Jump to content
SimonFunnell

Evolution has no direction?

Recommended Posts

Imagine if our atmosphere were significantly more dense.. flying elephants! :eyebrow:

No thanks - can you imagine having to wash your car after that?

Share this post


Link to post
Share on other sites

Bats evolved more of a nocturnal lifestyle to keep out of the way of birds who are much more efficient flyers than the primordial bats were.

 

Citation? I'm trying to imagine a scenario in which bats are being knocked out of the air in such great numbers by clumsy birds that it had a significant evolutionary impact.

Share this post


Link to post
Share on other sites

Citation? I'm trying to imagine a scenario in which bats are being knocked out of the air in such great numbers by clumsy birds that it had a significant evolutionary impact.

 

I interpreted that as keeping out of the way of predatory birds, rather than literally having to keep out of the way of flying birds.

Share this post


Link to post
Share on other sites

This is the real story why bats fly at night:

 

 

The Bat, the Birds, and the Beasts A GREAT conflict was about to come off between the Birds and the Beasts. When the two armies were collected together the Bat hesitated which to join. The Birds that passed his perch said: “Come with us”; but he said: “I am a Beast.” Later on, some Beasts who were passing underneath him looked up and said: “Come with us”; but he said: “I am a Bird.” Luckily at the last moment peace was made, and no battle took place, so the Bat came to the Birds and wished to join in the rejoicings, but they all turned against him and he had to fly away. He then went to the Beasts, but soon had to beat a retreat, or else they would have torn him to pieces. “Ah,” said the Bat, “I see now,

“HE THAT IS NEITHER ONE THING NOR THE OTHER HAS NO FRIENDS.”

 

http://www.bartleby.com/17/1/24.html

;)

Share this post


Link to post
Share on other sites

Citation? I'm trying to imagine a scenario in which bats are being knocked out of the air in such great numbers by clumsy birds that it had a significant evolutionary impact.

I saw a documentary on bats and predatory birds knew when the bats were leaving their caves and had a feast. There would definitely be an evolutionary impact from predation, for the ones capable of finding food at night would have an advantage.

Bats are rare in NZ so I don't have any personal observations on their behaviour. Sorry my knowledge was based on the documentary.

They keep out of the way so they don't get preyed upon not just to avoid in flight collisions.

Edited by Robittybob1

Share this post


Link to post
Share on other sites

I saw a documentary on bats and predatory birds knew when the bats were leaving their caves and had a feast. There would definitely be an evolutionary impact from predation, for the ones capable of finding food at night would have an advantage.

Bats are rare in NZ so I don't have any personal observations on their behaviour. Sorry my knowledge was based on the documentary.

They keep out of the way so they don't get preyed upon not inflight collisions.

Perhaps, they found an untapped resource niche in the form of airborne night insects... competition is minimal for them.

Edited by StringJunky

Share this post


Link to post
Share on other sites

Perhaps they found an untapped resource niche in the form of airborne night insects... competition is minimal for them.

Both the bats and the night flying insects would benefit from the absence of birds at night. But there was the problem of locating the insects in the dark. That as we know was via echolocation but that isn't just a learned skill but one genetically engineered into their DNA I presume. They would need a larynx capable of making the high frequency clicks and large ears to pick up the source of the echo and the brain to make the mental map from the echos, the wings to change direction in flight etc etc ...

I have tried echolocation myself and you can pick up large objects nearby. That is a learned skill. I am watching a documentary on evolution of flight "Evolution of Flight and Echolocation in Bats" (I'm not finished yet)

Edited by Robittybob1

Share this post


Link to post
Share on other sites

Both the bats and the night flying insects would benefit from the absence of birds at night. But there was the problem of locating the insects in the dark. That as we know was via echolocation but that isn't just a learned skill but one genetically engineered into their DNA I presume.

I have tried echolocation myself and you can pick up large objects nearby. That is a learned skill. I am watching a documentary on evolution of flight "Evolution of Flight and Echolocation in Bats" (I'm not finished yet)

In the beginning they probably started out in forests leaping from tree to tree at dusk/night and then evolved to glide, then onto flying. Poor eyesight and echolation possibly co-evolved with the flight?

Share this post


Link to post
Share on other sites

In the beginning they probably started out in forests leaping from tree to tree at dusk/night and then evolved to glide, then onto flying. Poor eyesight and echolation possibly co-evolved with the flight?

There aren't many fossils to tell how the process went. Nothing wrong with that scenario. When I'm finished maybe I'll summarise what the YT was about.

Share this post


Link to post
Share on other sites

The YT is really educational and shows the effort a good scientist goes through into attempts to prove the fossil is a missing link in the evolution of bats.

Share this post


Link to post
Share on other sites

There is the fact that evolution itself means that there is no perfection. One can always change for the better. So although evolution drives toward perfection, or more exactly the ability to survive and reproduce to keep the species alive, there is always room for perfection.

This is because there is always the fact that evolution itself is not perfect either. it has to depend on chance. As in that the only reason wings exist is coz of chance mutations and then the factor of survival of the fittest took over, making birds with better wings better able to survive. SO One cannot say with a hundred percent confidence that humans will evolve longer fingers or lose body hair or grow wings, since the probability of those mutations occurring are not a 100%. in other words there is always a chance that we might have a mutation for wings, but there is also a chance that our genes will never mutate to give us wings.

