Asexual Reproduction
Key Terms and Concepts
asexual reproduction -reproduction that requires only one parent and produces offspring that are genetic copies of the parent
- occurs naturally in living things through a variety of methods, including: binary fission, budding, fragmentation, vegetative reproduction, and spore formation
Asexual reproduction advantages
| Asexual reproduction disadvantages
|
Large numbers of offspring are reproduced efficiently from only one parent when conditions are favourable | Offspring are genetic clones. A negative mutation can make asexually produced organisms susceptible to disease and can destroy large numbers of offspring |
Large colonies can form that can out-compete other organisms for nutrients and water | Some methods of asexual reproduction produce offspring that are close together and compete for food and space. |
Large numbers of organisms mean species may survive when conditions or the numbers of predators change | Unfavourable conditions such as extreme temperatures can wipe out entire colonies. |
Energy is not required to fond a mate |
|
clone -identical genetic copy of its parent
unicellular -organisms that are one celled
binary fission -form of asexual reproduction in which a single parent cell replicates its genetic material and divides into two equal parts
- how one celled eukaryotic organism like the amoeba reproduce
- only method of reproduction for some types of bacteria which does not have a nucleus as they don’t go through Mitosis
- term comes from the Latin words binarius, meaning two together, and fissio, meaning to split
- mutation may happen when errors occur during DNA replication or when chromosomes fail to move into new cell
- the DNA in bacteria can mutate rapidly leading bacteria to be resistant towards antibiotics
budding -form of asexual reproduction in which areas of an individual may undergo repeated mitosis and cell division and can develop into an identical organism
- advantageous for animals such as sponges
- occurs in multicellular organisms such as hydra
- occurs in unicellular organisms like yeast
fragmentation -from of asexual reproduction in which each fragment of an organism develops in clone of its parent
- if an organism breaks apart as a result of injury, each fragment then develops into a cline of its parent
- some animals, such as certain species of sea stars, can reproduce asexually from fragments
- plants can also reproduce by fragmentation provided that their environment stays static and have enough nutrients
vegetative reproduction -reproduction in which special cell divide repeatedly to form structures that will eventually develop into a plant identical to the parent
- usually in plant stems and plant roots,
- humans benefits to vegetative reproduction
- asexual reproduction of plants has benefitted humans for centuries
- provides crops for people
spore formation spore producers rely on water or wind to carry the spores away from the parent
spores -reproductive cells that grow into new individuals by mitosis
human-assisted cloning
- each sell has the potential to grow into an identical plant, researchers can clone plants from cuttings
- less complex animals like sponges, hydras, and worms can clone themselves by asexual methods
- used to save genetic information from endangered animal species or to mass-produce an organism with a desired trait
reproductive cloning
- also called DNA cloning
- purposed to produce a genetic duplicate of an existing or previously existing organism with desirable qualities
therapeutic cloning
- used to correct health problems
- to produce specialized tissues or organs for transplants
- both human embryonic stem cells and adult stem cells can be used for this purpose
stem cells -cells that have the potential to become many different types of cells
- two types of stem cells are embryonic cells and adult stem cells
- adult stem cells are not as adaptable
- embryonic cells are used in therapeutic cloning
- can be used to regenerate nerves and heart tissues to treat diabetes
embryonic stem cells -cells that can become any one of a sexually reproducing organism’s body cells
- often used in therapeutic cloning
- being able to use adult stem cells would eliminate concerns about the use of embryonic stem cells