Question

Which one of the following is a living fossil?
A. Spirogyra
B. Ginkgo
C. Moss
D. Saccharomyces

Answer 1

These are the species that are an extant taxon that closely resembles organisms that are known only from the fossil record. These are commonly of species-poor lineage and exhibit stasis (also known as bradytely) over geologically long time scales.

Complete Answer:
Living fossils can be found in both animals as well as in plants. Living fossils exhibit two main characteristics. These are:
- Living organisms that are members of taxa have remained recognizable in the fossil record over a geologically long time scale.
- They should have little morphological divergence whether from an early member of a lineage or among their extant (living) species.
- Apart from these two, one more characteristic can be noted that they have little taxonomic diversity.
- Living fossils include Ginkgo biloba, Limulus, Dinoflagellates etc.

The correct option is B i.e. Ginkgo.

Additional information: Ginkgo biloba also known as maidenhair tree is a gymnosperm plant.
- It is found to be a very old species with some fossils dating back from 270 million years ago.
- It is native to China and has various uses in traditional medicine and can also be used as a source of food.
- The plant has erratic branches and is deep rooted due to which it is resistant to wind and snow damage.
- The plant is dioecious in nature.

Note: The plant has various uses like they are used as a source of food, used as traditional medicine for the treatment of Alzheimer’s disease, used as a dietary supplement.
Besides all these uses, it is having some adverse effects like the overconsumption of its seeds leads to the depletion of vitamin $B_6$, it is having ginkgolic acids that are highly allergic.