 

 

Thus Evolution doesn't have a predetermined direction, because there was a chance that the mutation for wings never would have happened, thus preventing the species of birds to exist. There was a chance that the mutation for higher level thinking would never have occurred. So evolution is not a predetermined path, instead it is almost like a traveler with no destination, just randomly choosing his own path, totally random. He turns left sometimes, sometimes he turns right, sometimes he goes forward, sometimes he even goes backward.

 

P.S. Do not confuse yourself over the "survival of the fittest" or "natural selection". Those "forces" are not random. The organisms with the best genes do survive and thus make the species evolve. All i am saying is that for those differences to occur-the same differences that allow for natural selection-exist because of mutations in the genes. Once these mutations occur by CHANCE, the organism with the new mutations and new physical or mental abilities has to compete with the organisms who do not have the same abilities as he does. If his abilities allow him to better survive and reproduce then his differences are passed down, and if those same difference significantly allow his offspring to survive better then they may appear in more of the species in later generations.

Share this post


Link to post
Share on other sites

but that isn't just a learned skill but one genetically engineered into their DNA I presume.

I do hope this was an attempt at an April 1st joke...

Share this post


Link to post
Share on other sites

I do hope this was an attempt at an April 1st joke...

Said on the 4th of March ... what was that about now?

 

That as we know was via echolocation but that isn't just a learned skill but one genetically engineered into their DNA I presume.

Is echolocation a learned skill in bats? Do the parents show their young bats how to do it?

Edited by Robittybob1

Share this post


Link to post
Share on other sites

You were seemingly suggesting that echolocation was genetically engineered into Bats' DNA.

 

What exactly did you mean by "engineered"?

Edited by Daecon

Share this post


Link to post
Share on other sites

You were seemingly suggesting that echolocation was genetically engineered into Bats' DNA.

An instinctive behaviour? What do you think? Are instincts genetic? It has been something I have been trying to understand.

Share this post


Link to post
Share on other sites

I would imagine it's an evolved characteristic.

 

Using a phrase like "genetically engineered" would seem to imply that you believe this characteristic was deliberately manufactured and introduced by an outside, intelligent agency.

Edited by Daecon

Share this post


Link to post
Share on other sites

I would imagine it's an evolved characteristic.

 

Using a phrase like "genetically engineered" would seem to imply that you believe this characteristic was deliberately manufactured and introduced by an outside, intelligent agency.

Could you identify which part of the DNA could code for "an evolved characteristic". That is what I mean by "engineered". Is it in the genetic material? Is it coded memory?

Share this post


Link to post
Share on other sites

Could you identify which part of the DNA could code for "an evolved characteristic".

Um... pretty much all of it? That's kinda what DNA does.

Share this post


Link to post
Share on other sites

The answer here is to not over think the topic. Evolution is not random but "random" mutations drive it. If you want to get philosophical about it you have to deal with determinism and that really just muddies the water. I would recommend that everyone take a look at what Daniel Dennett has to say on free will to clarify their thinking.

Share this post


Link to post
Share on other sites

So we have a machine that automatically generates random wing designs and tests them (something like evolutionary theory).

 

Some designs win out, others lose.

 

But the winning design was predetermined by the environment it was being tested in.

 

We could have an environment that does not support flying and hence no wing designs will work.

 

Consequently, the design of the wing is an inherent part of the environment.

 

In this way, the random generation of forms is irrelevant, the outcome is always the same, the wing that best suits the environment, wins out.

 

Its not just with wings, abstract forms are part of the universe (the system) and life inherits its form from it, it is formed by the environment.

Share this post


Link to post
Share on other sites

So we have a machine that automatically generates random wing designs and tests them (something like evolutionary theory).

 

Some designs win out, others lose.

 

But the winning design was predetermined by the environment it was being tested in.

 

Not necessarily. If you ran the experiment multiple times (lets assume it is a simulation, or perhaps the use of genetic algorithms in airraft design) you might not get the same result. You may end up with different wings, some better than others but all meeting the minimum requirements.

 

But often the solutions end up very similar (because there are only so many ways of solving the problem).

 

We see this in the real world. Many functions and organs have evolved multiple times and can be different. For example, eyes have evolved many times and there are many different versions such as the compound eyes of flies to single eyeball in mammals. On the other human and octopus eyes developed completely independently but are quite similar (but with some fundamental differences).

https://en.wikipedia.org/wiki/Convergent_evolution

 

 

In this way, the random generation of forms is irrelevant, the outcome is always the same, the wing that best suits the environment, wins out.

 

That is almost true. But the random part is not irrelevant because there is no other mechanism to get to the end result.

Share this post


Link to post
Share on other sites

It also neglects that it is rare that one simple factor is the sole evolutionary drive. Various designs may have different advantages and disadvantages. For example, a very energy efficient flight model may be very slow. Thus, it may be possible that for objects with this design predation avoidance may become more important. Another one is faster, but much less energy efficient. Then other factors like improved foraging may be necessary to survive etc. That is one of the reasons organisms explore different niches instead of optimizing everything to one particular aspect of the environment.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.