Evolution of flight?

Question

I just thought of this today. In vertebrates, three groups have developed flight, reptiles, birds (I know, I know they're sort of reptiles), and mammals (bats). So why did only one group of arthropods (insects) develop flight? Any one have any info that I'm unaware of, or any theories?

Answer 1

This is one of those interesting evolutionary questions where I don't think we'll ever have a definite answer on; all we can do is logically speculate.

First of all, only birds, bats, and insects have true flight. Let's exclude gliding from any analysis. First it's important to recognize the extreme diversity of insect flyers that exist; flying is often suggested as one of the major characteristics that led to the success of insects. I believe it is this success that has precluded the evolution of any other invertebrates developing flight. When discussing ecological niches, the adaptive radiation of flying insects excludes the development of other taxa from developing flight. The only invertebrate that I can forsee of possibly also developing flight are arachnids (once again a testament to arthropods, the exoskeleton has allowed it to radiate terrestrially; it would be a terrestrial taxa, and I can't see worms or anything without a skeleton of some sort developing flight). But any sort of development of flight by them would just be moving in to a niche of flying insects, and thus, that's why I don't think it has ever occured.

Still, it is interesting that evolution seems to have evolved twice within amniotes, but only once among invertebrates.

Answer 2

First is the usefulness of flight. Spiders don't need wings because they can use their silk to fly. Some send out a single web to catch the wind others build sacs that they use to migrate.
Second is the question why the Chordata have so many "fliers" while Of the 13 other phylum only the insects are active fliers.

I would conclude the animals that live in the sea, do not need the air to go where they want for food or other purposes. Of the land animals evolution is derived from advantage That is one characteristic confers an advantage over his nearly identical kin, that creates a trait that will be passed on. But a trait can not be developed just because it is better. It needs a change in DNA which is arbitrary in occurrence. One that occurs and is an advantage is retained. But you can not get that change just because it would be good. Otherwise we would all save on the hassle at the airport by conferring flight on our offspring.

Answer 3

I believe your question is flawed based on subdivision. Flight is quite common amongst Cordates and Anthropods even though some members under those categories have not attained it. Look at the diversity of Arthropoda -vs- Cordata. I would tend to say there is more commonality amongst members of Cordata then of Anthropoda considering to be a bug you only need an exoskeleton and not a whole complex spine. Anyway, I tend to think that flight is quite a relative term based upon the medium. I would consider controlled movement in water a form of flight, even though I posses a terrestrial bias and know what you mean. Given the origins of life in water, It is reasonable to say the only reason we have a limited population of gaseous fliers is time. Billions of years in the water and only millions out, that is 40:1 in favor of aquatic diversity over terrestrial and something like 90:1 for the fliers! I'd say the fliers are doing OK. Give it some time to get that ratio down to 10:1 and I bet the skies will be teeming! (That is still another 500 million years or so.)

I believe the Classification system is flawed, so to call a bat, bird, & lizard different and a spider, millipede, & butterfly the same is inaccurate, but I do believe I have given you a more evolutionary concept with the ratios of time.

I must disagree with Paul, there is a corrective process in the cell which allows t-RNA to retain or amplify a gene in division. This was finally proven when genes physically removed from the DNA reappeared a generation later. As it turns out, We can, by our behavior, influence the genes of our offspring. This and not random happenstance can account for Evolution.