Asexual Reproduction

​Involves one parent

It creates a large thriving population but faces massive die-off if conditions change.

The offspring that is produced has limited ability to adapt.

Sexual Reproduction

​Involves two parents

The offspring is a genetic mix of both parents which results in a lot of variations within a specie.

Fertilization

​The joining together of two different sex cells.

1. When the egg becomes fertilized, a new individual called ''ZYGOTE'' develops.

2. Fertilization may be external or internal.

https://youtu.be/5EvnCzOpy2o
Fertilization Process | Reproduction in Animals

​External Fertilization

1. Occurs outside the body of a female

2. Usually happens in wet environment

3. Egg are exposed to the environment

4. Has lower survival rate

5. Examples: bony fishes, and amphibians.

Internal Fertilization

Comparison of Internal and External Fertilization.

1. Occurs inside the body of a female

2. Needs to have protection for developing egg cells

3. Fertilized egg or embryo is protected from predators and harsh environment

4. Has higher survival rate

5. Examples: reptiles, birds, and mammals

Method of Internal Fertilization

​Oviparous Viviparous Ovoviviparous

• Egg laying mammals

Examples:
Birds Insects
Lizards Reptiles
Chicken Most fish

• Born alive

Examples:
Humans
Cats
Dogs
Horses

• Eggs retained in the female but the embryo obtains its nourishment from the egg's yolk. Eggs hatch within the body.

Examples:
Rattlesnakes
Some reptiles
Fish

Wrap Up