Charles Darwin proposed the theory of evolution. The theory of evolution states that living things have adapted and changed over time. This theory suggests that all living things developed from earlier types. All living organisms have changed from as they were millions of years ago. This is due to changes and adaptations. Organisms adapt to changing environments. This theory grew from studying living organisms and fossils. Fossils provide us with an insight into the types of animals and plants that existed many years ago.
Adaptations are special characteristics that help plants and animals to survive in a specific environment. If there are any changes in the environment then it is important for the plants and animals to adapt to these changes. This is because it will improve their chances of surviving and reproducing. Generally organisms are well adapted to biotic and abiotic conditions of the environment.
Adaptations are usually inherited from parents or they come from random mutations. There are three types of adaptations:
- Behavioural adaptations
- Physiological adaptations
- Structural adaptations
Is the theory of evolution true or false?
It is important to note that this is just a theory which means it is not a fact or a scientific law. Many scientists accept the theory of evolution; however, many reject it.
Fossils are remains of plants and animals that are imprinted in rocks. Scientists are able to identify changes that have occurred to plants and animals over time.
Palaeontologists are the people who study fossils. As they study fossils from thousands of years ago, they are able to piece together the similarities and differences between organisms. This allows them to understand how the process of evolution occurred.
A common misconception is that humans evolved from apes, although this is not the case. Even though humans and apes share some common characteristics, humans didn’t evolve from apes; however, some believe we share common ancestors that lived millions of years ago. It is also true that organisms are still evolving. Some changes take thousands of years, some take millions of years, and some take less time.
The fossil record is the record in which palaeontologists document the placement of animals and plant fossils.
Many of the fossils found were marine animals because they lived in the sea. The sand and mud below the sea buried their remains quickly after they died.
Many dinosaur fossils have been which provide evidence that dinosaurs existed a long time ago.
How are fossils formed?
Fossilisation is the process by which a fossil is formed, this process requires specific conditions. Fossils are mostly found in sedimentary rocks.
Fossils require specific conditions in order for them to form. When an animal dies the dead remains sink to the ground and slowly get covered in mud and sand. The soft parts of its body decompose leaving the hard parts such as the skeleton. Over time more layers of sediment form on top and the sediment around the skeleton starts to compact and turn into rock. The bones then begin to dissolve in water. The minerals in the water replace the bone which leaves a print of the animal on the rock.
Fossils provide us with evidence of extinct animals such as dinosaurs and mammoths.
There are different ways of describing fossil preservation:
- Moulds and casts
- Preserved remains
Compression is the process in which a dark imprint of the is fossil preserved in sedimentary rock that has undergone physical compression due to high-pressure forces.
Petrification is the process in which organic matter is exposed to minerals. Over long periods of time, it is turned into a stony substance.
Moulds are produced where the original bone or shell is dissolved, leaving a space in the shape of the original material. Over time sediment can fill the space to form a cast.
Preserved remains are rare as it is the preservation of the original soft body or skeleton of organisms.