Animal Reproduction

Asexual Reproduction A type of reproduction that only involves one parent Offspring are genetically identical to the parent because the parent is making exact copies of itself Does not involve the fusion of sex cells (gametes)

Asexual Reproduction: Pros Cons Fast Do not need a mate Requires little energy Many offspring Less genetic variability In poor conditions many or most will die off Vulnerable to disturbance Slows evolution

Sexual Reproduction Involves the union of reproductive cells (gametes) from two different parents, called fertilization and results in the formation of a zygote The union of the two gametes is called fertilization Offspring are genetically unique from either parent

Sexual reproduction: Pros Cons Genetic diversity among offspring Allows for evolution (ability to adapt) Higher survival rate Recombination can disrupt successful adaptations Huge amount of energy required to make gametes Requires more time Reliance on a mate

Asexual Reproduction in Animals Fission The division of a single parent cell into two new daughter cells of equal size

Asexual Reproduction in Animals Fragmentation the breaking of the body into multiple parts with subsequent regeneration For example, if the arm of an individual sea star is broken off it will regenerate a new sea star

Asexual Reproduction in Animals Budding the outgrowth of a part of a cell or body region leading to a separation from the original organism into two individuals In hydras, a bud forms that develops into an adult, which breaks away from the main body

Asexual Reproduction in Animals Parthenogenesis An egg develops into a complete individual without being fertilized Parthenogenesis occurs in invertebrates such as water fleas, rotifers, aphids, stick insects, some ants, wasps, and bees.

Asexual Reproduction in Animals Bees use parthenogenesis to produce haploid males (drones) and diploid females (workers or queen). The queen bee controls the reproduction of the hive bees to regulate the type of bee produced.

Asexual Reproduction in Animals Some vertebrates can also reproduce through parthenogenesis including reptiles (lizards, snakes), fish (sharks), and amphibians (tiger salamander)