2007-05-30 08:59:32 · 12 answers · asked by Anonymous in Society & Culture ➔ Religion & Spirituality
none of the above, really. In the early fetal stages, there are vein-like tubes, blood-like goo and cells that pulse electrically before any of those things. In simplistic creatures there are vein-like tubes, blood-like goo and cells that pulse electrically
I need an operational definition...thanks!
(When my son was born, there was blood first, btw)
2007-05-30 09:05:34 · answer #1 · answered by LabGrrl 7 · 3⤊ 1⤋
Your cells are surrounded by fluid through which passes many of the nutrients and chemical messengers that the cells require. Most organisms have this fluid, this is teh precursor for blood. As an organism gets bigger, the cells get further and further away from the food and oxygen, so some type of delivery system is needed. Colonial organisms (those that live in colonies but are not a single multi-cellular organism) develop blood-vessel like systems to feed the organisms on the inside and those far away from the food source. As the organism gets bigger, a pump becomes required.
Nutritious fluid first (blood), then vessels and/or a pump (heart) (there are variations on whether a pump or vessels come first).
2007-05-30 09:14:49 · answer #2 · answered by Momofthreeboys 7 · 2⤊ 0⤋
Easy one. There are primitive organisms today with blood but no enclosed circulatory system. There are organisms with a contractile vessel that pumps the blood, but no peripheral vessels. There are organisms with simple vessel systems through which blood is pumped by contractile sections of vessels, or by encircling muscle bands. There are hearts with 1, 2, 3 and 4 chambers. In other words, all the necessary steps in the evolution of a closed circulatory system with a 4-chambered heart are still alive and observable today. Exactly the same is true of the eye, kidney, lungs, brain, or virtually any anatomical structure you can name. Next?
2007-05-30 09:05:23 · answer #3 · answered by PaulCyp 7 · 6⤊ 0⤋
Something like blood, but not blood. IE: A very simple concoction that filled the same role, only less efficiently.
Then would be veins and arteries, though in equally less efficient forms, then a heart, probably even more simple than a fishes.
Seriously, have you studied how different circulatory systems work?
2007-05-30 09:04:26 · answer #4 · answered by Squishy Mckay 2 · 5⤊ 1⤋
The blood, presumably, in much the same way that many insects still are today, without blood vessels or a heart.
There you go! You're on your way to understanding evolution! With a little more study, you'll understand why it's foolish to say something is false, when you know nothing about it! Hooray!
2007-05-30 09:05:45 · answer #5 · answered by Anonymous · 4⤊ 1⤋
Primordial amino acid complex. Lol; I get a kick out of your logic, though. I get images of a disembodied heart lying among some ferns, thumping away!
2007-05-30 09:04:28 · answer #6 · answered by Queenie in the vitamins 3 · 5⤊ 0⤋
Awww, PaulCyp and Labgrrl already shot your lame irreducible complexity question to pieces. dammit!
2007-05-30 09:08:11 · answer #7 · answered by Anonymous · 3⤊ 0⤋
This is, without a doubt, the most unintelligent question I've seen today.
2007-05-30 09:06:58 · answer #8 · answered by cityofoak 2 · 4⤊ 2⤋
blood, simpler organisms like insects have hemolymph, but no real circulatory system
2007-05-30 09:02:44 · answer #9 · answered by Nick F 6 · 4⤊ 1⤋
WOW!!!!!!!!!!!!!!!
i will explain it to you but i believe you would not understand SIMPLE human anatomy
2007-05-30 09:09:42 · answer #10 · answered by Anonymous · 2⤊ 0⤋