- Dec 25, 2003
- 42,070
- 16,820
- Country
- United States
- Gender
- Male
- Faith
- Atheist
- Marital Status
- Private
Upvote
0
Starting today August 7th, 2024, in order to post in the Married Couples, Courting Couples, or Singles forums, you will not be allowed to post if you have your Marital status designated as private. Announcements will be made in the respective forums as well but please note that if yours is currently listed as Private, you will need to submit a ticket in the Support Area to have yours changed.
We only have two species of egg-laying mammals left: the platypus and the echidna.
Congratulations! The more we study, the better. Any subject you study (biology, astronomy, a foreign language, history) is a personal improvement.I have studied
Congratulations again, for your excellent choice! The ToE is a fascinating subject.evolution some
That doesn't matter. All beginning is difficult. With the help of many you will start understanding it.but I really don't understand it.
Now here things go wrong. You admit that you don't understand the ToE, yet you start aking questions about a highly technical aspect. I would suggest to grasp the basics first (and grasp them firmly) and tackle the difficult ones later.This is gonna sound odd, but I don't see how reproduction evolved.
"Everything" might be a little too much, but "yes"The theory of evolution says that everything happened gradually.
[...]
Did you say "gradually" in the previous sentence? Do you consider the jump from "a group of cells" to egg laying animals "gradual"? Consider that for laying eggs an organism needs ovaries, an oviduct etc, that are quite complicated organs. I suggest that you reaaly study the basics of evolution. Really.My problem is that I don't see how groups of a few cells started laying eggs.
I understand that. Especially since fish and birds reproduce sexually too. And since mammals don't descend from birds. Here I would suggest to drop the subject of evolution altogether, and start with basic biology, first. And I mean really basic biology.I also have a hard time understanding how a transition from birds and fish (who lay eggs) into mammals (who have sexual intercourse) could have happened gradually.
I can understand that.I especially have trouble imagining how the male/female division evolved. It doesn't make sense.
I made some suggestions above.Do you have any ideas? Thanks in advance!
Echidnas are a family with 2 extant genera and 6 extant species.
Yes, and most importantly, they should know why. I'm a big fan of understanding my own beliefs.Don't worry, I believe Christians should study evolution. God doesn't tell us how He created the Earth. I also think people should know what they don't believe, in addition to what they do!
I do my bestAnd I would like to learn from you, you are good at explaining.
Some birds do actually do that! Remember that an egg contains pretty much everything (aside from air) that a baby bird needs to develop to hatching. So I don't think eggs would actually get any heavier after they are laid. Many birds stagger their egg laying over several days, but not all do. (Case in point: petrels, which of course fly, but still manage to lay scarily enormous eggs for their size.)Thank you for your post, it was very understandable and informative. The part that is probably hardest for me is imagining an organism going from laying eggs to internally growing their own. for example, I think a bird that suddenly tried to grow all it's eggs inside of it would die pretty quickly, as it might not be able to fly hunt defend itself, etc.
They are not vertebrates, they are the living sister group of vertebratesWhat you may find even more interesting are the tunicates. These are basal urochordates that split off early in vertebrate evolution. They are very simple vertebrates without a hard endoskeleton and many of the features you are familiar with in other vertebrate species. What we find is that these very simple vertebrates are hermaphroditic (i.e. they have both male and female gonads in the same individual).
Tunicate - Wikipedia, the free encyclopedia
They are not vertebrates, they are the living sister group of vertebrates
There were mammals around at the time of the reptiles or dinosaurs. But the moist warm climate favored the dinosaurs. When the climate changed then the mammals became favored and they began to multiply. Amphibians like turtles and alligators were also able to survive the change.How did organisms that laid eggs turn into mammals? Can anyone shed some light on that?
There may not be for much longer. According to Wikipedia, there are only four extant species -- and three of the four are listed as "critically endangered".Oh, my mistake. Glad to see that there are more than I thought.
Sorry, but where does all this nonsense about climate change come from?There were mammals around at the time of the reptiles or dinosaurs. But the moist warm climate favored the dinosaurs. When the climate changed then the mammals became favored and they began to multiply.
Never mind that neither turtles nor alligators are amphibians.Amphibians like turtles and alligators were also able to survive the change.
I have studied evolution some, but I really don't understand it.
