AOS 2 Exam Revision Flashcards
advantages of asexual reproduction
Advantages
* grows faster than sexually reproducing populations
* offspring are identical clones of the parent. This is especially important for organisms that have adapted a phenotype that is fine–tuned to survive in a particular environment
* does not require an organism to find a mate to reproduce, meaning that the organism does not have to be mobile
disadvantages of asexual reproduction
Disadvantages
* genetic diversity is low and asexually reproducing populations may suffer during rapid environmental change.
* requires very little parental investment and removes the need to protect fragile offspring
advantages of sexual reproduction
Sexual reproduction
Advantages
* increases the genetic diversity of a population by allowing for recombinant offspring
Meiosis involves crossing over and independent assortment, two important processes which are essential to maintain a high degree of genetic diversity in a population.
* improves disease resistance by promoting the presence of different alleles
disadvantages of sexual reproduction
Disadvantages
* the cost of male progeny
* the time, energy, and resources it takes to attract and find a mate
* the risk of transferable diseases associated with sexual intercourse
* combining the genetic material from two gametes reduces the chances of an offspring inheriting a genetic disorder that might be carried by one parent.
* the risk of losing offspring to outside influences such as embryo damage
Reproductive cloning technologies
Reproductive cloning technologies are human interventions which artificially produce genetically identical clones of an organism.
Reproductive cloning technologies: animals Somatic cell nuclear transfer
Reproductive cloning technologies: animals Somatic cell nuclear transfer
1 Enucleation – removal or destruction of the nucleus from the donated egg cell
2 Extraction – the donated somatic cell’s nucleus is extracted
3 Insertion – the donated somatic cell’s nucleus is inserted into the enucleated egg cell
4 Development – the developing embryo is implanted into a surrogate mother
Embryo splitting Fertilisation
Reproductive cloning technologies: plants Genetically identical o spring
- Tissue culturing – growth of plant cells on a growth medium in sterile conditions.
- Plant cuttings – production of new plants from fragments such as the stem or root from the original plant.
- Plant grafting – attachment of a rootstock and scion together to produce a clone.
Genetic diversity
Genetic diversity refers to the amount of genetic variation that exists between individuals within a population. This is important in protecting the longevity of a species by reducing their susceptibility to sudden environmental changes. Populations with greater genetic diversity have a higher chance of containing alleles that are better suited to survive new environmental challenges.
structural adaptation
evolved modifications to an organism’s physical structure
behavioural adaptation
evolved modifications to an organism’s actions
physiological adaptation
evolved modifications to an organism’s internal functioning or metabolic processes
abiotic
a property of the environment relating to non living things. Examples include temperature, nutrient availability, and water availability
biotic factor
a property of the environment relating to living things. Examples include predator prey relationships, competition, and symbiotic relationships
