Reproduction Notes. I. Asexual Reproduction Definition – reproduction without sex! A partner is...
-
Upload
laureen-osborne -
Category
Documents
-
view
224 -
download
2
Transcript of Reproduction Notes. I. Asexual Reproduction Definition – reproduction without sex! A partner is...
Reproduction Notes
I. Asexual Reproduction Definition – reproduction without sex! A
partner is not needed and there is no exchange of DNA.
Benefit – fast and easy!
Drawback – no genetic diversity; your offspring are identical to you EVERYTIME!
Examples of Asexual Reproduction
A. Regeneration
B. Formation of Spores
C. Plant Asexual Reproduction
II. Sexual Reproduction
Definition – creating an organism by combining the genetic material of 2 organisms. Fusion of gametes.
Gametes are reproductive cells (sperm or egg)
Benefits – produces DIVERSITY in a species
Drawback - slow and sometimes difficult
Examples of Sexual Reproduction
BACK TO HUMANS
Sperm Cells Contribute half of father’s DNA (23 chromosomes) Formed during a process of cell division called
meiosis The combination of genes is different in every
single sperm
Egg Cells (Ova) Contribute half of mother’s DNA (23
chromosomes) Also formed during meiosis Each egg is different!
Fertilization fusion of egg and sperm forms a cell called a zygote
(egg) 23 chromosomes + (sperm) 23 chromosomeszygote with 46 chromosomes
Identical Twins One sperm One egg Zygote splits in 2 Same DNA
Fraternal Twins 2 eggs 2 sperm Each develops into
a baby with a unique set of genes and traits!
Formation of the Fetus The zygote goes through a series of cell
divisions called mitosis. Cells eventually differentiate into different cell
types.
Gender Father determines baby’s gender Men XY and Women XX
50% chance of either!