Evolution by natural selection essay

Hire Writer Continental drift mainly effects plant species and animal species that live in a wide range; the drifting of the continents broke up and separated species in such a way it was no longer possible for them to come in contact with one another. The non-contact relationship members of that species share with each other would eventually result in genetic isolation in which it would no longer be possible for those species to exchange genes and reproduce with each other. Therefore those now separate species would change themselves for natural selection so they can fit and adapt to their new environments. Pangea to Gondwana and Laurasia Up until roughly — million years ago, the world was only one large supercontinent known to scientists and geologists and Pangea.

Evolution by natural selection essay

Facts Society and Behaviour What is evolution? In biology, evolution is the change in the characteristics of a species over several generations and relies on the process of natural selection. The theory of evolution is based on the idea that all species are related and gradually change over time.

Evolution relies on there being genetic variation in a population which affects the physical characteristics phenotype of an organism. Some of these characteristics may give the individual an advantage over other individuals which they can then pass on to their offspring.

What is natural selection? Individuals in a species show variation in physical characteristics. This variation is because of differences in their genes. Individuals with characteristics best suited to their environment are more likely to survive, finding food, avoiding predators and resisting disease.

These individuals are more likely to reproduce and pass their genes on to their children. Individuals that are poorly adapted to their environment are less likely to survive and reproduce.

Evolution by natural selection essay

Therefore their genes are less likely to be passed on to the next generation. As a consequence those individuals most suited to their environment survive and, given enough time, the species will gradually evolve.

Natural selection in action: This colouring enabled them to hide from potential predators on trees with pale-coloured bark, such as birch trees. The rarer dark-coloured peppered moths were easily seen against the pale bark of trees and therefore more easily seen by predators.

A pale peppered moth on an oak tree. Shutterstock As the Industrial Revolution reached its peak, the air in industrial areas became full of soot.


This stained trees and buildings black. As a result, the lighter moths became much easier to spot than the darker ones, making them vulnerable to being eaten by birds.

The darker moths were now camouflaged against the soot-stained trees and therefore less likely to be eaten. Over time this change in the environment led to the darker moths becoming more common and the pale moths rarer.

A pale peppered moth on a dark tree. Shutterstock What have genes got to do with it? The mechanisms of evolution operate at the genomic level. Changes in DNA sequences affect the composition and expression of our genes, the basic units of inheritance.

To understand how different species have evolved we have to look at the DNA sequences in their genomes. Our evolutionary history is written into our genome. The human genome looks the way it does because of all the genetic changes that affected our ancestors. When DNA and genes in different species look very similar, this is usually taken as evidence of them sharing ancestors.

For example, humans and the fruit fly, Drosophila melanogaster, share much of their DNA. DNA accumulates changes over time. Some of these changes can be beneficial, and provide a selective advantage for an organism.

Other changes may be harmful if they affect an important, everyday function. As a result some genes do not change much. They are said to be conserved. Different types of evolution Convergent evolution When the same adaptations evolve independently, under similar selection pressures. For example, flying insects, birds and bats have all evolved the ability to fly, but independently of each other.

Co-evolution When two species or groups of species have evolved alongside each other where one adapts to changes in the other. For example, flowering plants and pollinating insects such as bees.

Adaptive radiation When a species splits into a number of new forms when a change in the environment makes new resources available or creates new environmental challenges. For example, finches on the Galapagos Islands have developed different shaped beaks to take advantage of the different kinds of food available on different islands.

Sketches of the heads of finches from the Galapagos Islands showing the differences in their beak shapes due to evolution.1. Evolution The theory of evolution has been the subject of debate for many years.

Along other mechanisms of evolution such as genetic drift, mutation and migration, natural selection is a fundamental process that is a direct outcome of the . May 16,  · Evolution Essay Evolution is the theory that all living forms came from ancient ancestors. Through a series of mutations, genetic drift, migration, and natural selection today’s descendants show an amazing amount of similarities and diversity. Natural selection Natural selection is one of the basic mechanisms of evolution, along with mutation, migration, and genetic drift. Darwin's grand idea of evolution by natural selection is relatively simple but often misunderstood.

Since this is a subjective belief, it is likely that this debate will be go on till. Natural selection is the process by which certain characteristics, as dictated by genetic structure, offer a greater chance of survival and therefore reproduction.

Hot Essays: Essay on Darwin's Theory of Evolution

Organisms lacking these. Charles Darwin Essay The famous British naturalist Charles Darwin traveled around the world, wrote several books, and developed the theory of natural selection and evolution.

Charles Robert Darwin was born on February 12, , in Shrewsbury, Shropshire, in the west of England.

Expert Answers Evidence for evolution comes from many different areas of biology:
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Students in introductory biology courses frequently have misconceptions regarding natural selection. In this paper, we describe six activities that biology instructors can use to teach undergraduate students in introductory biology courses how natural selection causes evolution.

What are Darwin’s four postulates of natural selection? List the evidence of evolution that we currently have that supports the theory of evolution by natural selection. What evidence did Darwin use to argue that species are dynamic (and not static)?

May 16,  · Evolution Essay Evolution is the theory that all living forms came from ancient ancestors. Through a series of mutations, genetic drift, migration, and natural selection today’s descendants show an amazing amount of similarities and diversity.

Brief Essay on the Darwin’s Theory of Natural Selection