Why is overproduction important to a species

Inheritance of a character occurs only if that character is passed from one generation to the next during reproduction. In other words, it is reproduction that is the crucial factor in natural selection. In a nutshell, natural selection is about the reproduction - rather than survival - of the fittest.

The term 'fitness' has a very particular meaning in biology. Making the decision to study can be a big step, which is why you'll want a trusted University. Take a look at all Open University courses. If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module , or a module which allows you to count your previous learning towards an Open University qualification.

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All rights reserved. The Open University is authorised and regulated by the Financial Conduct Authority in relation to its secondary activity of credit broking. Skip to main content. Search for free courses, interactives, videos and more! Free learning from The Open University. Featured content. Free courses. All content. Charles Darwin put forth a coherent theory of evolution and amassed a great body of evidence in support of this theory.

In Darwin's time, most scientists fully believed that each organism and each adaptation was the work of the creator. Linneaus established the system of biological classification that we use today, and did so in the spirit of cataloguing God's creations. In other words, all of the similarities and dissimilarities among groups of organisms that are the result of the branching process creating the great tree of life see Figure 1 , were viewed by early 19th century philosophers and scientists as a consequence of omnipotent design.

Figure 1: A phylogenetic "tree of life" constructed by computer analysis of cyochrome c molecules in the organisms shown; there are as many different trees of life as there are methods of analysis for constructing them.

However, by the 19th Century, a number of natural historians were beginning to think of evolutionary change as an explanation for patterns observed in nature. The following ideas were part of the intellectual climate of Darwin's time. This habit sustained for long, has had the result in all members of its race that the forelegs have grown longer than the hind legs and that its neck has become so stretched, that the giraffe, without standing on its hind legs, lifts its head to a height of six meters.

In essence, this says that the necks of Giraffes became long as a result of continually stretching to reach high foliage. Larmarck was incorrect in the hypothesized mechanism, of course, but his example makes clear that naturalists were thinking about the possibility of evolutionary change in the early 's.

Darwin's Theory. Species populations of interbreeding organisms change over time and space. The representatives of species living today differ from those that lived in the recent past, and populations in different geographic regions today differ slightly in form or behavior. These differences extend into the fossil record, which provides ample support for this claim. All organisms share common ancestors with other organisms. Over time, populations may divide into different species, which share a common ancestral population.

Far enough back in time, any pair of organisms shares a common ancestor. For example, humans shared a common ancestor with chimpanzees about eight million years ago, with whales about 60 million years ago, and with kangaroos over million years ago.

Shared ancestry explains the similarities of organisms that are classified together: their similarities reflect the inheritance of traits from a common ancestor. Since then, biologists and paleontologists have documented a broad spectrum of slow to rapid rates of evolutionary change within lineages. T he primary mechanism of change over time is natural selection, elaborated below.

This mechanism causes changes in the properties traits of organisms within lineages from generation to generation. This process is natural selection.

Membrane Structure 4. Membrane Transport 5. Origin of Cells 6. Cell Division 2: Molecular Biology 1. Metabolic Molecules 2. Water 3. Protein 5. Enzymes 6. Cell Respiration 9. Photosynthesis 3: Genetics 1.

Genes 2. Chromosomes 3. Meiosis 4. Natural selection occurs through an interaction between the environment and the variability inherent among the individual organisms making up a population.

The product of natural selection in the adaptation of populations of organisms to their environments. Evolution is not progressive - Evolution is not designed to produce the best quality products, it only seeks to design adaptations 'that will do the job' most efficiently and economically. Therefore, evolution used the 'mammal template' throughout the development of all mammal species - eg.

Evolution is not an argument for the status quo - Evolution does not dictate why things are the way they are. It must be remembered that some of an animals features may be trade-offs or by-products of the evolution of an unrelated adaptation. Evolution provides constraints - What has gone before sets physical limits on what we can do now.

This is seen in the fact that we learn some things much more readily than others.