Scientists Discover First Animal That Can Survive without Oxygen

Category: Science/Environment


Unlocking Word Meanings

Read the following words/expressions found in today’s article.

  1. parasite / ˈpær əˌsaɪt / (n) – an animal or plant that relies on another animal or plant to survive

    The animal died because of the parasite that lives in its stomach.

  2. devoid of / dɪˈvɔɪd ʌv / (idiom) – completely lacking something

    The room looks so bare; it’s devoid of design.

  3. adapt / əˈdæpt / (v) – to adjust to a different condition or environment

    The foreign exchange student quickly adapted to her new surroundings.

  4. leech / litʃ / (v) – to get resources for survival from others without giving anything in return

    The man leeched off the company’s funds, so the company eventually became bankrupt.

  5. notion / ˈnoʊ ʃən / (n) – an opinion or belief about something

    The new study disproves the notion that sharks are dangerous.


Read the text below.

Scientists discovered the first multicellular animal that does not need oxygen to live.

Studies have shown that multicellular animals on Earth perform mitochondrial respiration, a process that converts oxygen into energy. This process occurs in the mitochondrion, which is known as the cell’s powerhouse.

However, the newly discovered organism called Henneguya (H.) salminicola does not have a mitochondrion, and therefore cannot breathe oxygen. H. salminicola is a 10-celled parasite that lives inside salmon and is related to jellyfish and coral. Salmon become infected with the parasite when they eat worms, which serve as hosts for H. salminicola. Infected salmon have white, oozing bubbles present in their flesh.

According to scientists, H. salminicola’s inability to breathe was discovered accidentally. While assembling the parasite’s DNA, they saw that it did not possess mitochondrial genes, which make respiration possible. Since the environment inside the salmon’s body is mostly devoid of oxygen, the scientists believe that the parasite adapted to its surroundings by dropping its mitochondrial genes.

While it is still unclear to the scientists how the parasite produces energy, they speculate that the parasite could be leeching energy-rich molecules off the salmon to survive.

Lead author Dorothee Huchon said the study can contribute to evolutionary research by challenging the notion that organisms become more complex as they evolve. Furthermore, the scientists expect that they may discover more organisms that do not need oxygen in the future.

Viewpoint Discussion

Enjoy a discussion with your tutor.

Discussion A

• Do you think it’s necessary to conduct further research on H. salminicola? Explain.
• Do you think a lot of animals are still undiscovered? Why or why not?

Discussion B

• Do you find the idea of animals evolving into simpler and less complex creatures alarming or exciting? Discuss.
• Do you think it’s possible for humans to evolve into simpler and less complex creatures? Why or why not?