Chapter 38 Flashcards
(26 cards)
Asexual reproduction
when one parent makes an exact copy of itself without needing another parent.
Budding
A new organism grows off the side of the parent and then breaks off.
Fragmentation
A piece of an organism breaks off and grows into a new one.
Transverse fission
An organism splits in half sideways to make two new ones.
Parthenogenesis
An egg grows into a new organism without being fertilized.
Haploid
A cell with half the usual number of chromosomes.
Gonad
An organ that makes eggs or sperm (like ovaries or testes).
External fertilization
Eggs and sperm meet outside the body.
Internal fertilization
Eggs and sperm meet inside the body.
Gonochoric
Species where each individual is either male or female (not both).
Fertilization
When a sperm and egg join together.
Zygote
The first cell formed when a sperm and egg combine.
Hermaphrodite
An organism that has both male and female reproductive parts.
Cleavage
The first few cell divisions after a zygote is formed.
Blastula
A hollow ball of cells made after lots of cleavage.
Blastocyst
A special kind of blastula found in mammals.
Blastomeres
The individual cells formed during cleavage.
Gastrula
The stage when the hollow ball (blastula) folds inward to form layers.
Germ layer
Layers of cells in the embryo that develop into different body parts.
Ectoderm
The outer layer that forms skin and nerves.
Mesoderm
The middle layer that forms muscles, bones, and blood.
Endoderm
The inner layer that forms the gut and organs like the lungs.
Cell differentiation
When cells change to do special jobs (like becoming muscle or nerve cells).
Apoptosis
Planned cell death; the body’s way of removing cells it doesn’t need.
