The evolution of human reproduction is an interesting subject! But has reproduction evolved?
Evolution needs millions of years to get things right – if reproduction is not right the species dies out after one generation.
The evolution of a reproductive system is surely irrelevant until it becomes fully functional, but how do cells know what to do without a plan?
The process of reproduction is amazingly complex and must have been perfect right from the beginning to be successful.
1. How has sexual reproduction evolved – Evolution’s point of view
How did sexual intercourse evolve when both male and female forms need to be available?
On a Wikipedia document entitled: ‘Evolution of sexual reproduction’ (Wikipedia’s policy isn’t to reveal author’s name) and which had a bizarrely named web address: “Evolution of sexual reproduction = The evolution of sexual reproduction, being incapable of reproducing asexually. Sex however has evolved as, into the tree of life.”
On this Wikipedia page, it states:
Prior to the advent of sexual reproduction, the adaptation process whereby genes would change from one generation to the next (genetic mutation) happened very slowly and randomly.Wikipedia ‘Evolution of sexual reproduction’ 1
Sex evolved as an extremely efficient mechanism for producing variation, and this had the major advantage of enabling organisms to adapt to changing environments.”
That is a very sweeping statement, how exactly can sexual organs evolve and end up at the correct shape and size and then start to function producing sperm and eggs?
Further down this massive Wikipedia page which contains lots of speculation but no real answer, it says:
The origin of sexual reproduction can be traced to early prokaryotes, around two billion years ago (Gya), when bacteria began exchanging genes via conjugation, transformation, and transduction. 2Wikipedia ‘Evolution of sexual reproduction’
Though these processes are distinct from true sexual reproduction, they share some basic similarities.
In eukaryotes, true sex is thought to have arisen in the Last Eukaryotic Common Ancestor (LECA), possibly via several processes of varying success, and then to have persisted (compare to “LUCA”). 3
If you are interested:
- Eukaryotic cells = cells of animals, plants and fungi.
- Prokaryotes cells = Bacteria which are single cells, the simplest of organisms.
- LUCA means: The Last Universal Common Ancestor or Last Universal Cellular Ancestor also called the Last Universal Ancestor (LUA), is the most recent population of organisms from which all organisms now living on Earth have a common descent—the most recent common ancestor of all current life on Earth. 4
For me, the Wikipedia article still does not answer the question: “Has reproduction evolved?”
They obviously say yes to the question but they haven’t got any solid answers.
An article entitled: “Scientists put sex origin mystery to bed” by Jeanna Bryner from NBC News using LiveScience as her source states:
We all came from hermaphrodites, organisms with both male and female reproductive organs.NBC News “Scientists put sex origin mystery to bed” 5
And though the origin traces back more than 100 million years, biologists have scratched their heads over how and why the separate male and female sexes evolved.
Now, research on wild strawberry plants is providing evidence for such a transition and the emergence of sex, at least in plants.
And the results, which are detailed in the December issue of the journal Heredity, likely apply to animals like us, the researchers say.”
Is it really something that could evolve by chance over millions of years before it became successful – surely everything would have died out before it had become successful?
Again this seems like grabbing at bizarre ideas just so that people can say that reproduction has evolved.
Richard Dawkins is a British evolutionary biologist and author. He is an atheist and is well known for his criticism of creationism and intelligent design, he admitted:
To say, as I have, that good genes can benefit from the existence of sex whereas bad genes can benefit from its absence, is not the same thing as explaining why sex is there at all.‘Climbing Mt. Improbable’ by Richard Dawkins 6
There are many theories of why sex exists, and none of them is knock-down convincing …
Maybe one day I’ll summon up the courage to tackle it in full and write a whole book on the origin of sex.”
2. Are testicles badly designed?
Oxford University Ph.D. Professor Hafer thought she had found evidence to prove that creation was wrong:
Hafer explained that when she was looking for new approaches to refute Intelligent Design, she knew she ‘had a winner when … in the middle of an Anatomy and Physiology lecture’ she concluded that the male reproduction system ‘is a great first argument against ID’. 7‘Is the male reproductive system poorly designed?’ by Jerry Bergman 8
She believed that she also had a good ‘political-style argument’ against ID.
Her main argument is that because male testicles are outside of the body, they are prone to injury.
She adds that in many animals, including cold-blooded reptiles, they are located inside the body where they are fully protected.”
But unfortunately, she went straight into trying to kick Intelligent Design rather than ask the question; ‘Why are the testicles like this?’
