Human Body Chapter 5-1

In humans, each egg and each sperm contain _______ chromosomes.

23 chromosomes.

Name two ways that all mammals are alike.

All mammals reproduce sexually and nurture their young with milk.

Why is reproduction as important to a bristlecone pine as it is to a fruit fly?

Every living organism is a member of a species. Every living organism eventually dies, so in order for a species to survive, individual organisms must reproduce.

What is the difference between external and internal fertilization?

External fertilization is when sex cells unite outside of the female body while internal fertilization is when the sex cells unite inside the female body.

Are humans placental mammals, monotremes, or marsupials? Explain.

Humans are placental mammals because they nourish their young internally before giving birth to live young.

Describe one advantage of internal fertilization over external fertilization.

Internal fertilization allows the female to protect the developing egg inside her body.

How do monotremes differ from marsupials?

Monotremes lay eggs but marsupials give birth to live young.

What is sexual reproduction?

Sexual reproduction is reproduction in which the sex cells (egg and sperm) of two parents unite to form a new individual

Describe the process of meiosis.

When a male of a female sex cell that has 46 chromosomes divides into 4 eggs of 4 sperm that have 23 chromosomes each.

egg:

a sex cell produced by a female

List three types of asexual reproduction.

budding fragmentation regeneration

internal fertilization:

fertilization of an egg by sperm that occurs inside the body of a female (ex- mammals)

sexual reproduction:

reproduction in which sex cells from two parents unite to produce offspring that share traits from both parents

asexual reproduction:

reproduction that does not involve the union of sex cells and in which a single parent produces offspring that are genetically identical to the parent (ex-starfish)

sperm:

the male sex cell

external fertilization:

the union of sex cells outside the bodies of the parents (example-frogs, female releases eggs while male releases sperm over the eggs to fertilize them.)