asexual reproduction vs. sexual reproduction
Post on 24-Feb-2016
91 Views
Preview:
DESCRIPTION
TRANSCRIPT
ASEXUAL REPRODUCTION
VS. SEXUAL
REPRODUCTION
ASEXUAL REPRODUCTIONOne Parent RequiredDoes NOT Require Gametes (sex cells)Offspring produced by cell division.Offspring identical to Parent (Identical DNA)Several Different Types
Binary FissionBudding Regeneration/FragmentationVegetative PropagationSporulation
BINARY FISSIONOrganisms Divide in Half
2 Identical daughter cells produced.Daughter cells are half the parent’s size.Daughter cells grow and then divide into
two new identical cells.This occurs in bacteria.
BUDDINGSmall bud grows out of parent cell
Two different sized cells made (with identical DNA)
Bud breaks off and growsThis occurs in yeast and hydra
REGENERATIONRepair/ grow lost body parts
Left over cells divide to make more cellsOccurs in Lobsters, starfish, lizards
FRAGMENTATIONA single parent breaks into
parts that regenerate into whole new individuals.
VEGETATIVE PROPAGATION
Occurs only in plants (vegetative).New plants develop from the roots,
stems, or leaves of the parent plant.
SPORULATIONSpore Formation
• Spores are produced and each spore develops into offspring which are identical to parent
• Spores are surrounded by a tough coat to help them survive harsh environmental conditions.
• This occurs in fungi, green algae, molds and non flowering plants (e.g. ferns)
SEXUAL REPRODUCTION
Sexual reproduction is the production of offspring using gametes (sex cells). Requires two parents that each share ½ of the
genetic information.Offspring share the characteristics of each parent.
The cells of the offspring have two sets of chromosomes (one from each parent), so are diploid.
Haploid = half the number of chromosomes. Human haploid cells have 23 chromosomes
Diploid= 2 of every chromosome Human diploid cells have 46 chromosomes.
Results in offspring that have a variety of traits that are similar to the parents, but not exact copies!
11
FERTILIZATIONInternally (inside)
The egg is fertilized by sperm inside the female
Mammals, birds, reptiles, insects, spidersExternally (outside)
The egg is fertilized by sperm outside the female
The female lays the eggs and then the male fertilizes them.
Fish and some amphibiansPlants and fungi (pollen and spores)
POLLINATIONpollen grains from the anther are transferred to
the stigma by the process of pollinationself pollination (plant pollinates its own eggs)cross pollination (pollen from one plant pollinates another
plants eggs)flowers are designed to lure insects to help
with the pollination processalso wind, animals, birds can transport pollen
SOME ORGANISMS DO BOTHmost plants that produce seeds (sexual
reproduction) can also reproduce asexually by things like cuttings or runnersthis gives them an advantage for survival sponges and hydra mosses
WHICH IS BETTER?IT DEPENDS!
Asexual Reproduction
advantages• does not require special
cells or a lot of energy• can produce offspring
quickly• in a stable environment
creates large, thriving population
disadvantages• limited ability to adapt• face massive die-off if
environment changes
Sexual Reproduction
advantages• lots of variation within a
species• able to live in a variety of
environmental settings• able to adapt to changes
in the environmentdisadvantages
• needs time & energy• produce small populations
top related