This is gonna sound odd, but I don't see how reproduction evolved.
The theory of evolution says that everything happened gradually. My problem is that I don't see how groups of a few cells started laying eggs.
I also have a hard time understanding how a transition from birds and fish (who lay eggs) into mammals (who have sexual intercourse) could have happened gradually.
I especially have trouble imagining how the male/female division evolved. It doesn't make sense. Do you have any ideas? Thanks in advance!
FYI, circumventing the forum's censor is against the rules.(I sh*t you not!)http://www.youtube.com/watch?v=S0c3NyupRuY
What do you mean by sexual separation?Sexual separation may have it's origins in Flatworms.
As a biologist, this makes absolutely no sense to me. What's a crown species? Do you mean crown group? But that still makes no sense. Crown groups are all surviving members of a lineage.Largely considered to be the crown species for many extant genera...
They have nothing to do with chordates. Chordates include vertebrates like ourselves, plus sea squirts and their kin, and these guys. Flatworms are in an entirely different part of the animal tree and possess none of the defining features of chordates.as they are considered to be among the first chordates...
Again, that's an outdated idea (unless you are thinking of acoels, which - well, we're still not sure what they are, but one thing they almost certainly aren't is flatworms). Also, even if they were the furthest possible bilaterians you could find from a human vantage point, that doesn't mean "they" did anything first. That is a common misunderstanding of how phylogenies work. (It is also a giant pet peeve of mine.) The animal that first adopted bilateral symmetry would have been a common ancestor of flatworms and us. (Unless we come from flatworms, which to the best of anyone's knowledge isn't the case)...and among the first to adapt bilateral symmetry.
Frogs can change sex? Which ones?What's interesting is that while they do preform a "mating ritual" (called Penis Fencing (I kid you not!)) there seems to be no division in the sexes. Both partners are both male and female... It may be that it's more beneficial for one to produce the sperm and one to produce the eggs rather than both as more energy would be required to preform both functions which would explain why there's a division in the sexes as there is today in most terrestrial species although many can still change sex at any time (something seen most commonly in amphibians, mainly frogs).
Since plants have gender as well, the advent of sex started a very, very long time ago.
So you aren't really interested in learning.
You need to realize that the reason we know anything at all is because there are those who are passionate about science and have devoted their careers to studying the very questions you ask, so that you might learn and understand the processes. And to claim that it takes more faith to believe something, because you don't understand it, is the argument from ignorance. Might it be more wise to claim that this information is difficult to understand, but that you'll devote the amount of time it takes to really understand the details? If you're being honest here, you would have to admit that your understanding of science is skewed by your religious dogma, and that there would be no amount of facts and evidence to sway you.
These links may shed some light on this topic. It's by no means simple or easy to understand!
As in separation between male and female... didn't know how else to say it.What do you mean by sexual separation?
Yeah wrong term, I know. I understand that while Flatworms are primitive, they've evolved just as much as everything else and are far removed from their ancestors.As a biologist, this makes absolutely no sense to me. What's a crown species? Do you mean crown group? But that still makes no sense. Crown groups are all surviving members of a lineage.
BTW, flatworms were once considered to be "primitive" bilaterians, but that hypothesis is generally out of favour now.
Didn't chordates come before vertebrates and are considered to be animals that possess a single nerve chord generally running the length of their body?They have nothing to do with chordates. Chordates include vertebrates like ourselves, plus sea squirts and their kin, and these guys. Flatworms are in an entirely different part of the animal tree and possess none of the defining features of chordates.
No, yeah, I get that. Like when people say we evolved from Chimps. Like no, we didn't... yes we have a common ancestor but neither one came from the other and since then we've both done the same amount of evolving.Again, that's an outdated idea (unless you are thinking of acoels, which - well, we're still not sure what they are, but one thing they almost certainly aren't is flatworms). Also, even if they were the furthest possible bilaterians you could find from a human vantage point, that doesn't mean "they" did anything first. That is a common misunderstanding of how phylogenies work. (It is also a giant pet peeve of mine.) The animal that first adopted bilateral symmetry would have been a common ancestor of flatworms and us. (Unless we come from flatworms, which to the best of anyone's knowledge isn't the case)
Reed Frogs and Wrinkled Frogs do this. That's all I know... so yeah, it's more common in fish.Frogs can change sex? Which ones?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?