Like Yin and Yang, one would have to say that males and females evolved simultaneously... and there is no male without a female.
In evolution asexual replication would have evolved before sexual replication. For example, bacteria (prokaryotes) are considered to be earlier on the evolutionary tree than eukaryotes (yeasts, molds, and all plants and animals).
The Bacteria divide asexually. However, they are also able to share genes via plasmids as well as picking up environmental DNA.
In a sense, the sharing of plasmids is similar to sexual reproduction, with the entire bacteria resembling the oocyte, and having all organelles to support life. The plasmid would resemble the spermatocyte, only having what is necessary to transmit its genes, and lacking the other cellular organelles. Note, while spermatocytes have mitocondria, for example, they do not transmit mitochondrial DNA to the oocyte.
However, the stability of the genome which would be necessary for the evolution of higher organisms would have required the development of a method not only to share genes, but to also maintain a relatively fixed genome arrangement, and thus the development of the very complex meiosis. Again, it probably would have been developed simultaneously with a mutual method for males and females to share half their DNA (except for the mitochondrial DNA that only comes from the female).
If one looks at the equine species. Different members of the equine species have different numbers of chromosomes and different distributions of genes on the chromosomes. And, while they can interbreed and produce viable first generation offspring, this creates unpaired chromosomes and the offspring are unable to undergo meiosis as would be required for producing second generation offspring.
The Homo Sapien species points back to a "Mitochondrial Eve" approximately 200,000 years ago from which all living humans derive. Neanderthal man became evolutionary distinct from Homo Sapiens around that time, but co-existed with humans for over 100,000 years more. There is no evidence of significant interbreeding of the two hominid species, perhaps because of not being able to produce viable second generation offspring just like horses and donkeys are unable to have second generation offspring.
It is likely that a chromosomal shift occurred either in a single step, or rapid succession during the time of Mitochondrial Eve that necessarily excluded interbreeding with Neanderthals. This shift would have occurred in a single tribe or family, but would have symmetrically affected both males and females of the tribe or family, with no true distinction between the males or females coming first other than an unknown firstborn in the family.
Oddly the human male lineage ("Y" Chromosome Adam) is only about 60,000 years old, and is much younger than mitochondrial Eve. Certainly "Adam" would have had ancestors with lineages tracing back to Eve's time. But, about 60,000 years ago a line of dominant males evolved which effectively was able to out compete all other homo sapien males to the point that over time it became the only surviving male bloodline.
It wouldn't be unexpected though if one considers polygamous animal species in which most females of "breeding age" eventually breed, but many males never have offspring, thus female lineages would have greater diversity than male lineages.
OR the Big bang theory, we were fish originally, then we evolved :)
The frog came first, because when God created the Earth He made all of the animals and THEN the humans.
That is hard to say because humans and bovines have different lineages. We are related to them in the fact that we are both mammals but our lines separated a very long time ago.
Numerous differences can be seen between frog blood and human blood. Perhaps the most obvious is the oval shape of the frog erythrocytes rather than the biconcave discs of human blood. Moreover, the frog erythrocytes have a nucleus (here stained blue) whilst human erythrocytes do not. There is less difference in size between the erythrocytes and leucocytes than in human blood. There are no platelets in frog blood.
The axial and appendicular both make up a frog and human's skeletal system. For a frog, the skeletal system's main function is locomotion and maintaining posture. Although the human and frog skeletal system also protect vital organs the frog does not have any ribs whereas a human does. The frog also has less number of vertebrae, extended pelvic bones, and long bones of the hind legs. The frog skeletal system has l59 and the human has 206. The human's skeletal system is a moveable frame and is an efficient factory for producing red blood cells. The frog's skeletal system also produces red blood cell and all their bones are covered with a membrane called the periosteum from which they get their circulation nerves.
It depends on the length of the frog's life. I would say on average 30-75 days.
The brain and spinal cord of a human are protected by a triple layer of membranes called meninges; the meninges of the frog have only 2 layers. Human brains are more developed that those of amphibians and contain a cerebral cortex which the frog lacks. A human has 30 pairs of spinal nerves, while a frog has only 10.
The negative impacts that humans are having on the frog population are destroying their habitats so they have nowhere to breed or to hide from predators.
depends on the frog. a regular tree frog wont kill it but if somehow a poison dart frog came in contact or was eaten by a moose it would kill it from the poison there are probably a bunch of differant frogs that can do that but the poison dart frog came to mind first and is the most poisones frog there is.
There are a few anatomical differences between the digestive system of a human and a frog. The first is that there are no villi in the small intestine of a frog. Frogs also have very weak teeth. The GI tract of the human and frog are also very different.
hominids
Frog came from Bali in Asia.
no it is not
A human's blood quality is better because it has more heart chambers than a frog does. A frog has 3 chambers and a human has 4
The Leap Frog Learning System first came out in the summer of 2011. There are different educational programs for different age group, and the price vary accordingly.
Humans came after Dinosaurs.
I tried some for the first time, now have a red rash on my side, the only thing I can think of is it came from trying the frog legs
A human's blood quality is better because it has more heart chambers than a frog does. A frog has 3 chambers and a human has 4
the first human in space, Yuri Gagarin, came from the USSR.
tutankhamen