Reproduction Flashcards
Asexual reproduction
The production of offspring that does not involve the fusion of gametes. Usually produces clones.
Fragmentation
When a multicellular organism splits into pieces and each new piece develops into a new organism
Give an example of an organism that reproduces using fragmentation
Starfish, marine worms, flatworms
Budding
When an organism, such as yeast, forms a growth that develops into a new organism and then breaks off
Give an example of an organism that reproduces using budding
Yeast and hydra
Spores
Spores are haploid cells that can develop into a new organism
Parthenogenesis
The development of an egg cell in the absence of fertilization
Give an example of an organism that reproduces using parthenogenesis
Some lizards, birds and insects
Vegetative reproduction
The growth of specialized plant tissue such as rhizomes, runners, tubers or bulbs that can grow into a new plant if it becomes separated from the parent plant
Disadvantages of asexual reproduction
Asexual reproduction produces clones, they are genetically identical, so the population has a low genetic diversity
This means that if the environment and selection pressures change e.g. new pathogen then all of the population of clones are likely to not survive
Advantages of asexual reproduction
Offspring genetically identical to parent so are well suited to a stable environment.
Does not require a mate.
Define sexual reproduction
Sexual reproduction is the fusion of gametes to produce offspring that are genetically different.
Give an advantage and disadvantage of sexual reproduction
Sexual reproduction allows there to be more genetic variation in the offspring so they are more likely to survive in a changing environment with different selection pressures.
However crossing over in Prophase I forming the gametes, could break apart beneficial allele combinations, and whilst the gametes will be varied, they may not be more likely to lead to survival.
Another disadvantage would be sexually transmitted diseases can pass between individuals in the population.
Name the two methods of cloning animals
Embryo splitting,
Somatic cell nuclear transfer
Cloning
Any method of producing a clone (genetically identical copy of an organism)