The Evolution and Extinction of Organisms

Introduction to The Evidence of Evolution and Living Fossils

Evolution is proven by all fossils. The phrase “living fossil” usually refers to the similarities and differences between living things and the fossilized remains of extinct organisms whose structure and behavior were basically unchanged.

Charles Darwin, an English naturalist, coined the phrase “living fossil.” He has written extensively about those living things that have remained basically unchanged for billions of years in one of his most well-known books, “The Origin of Species.” He also listed species that have not evolved since the time of their fossilized ancestors.

Importance of Living Fossils

One of the best ways to show the common ancestry of distinct living species is through living fossils. Older fossils are discovered to be similar to modern organisms if both living creatures and fossil creatures are the same and similar. Darwin thought that every living fossil was unique and strange. Many fossils are simple to recognize because they are the remains of extinct animals.

Every living thing has evolved over time to adapt to its surroundings, to rising and falling temperatures, and to other changes in the components of the atmosphere.

Explanation:

Evolution

Evolution can be defined as a change in species over time. Dinosaur fossils are an important source of information about Earth’s past life and evolution.

Evolution of Life

Evolution has produced the variety of life that exists on Earth today.

Since life first emerged on Earth between 3.5 and 4 billion years ago, it has continued to develop.

Initially, there were just single-celled, primitive species on Earth.

The first multicellular organisms appeared much later, and as a result, the diversity of life on Earth significantly increased.

The evolution of life on Earth is shown in this timeline. In the overall scheme of things, humans are a relatively new addition.

The evolution of life on Earth is currently the most widely accepted theory.

Evidence for evolution

Four main sources have provided the majority of the evidence for evolution

1. The evolution of earlier species is seen in the fossil record.
2. The shared chemical and skeletal structures of related living types.
3. The geographic range of closely related species.
4. The observed genetic alterations in living things over a long period of time.

Fossil Record

Animal and plant remains were discovered in sedimentary rocks. Rock deposits provide an indisputable record of historical changes over very long time periods. This proof demonstrates the enormous variety of living things that have existed.

Some ancient creatures possessed characteristics that crossed over into important groupings of organisms. Their presence demonstrates that species are not stable and can change through time to become new species.

Evolutionary Gaps Filled in the Fossil Record

The evidence also demonstrates that gaps in the fossil record that initially appeared to exist are actually the result of incomplete data collecting. These so-called “gaps” or “missing links in the chain of evolution” are increasingly filled by transitional fossil specimens as we learn more about the evolution of certain species lines. One of these gaps was bridged by small, bipedal dinosaurs and birds, which was one of the first.

Archaeopteryx Fossil

A 150–145-million-year-old fossil of Archaeopteryx was discovered in southern Germany just two years after Darwin wrote On the Origin of Species.

It had broad wings and feathers like birds. It also had jaws with teeth and a long bone tail like dinosaurs, as well as the skeletal elements of both. This finding supported the theory that birds descended from reptiles.

Mass Extinction

As defined by scientists, mass extinction is when approximately three-quarters of all species disappear over a short period of geological time, which is less than 2.8 million years.

First Mass Extinction: ~ 440 Million Years Ago (Ordovician-Silurian Extinction)

Corals and shelled brachiopods were abundant during the time of the first mass extinction on Earth, but they had not yet made it onto land.

The southern supercontinent Gondwana had a sudden beginning of mass glaciation near the end of the Ordovician period. Glaciation of this magnitude locked up a large portion of the world’s water and significantly reduced sea levels, which deprived many species of their most essential habitats, destroyed food chains, and reduced reproductive success.

Second Mass Extinction: ~ 365 Million Years Ago (Late Devonian Extinction)

A great number of ancient marine species rose and fell throughout this time. The majority of life was swimming through the waters at this time, even though animals had started to evolve on land. Until vascular plants, including trees and flowers, probably brought about second mass extinction.

Third Mass Extinction: ~ 253 Million Years Ago (Permian -Triassic extinction)

The “Great Dying,” as this extinction event is commonly known, is the biggest to ever affect Earth. It destroyed the land-dwelling reptiles, insects, and amphibians, wiping out around 90% of all species on the earth.

At the end of this time, explosive volcanoes erupted in what is now Siberia. Due to the significant amount of carbon dioxide that was released into the atmosphere, the earth became warmer due to the greenhouse effect. Weather patterns changed, and as a result, sea levels rose, and acid rain pounded the earth.

Fourth Mass Extinction: ~ 201 Million Years Ago (Triassic-Jurassic extinction).

The Triassic phase saw the emergence of new and varied life and the emergence of dinosaurs. Sadly, a lot of volcanoes erupted around that time as well.

Similar to the Permian extinction, climatic change and the loss of Earth’s life were caused by massive carbon dioxide emissions from volcanoes. The ice melted, sea levels rose, and the atmosphere became warmer and more acidic. Many land and marine species perished as a result, including some flying pterosaurs and gigantic prehistoric crocodiles.

Fifth Mass Extinction: ~ 66 Million Years Ago (K-Pg extinction)

All the Non-avian Dinosaurs Were Killed in the Fifth Mass Extinction

The Cretaceous-Paleogene extinction, sometimes called the day the dinosaurs died, is very well-known for all the mass extinction incidents. Geologists refer to the event as the “K-Pg extinction” since the letter “C” stands for a prior geological time known as the Cambrian. The event is also occasionally referred to as the “K-T extinction.” The letter “K” is derived from the word “Kreide,” which is German for “Cretaceous.”