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I understand evolution as survival of the fittest rule , where its the nature and surroundings that shapes the life by extinction of species which are not fit to survive the nature at that period.

To me its analogy would be like soil passing though a net,where nature act as the net and the soil particles act as lifeforms. The particles whose shape and size are small (fit) will go through the net and live on while the bigger ones (unfit) will get stuck and hence go extinct.

Pretty clear so far.

However there are certain things that do not seem to make sense with this theory for me personally.

  1. When we evolved from primates to humans why did we lose our body mass, muscles and hair? I mean sure we could be intelligent with the muscles and the furcoat would keep us warm and hence more likely to survive.

The explanation I get for this is that we did not had any use of body hair and strong muscles over our intellect so we lost them, however how can WE make it happen ? Its not like intellect requires less muscles or something so how did we lose it from redundancy? whats the mechanism?

2.How does Genetical heritage evolve?

In a nutshell what I want to ask is does our actions (as a species) define our DNA in evolution? Apart from natural mutation and survival of the fittest is there anything that affects the biological evolution? It is believed that child of intelligent parent is supposed to be somewhat intelligent as well, is this linked to heritage or just the environment he grows in?

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  • $\begingroup$ Pt. 2 of your question concerns the famous nature v. nurture debate; feel free to Google that, it's quite interesting. You said: "we did not have any use of body hair and strong muscles over our intellect so we lost them". That is wrong. Natural selection doesn't compare different traits within an individual and choose the ones among them that are the most "superior" (it doesn't "filter" body hair and muscles because we possess intelligence, unless intelligence somehow makes the former traits obsolete or if the traits are an unnecessary burden). Also, I suggest a title change for clarity $\endgroup$ – AleksandrH Jan 22 '16 at 0:28
  • $\begingroup$ To answer the last question, in my opinion, genetically passed intelligence is just a potenial. However, the enviroment he grows matters also. To be more clear, intelligence just express itself based on the "data" (static knowledge) in your brain. Less data means less intelligence expression. How google translate work ? It is artificially intelligent. However, its intelligence alone does not work well. Gtranslate continiously read more and more ebooks with the translations. So it can be more accurate. Same intelligence, but different intelligence expression :) $\endgroup$ – TeoFriendly Jan 22 '16 at 0:33
  • $\begingroup$ Also, in addition to my previous post, I wanted to mention that species which are at a disadvantage don't necessarily go extinct, unless they are repeatedly at a disadvantage over long periods of time and therefore the allele frequencies dwindle to very small percentages, or because an environmental disturbance occurs to which they cannot adapt or recover from. $\endgroup$ – AleksandrH Jan 22 '16 at 0:33
  • $\begingroup$ @ AleksandrH Thats not my question. "we did not have any use of body hair and strong muscles over our intellect so we lost them" is what most people usually tell me. "Natural selection doesn't compare different traits within an individual and choose the ones among them" is what I know as well, but what causes redundant features to be eliminated? $\endgroup$ – user1062760 Jan 22 '16 at 1:21
  • $\begingroup$ This is one of numerous other moments when I would love to downvote a few comments. $\endgroup$ – Remi.b Jan 22 '16 at 2:45
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Welcome to Biology.SE

Issues with the question

  • It is impossible to correctly answer this question as the phrasing is so fantastically unclear, wrong and misleading (no offense, really). I will give a few points here that may help you but the only thing you can really do to answer your own question is take some time to follow an introductory course to evolutionary biology such as Understanding Evolution by UC berkeley (online and free) for example.

  • You probably want to work on the format of the question as numbering lines that have different number of tags looks pretty bad.

  • You are asking 9 different questions (there are 9 question marks at least) that are all relatively unrelated! A post should always be reduced to one single clearly defined question.

A few simple definitions

  • Population: A group of individuals.

  • Locus: A position in the genome.

  • Gene: A functional unit at a given locus that codes for a protein.

  • Allele: A variant of two or more variants at a given locus. Simplified example: At the locus where stands the gene coding eye colour, there are 2 variants brown eyes and blue eyes.

  • Evolution: Refers to any change in allele frequency in a population through time.

  • Phenotype: The manifestation of a gene on the world. In short: It is how someone looks like.

Does evolution thinks?

It is always quite difficult to define what "thinking" means. But really here, we won't need to debate the detail of the terminology of what is a thought. Evolution is a process, it is not an organism, it has no brain and can not think. The answer is "no".

I understand evolution as survival of the fittest rule , where its the nature and surroundings that shapes the life by extinction of species which are not fit to survive the nature at that period.

This is wrong! "survival of the fittest" is just a quick and dirty expression for referring to the process called natural selection. Natural selection describes the fact that alleles conferring higher fitness (that is having lower chance of survival and/or higher fecundity) to individuals carrying the allele, raise in frequency in the population.

Natural selection does not necessarily decrease nor necessarily increase the probability of a population to go extinct.

Apart from natural mutation and survival of the fittest is there anything that affects the biological evolution?

Natural selection and "survival of the fittest" refers to the same process.

Yes, there are other forces that affect evolution (and are absolutely essential) such as mutations and genetic drift.

I want to ask is does our actions (as a species) define our DNA in evolution?

It is unclear what you mean by "define evolution" and you probably want to replace "species" by "population". Yes, the current state of population (including the behaviour of its constituent individuals) affect future evolution of the species.

It is believed that child of intelligent parent is supposed to be somewhat intelligent as well, is this linked to heritage or just the environment he grows in?

This is an interesting question. I wrote an introduction into the concept of heritability (incl. the role of genes and environment in shaping phenotypes) in this post.

When we evolved from primates to humans why did we lose [body mass and muscles]?

You will have to ask this question on a separate post. In this post, you will have to make sure that we indeed lost in body mass. Note that human shape is nicely adapted for high endurance (hunting large mammals over long distance and period of time)

When we evolved from primates to humans why did we lose [..] hair?

This question is a duplicate of this very interesting post. Have a look!

Recommendation

To the risk of repeating myself, I'd recommend that you have a look at a very introductory source of information on evolutionary biology such as Understanding Evolution by UC berkeley (online and free) for example.

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