2 main forms of reproduction
- asexual
2. sexual
ASEXUAL REPRODUCTION
an organism copies its dan and splits the contents of one cell into two cells.
e.g. of organisms that reproduce asexexually
- bacteria, archea, and single celled eukaryotes( amoeba), some multicellular organism.
SEXUAL REPRODUCTION
requires 2 parents: sperm fertilizes an egg
CONJUGATION
the earliest of asexual reproduction from 3.5 bya. that involved genetic exchange
One bacterial cell uses an out growth called a SEX PILUS to transfer genetic
material to another bacterium.
. This is still prevalent today
. it is a form of asexual reproduction
negatives of sexual reproduction
attracting a mate and producing and dispersing sperm and eggs take a lot of energy.
the cons of asexual reproduction
identitical offsprings make it hard for species to adapt to a changing environment
pros of sexual reproduction
genetic variability increases the chance that at least some individuals will have a combination of traits that allow them to thrive and reproduce.
pro of asexual reproduction
litt energy is exerted to find a mate or produce gametes
How do asexual and sexual reproduction differ?
Asexual reproduction requires only one parent and produces offspring that are identical, except for mutations. Sexual reproduction requires two parents and produces genetically variable offspring.
How can asexually reproducing organisms acquire new genetic information
Mutations can create new gene variants, and some asexually reproducing organisms can acquire new genetic information by exchanging DNA. For example, conjugation can increase genetic diversity in bacteria and Paramecium
Why does sexual reproduction persist even though it requires more energy than asexual reproduction?
Sexual reproduction produces the variation needed for a population to survive a changing environment. The mutations giving rise to variation in asexual populations does give variation, but not quickly enough or in great enough degrees to be successful in a rapidly changing environment.
