Living Fossil: Types & Examples

Living fossils are remnants of organisms whose close relatives are becoming extinct. From time to time, we keep hearing the news of extinct species or living species that have died or are on the verge of extinction. 

• Living fossils are considerably old with respect to the origin of the extant clade.
• The connection between extinct plants, animals, and their discovery is the fossil.
• They are considered species of poor lineages.
• Life on Earth is deciphered through the examination of fossils.
• Fossils refer to remains of plants and animals that have been preserved in the Earth’s crust. 
• They are members of a taxon that remained recognisable over a long period of time.
• Living fossil tends to exhibit morphological divergence.
• Snail shell is common example of these types of fossil

Key Terms: Living Fossil, Fossil, Minerals, Rocks, Soil, Sedimentary Rocks, Extinction, Bones, Skull, Teeth, Organism, Species, Bacteria, Fungi, Resin Fossils, Body Fossils

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What is a Living Fossil?

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The living fossil is an organism that has remained relatively unchanged over millions of years or one that has no, or very few, close surviving relatives. The term was coined by English naturalist Charles Darwin in 1859.

• Living fossils represent a species or group that remained so little changed that they provide an insight into now-extinct forms of life. 
• According to Charles Darwin's theory, these animals are still evolving.
• Every living thing on the earth has evolved according to changing environments and rising and falling temperatures.
• These species have adapted to their environmental controls, reaching a peak of competence in environments.
• Living fossils are constantly strengthened by certain physical characteristics.
• Some fossils have no identical features, indicating that the creature once existed.
• These extinct creatures serve as a reminder to the world that other living species are becoming extinct.

Living fossils​ 

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Examples of Living Fossils

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Some important examples of living fossils are as follows:

Unicellular/ Single-Celled Organisms

Unicellular/ Single-celled Organisms have been the most abundant life forms on earth since the beginning of time. Most single-celled life is soft and decays quickly, so unicellular organism fossils are rare.

• However, some forms of single-celled life-secreted shells are called "tests" that can be fossilized.

Multi-cellular Organisms

Multi-cellular Organisms are made up of more than one cell, with groups of cells differentiating to take on specialized functions. The arthropods and jellyfish were thought to be younger than fossil rocks, but there is no evidence that the rock organisms evolved into arthropods or jellyfish. 

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What is a Fossil?

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A fossil is naturally preserved remains or traces of animals or plants that lived in the geologic past. Fossil word comes from the Latin word 'fossus', which means "having been dug up."

• It can be an emblem of a leaf, a petrified log, or the skull of an animal. 
• They are found buried deep within sedimentary rock layers, symbolizing millions of years of soil deposition. 
• The study of fossils is called Palaeontology.
• The fossils have to go through a process of permineralization.
• In this, small rock minerals seeping into the porous space of logs or bones avoid scavenging and make it a fossilized specimen.

Fossil

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Types of Fossils

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Fossils can be categorized in two ways:

By Body parts

These are the remains of once-living organisms which include nails, bones, skull, teeth, etc.

By Traces

These types of fossils also called ichnofossils, are evidence that organisms were present from footprints, tracks, trails, and burrows. They are used to observe the same species that are living and have adapted to the evolution of the earth.

There are six different types of fossils.

Direct Fossils

Any remaining part of an ancient organism is considered a direct fossil. The preserved or altered hard parts of organisms, such as bones or shells, are examples of direct evidence.

• Soft tissues that have been preserved, such as skin or feathers, are another type of direct evidence.

Ichno-Fossils

Ichnofossils are fossils formed from parts that do not belong to living organisms, such as nests, footprints, or faeces.

Chemo-Fossils

Chemo-fossils are fossils that are made up of chemicals left behind by earlier life forms. They are biological signals that allow organisms to communicate with one another.

Resin Fossils

Organisms that have been trapped in amber and have been completely preserved for millions of years. They take the form of bacteria and fungi and, occasionally, insects.

Living Fossils

A living fossil is an organism that has remained in the same form for millions of years, has few or no living relatives, and is the sole surviving lineage from a long-gone epoch.

Living Fossil

Body Fossils

Remains of actual organisms are known as body fossils. The hard skeleton, like shells, teeth, and bones, is preserved, and soft tissue, like skin, muscle, organs, etc, rots away after death. 

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Plants

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Plant fossils are rare in comparison to animal fossils and include compressions, impressions, petrified woods, casts, and moulds. The soft tissues of leaves are typically destroyed long before fossilization occurs.

• Petrified wood is formed when the tissue of ancient trees is completely replaced by minerals.
• It results in the transformation of trunks and branches into stone.
• Imprints of leaves and seed cones are preserved in some sedimentary strata.
• The details of sedimentary strata can be seen with modern microscopes.
• Fossil moulds and casts are formed when plant tissues become encased in hardened sediment and decay.
• The oldest plant fossil is a rare pine species that dates back 90 million years- Wollemi Pines.
• These have existed even during the Jurassic period.
• Once extinct, less than 200 trees are left and protected in Wollemi National Park.

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Things to Remember

• A living fossil is an organism that has remained in the same form for millions of years.
• It has few or no living relatives and is the sole surviving lineage from a long-gone epoch.
• Fossils are remains or traces of animals or plants that were naturally preserved and lived in a distant geologic past.
• The study of fossils is called Palaeontology.
• Animals keep evolving according to changing environments, atmospheric composition and conditions on the earth. 
• Yeast, Amoeba, Algae, Protozoa, and Bacteria are some of the examples of unicellular organisms.