Reproduction in humans
Sexual Reproduction in Humans
Did you know that gametes are formed in the sex glands? After puberty, sperm are produced continuously in the testes. This process usually continues into old age.
In contrast, females are born with all their eggs. After puberty, typically one egg is released each month. This process, called ovulation, usually stops around the age of 50.
In humans and most mammals, a special part of the mother's body supports the growth and development of the embryo. This structure is called the uterus. The embryo connects to the mother via the placenta and blood vessels that transport nutrients and oxygen, and remove waste.
Quick Fact
Human males produce sperm continuously from puberty onward, while females are born with all their eggs and release them monthly after puberty.
Important Concept
The placenta is a specialized organ that connects the developing fetus to the mother. It allows for the exchange of oxygen, nutrients, and waste without direct mixing of blood between mother and fetus.
Questions
Show Answer
It shows how one fertilized egg divides into two embryos, which develop into genetically identical twins.
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Because they come from the same egg and sperm, they have exactly the same genetic material.
Common Mistake
Many students think sperm and egg production work the same way in males and females. In reality, sperm are produced continuously, while females are born with a fixed number of eggs.
Question
3. Two populations of the same species live in the same environment. One population reproduces asexually, and the other sexually. If environmental conditions change (such as temperature, food, or disease), which population is at greater risk? Explain why.
4. Compare sexual and asexual reproduction. What are the advantages and disadvantages of each?
Show Answer
3. The asexual population is at greater risk. Since all individuals are genetically identical, a single environmental change (like a disease) can affect all of them. Sexual reproduction produces genetic variation, making it more likely that some individuals will survive changes.
4. Asexual reproduction: Faster, requires only one parent, but no genetic variation.
Sexual reproduction: Slower, requires two parents, but increases genetic diversity and adaptability.