Jerry Bergman, PhD in Biology, has taught biology, genetics, chemistry, biochemistry, anthropology, geology, and microbiology at Northwest State College in Archbold OH for over 25 years. He has 9 degrees, including 7 graduate degrees. 9
He explains why testicles are outside of the body:
Male testicles exist outside of the body in humans and most mammals for several important reasons, including effective regulation of scrotal temperature for optimal spermatogenesis development.‘Is the male reproductive system poorly designed?’ by Jerry Bergman 12
Another reason is to keep sperm relatively inactive until they enter the warm confines of the female reproductive system.
Even just a few degrees above the optimal temperature is detrimental to both sperm production, specifically in the later stages of spermatogenesis, and sperm maturation… 10
If the testes were inside the body, the enzymes sperm require to be healthy would be denatured in a matter of hours…
This issue would not be a concern for most animals that are fertile only during very short windows each year.
Furthermore, to maintain the proper temperature, the arteries carrying blood into the scrotum run alongside the veins that carry blood away.
This sophisticated heat-exchanger mechanism lowers the temperature of the blood supply travelling to the testicles.” 11
So the testicles are carefully designed.
3. What Creationists say about the evolution of reproduction
The occurrence of sexual reproduction is commonplace‘The origin of gender and sexual reproduction’ by Brad Harrub and Bert Thompson 13
throughout the animal kingdom, and with humans as well.
Yet evolutionists have not scientifically explained its existence. The Darwinian ‘survival of the fittest’ mantra does not
compute with a sexual practice that selectively only passes
one half of one’s genes to successive progeny.
Consider that sexual reproduction necessitates the existence of sexual chromosomes and an entirely new physiological method for cell division.
Additionally, science has not satisfactorily explained the differences among various species, (e.g. why the male seahorse gives birth, when it is primarily the female in other species that gives birth) or the vast differences between
animal and human sexuality (e.g. oestrus cycle vs. menstrual cycle).
Even within human kind, one must ask how and why male and female genders exist.”
Evolution cannot explain how sexual reproduction has evolved, but Christians believe that God, the designer, put into place a huge diversity within the DNA structures.
Many single-celled organisms reproduce asexually.‘Evolutionary theories on gender and sexual reproduction’ by Bert Thompson and Brad Harrub 15
If we all descended from these single-celled creatures, as Margulis and Sagan have suggested, then why was the simple-yet-efficient method of asexual reproduction set aside in favour of sexual reproduction?
Dobzhansky and his co-authors commented on this ironic difficulty in their book, Evolution:
‘With respect to the origin of sexual reproduction, two challenging questions present themselves.
First, in what kinds of organisms did sex first arise?
And second, what was the adaptive advantage that caused sexual reproduction to become predominant in higher organisms?’ 14
Asexual reproduction is the formation of new individuals from cells of only one parent, without gamete formation or fertilization by another member of the species.
Asexual reproduction thus does not require one egg-producing parent and one sperm-producing parent.
A single parent is all that is required.
Sporulation (the formation of spores) is one method of asexual reproduction among protozoa and certain plants.
A spore is a reproductive cell that produces a new organism without fertilization.
In certain lower forms of animals (e.g. hydra), and in yeasts, budding is a common form of asexual reproduction as a small protuberance on the surface of the parent cell increases in size until a wall forms to separate the new individual (the bud) from the parent.
Regeneration is another form of asexual reproduction that allows organisms (e.g. starfish and salamanders) to replace injured or lost parts.”
I know that pro-evolutionists would say that I am grabbing at the Creation idea of it being made that way right from the start, or at least the blueprint is within the DNA, and that requires a lot of blind faith to think that.
But I would say that it requires an even greater amount of blind faith to believe that reproduction has evolved.
I suggest that the ability to reproduce was put in place right from the beginning by God the Great Designer.
References – open in new tabs:
R. Dawkins, Climbing Mt. Improbable (Harmondsworth, Middlesex, England: Penguin Books Ltd., 1997), p. 75. ↩
Hafer, A., No data required: why intelligent design is not science, The American Biology Teacher 77(7):507–513, 2015; Hafer, ref. 2 p. 2. ↩
Setchell, B.P., ‘The effects of heat on the testes of mammals, Animal Reproduction’ 3(2):81–91, 2006. ↩
Wechalekar, H., Setchell, B.P., Peirce, E.J., Ricci, M., Leigh, C., and Breed, W.G., ‘Whole-body heat exposure induces membrane changes in spermatozoa from the cauda epididymis of laboratory mice’, Asian J. Andrology 12(4):591–598, 2010. ↩
Dobzhansky, T., Ayala, F.J., Stebbins, G.L. and Valentine, J.W., ‘Evolution’ W.H. Freeman, San Francisco, p. 391, 1977 ↩