. However, it is thought to have a variety of purposes, including:

• Communication: Some animals use fluorescence to communicate with each other. For example, some fish use fluorescent signals to attract mates or warn of rivals.
• Camouflage: Fluorescence can also be used for camouflage. For example, some corals fluoresce to blend in with their surroundings and avoid predators.
• Sunscreen: Fluorescence can also act as a sunscreen. For example, some animals fluoresce to absorb harmful UV radiation.
• Prey attraction: Some animals use fluorescence to attract prey. For example, some anglerfish have fluorescent lures that they use to attract smaller fish.

Examples of fluorescent animals:

• Invertebrates: Coral, jellyfish, sea anemones, scorpions, spiders
• Reptiles: Chameleons, geckos, iguanas
• Amphibians: Frogs, toads
• Fish: Anglerfish, clownfish, parrotfish, scorpionfish
• Birds: Toucans, puffins, parrots
• Mammals: Opossums, wombats, flying squirrels

Fluorescence in mammals:

• Fluorescence in mammals was thought to be rare until recently. However, new research has shown that fluorescence is quite common in mammals. 
• For example, a 2023 study found that over 90% of the mammal species studied were fluorescent in some way.

Sources: Fluorescence: making animals glow (thehindu.com)

Download plutus ias current affairs eng med 26th Oct 2023

Q1. With reference to Biofluorescence, consider the following statements: 

1. Fluorescence is the process by which a substance absorbs light of one wavelength and emits light of a shorter wavelength. 
2. Fluorescence is caused by fluorescent molecules in the animal’s body. 

Which of the statements given above is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2 

(d) None 

Check Answer

Q2. Consider the following:

1. Chameleons
2. Frogs
3. Parrotfish
4. Parrots

How many of the abovementioned animals show Biofluorescence ?

(a) Only one 

(b) Only two 

(c) Only three 

(d) All Four 

Check Answer

Gaurav N