How did organisms transition from single cells to multi-celled forms?

[matthyaouw]

The development and evolution of organisms always seemed reasonably easy to grasp for me, but there is one thing that always threw me off. I can see how single celled organisms can evolve & change, & how multi-celled organisms do so, but how was the leap made from singular cells to a form like ours where each cell is so dependent on the others that it would stand no chance if cut off? Any theories or ideas?

 

[Monique]

You might want to look into the biology of sponges: they seem to be the present-day bridge between single/multicellular life.

 

[iansmith]

You might also want to look at volvox. These protozoan are one of the first example of asexual colony with specialized cells.

http://www.microscopyu.com/moviegallery/pondscum/protozoa/volvox/index.html
http://www.microscopy-uk.org.uk/mag...microscopy-uk.org.uk/mag/art97b/volvoxms.html
http://www.microscopy-uk.org.uk/mag...microscopy-uk.org.uk/mag/artdec03/volvox.html

 

[matthyaouw]

Thanks peoples. I'll go do some researching.
Not been taught a thing about these in college. Its typical curriculum isn't it- they'll teach me all about my nervous system, but nothing about why I have enough cells to need one.

 

[Moonbear]

Thanks peoples. I'll go do some researching.
Not been taught a thing about these in college. Its typical curriculum isn't it- they'll teach me all about my nervous system, but nothing about why I have enough cells to need one.

Hmmm, actually, that's not a typical curriculum. Usually colonial organisms are covered prior to mammals and mammalian organ systems. Did you take a biology course for biology majors, or for non-biology majors? Maybe things were skipped over if you aren't a bio major (often the difference is trying to squeeze in a reasonable amount of material in a one semester course for non-majors vs a 2 semester course for majors).

 

[matthyaouw]

I'm from England actually, so I'll bet our curriculums are somewhat different. College is somewhat different, and way less specialised than in the U.S.A. (I assume that's where you're from). It's like an intermediate stage between high school & university in which you can do up to 5 "A level" courses on more or less whatever you like, so there is no where near the amount of detail in each course that you would find in the U.S.
The real tricky stuff begins in university, but sadly, i chose physical geography rather than biology, so I guess I'll never know a huge amount about it.

 

[nautica]

I'm from England actually, so I'll bet our curriculums are somewhat different. College is somewhat different, and way less specialised than in the U.S.A. (I assume that's where you're from). It's like an intermediate stage between high school & university in which you can do up to 5 "A level" courses on more or less whatever you like, so there is no where near the amount of detail in each course that you would find in the U.S.
The real tricky stuff begins in university, but sadly, i chose physical geography rather than biology, so I guess I'll never know a huge amount about it.

I would hope that you will not limit your knowlegde to what you learn in college. Books can be read and studies completed with or without college.

Nautica

 

[matthyaouw]

I know. I'd love to learn more too- for now it's just a question of what time & resources I have avaliable. Uni can be fairly time consuming, and if I'm focussing too much effort into biology, I daresay I would get a fairly poor grade at the end of my course I'm sad to say. The university offer a few extra modules in other subjects that you can do instead of one from your chosen course- I'm hoping to do a biology module at some point if any catch my interest. Plus my Biogeography and Geobiology modules have some overlap with biology too.