Notes Flashcards
Sexual reproduction
2 different parents are required
Mixing of 2 sets of DNA
Offspring are always different from parents-genetic diversity
Process of bringing nonidentical gametes together
Mating
Members of the opposite gender come together at a certain time of the year to reproduce/mate; during the most favourable time of the year to ensure the best possibility for survival of the offspring (food, climate, temperature, weather, etc.)
Fertilization
Gametes come together to form a zygote which becomes an embryo
(Only one sperm to combine with egg/ovum-insures the correct amount of chromosomes)
Conditions for cell division
Nutrients
Temperature
Moisture
Advantages of external fertilization
Little energy used to find a mate
Large number of offspring is produced
Disadvantages of external fertilization
Most young will die
Unprotected
Parents abandon offspring
Advantages of Internal fertilization
Developing young are protected inside parent
Greater parental care
Fewer zygotes
Disadvantages of internal fertilization
Fewer offspring
Developlement
Zygote divides to form embryo through mitosis
Embryonic developlement
Early development of an organism
Morula
After the first week of cell division (week 1)
Ball of cells
Blastula
After the 2nd week which forms a hallow ball
Gastrula
Three layers of cells form-stem cells start to differentiate into specialized cells
