inheritance; b6 variation and evoloution Flashcards
what is variation?
differences in the characteristics of inddivulas in a population
what are the three main causes of varition?
- the alleles which the individual have inherited(genetic)
- the conditions they have devoloped in ( enviromental)
- a combonation of genese and the enviroemnt
do mutations affect the phenotype?
**most have no effect but some **affect the phenotype and **very few **determine the phenotype
what can lead to rapid changes in the species?
if the new phentype cause by the mutation is suited to an enviroemntal chnage it will lead to rapid chnages in the sepcicies.
what is the definition of evoloution?
change in the inherited chacteristics of a population overtime through a process of natural selection
what does the theroy of eveolution by natural selection state?
states that all species of
living things have evolved from simple life forms that first developed
more than three billion years ago
what is genotype and what is phenotype?
whta happnes when 2 animals become so different in phenotype?
thye can no longer interbreed
what is selcetive breeding?
slective breeding is the process which by huamns breed plants and animals fornparticaular genetics
how is selective breeding done?
- choosing both parents with the best ofbthe desired characteristics
- they are bred together
- their offsprings with desired chacateristics are bred together
- continues over many generations until all offpsrings show desired chataeristics
what is selective breeding chosen for?
- Disease resistance in food crops.
- Animals which produce more meat or milk.
- Domestic dogs with a gentle nature.
- Large or unusual flowers.
what are the implications of selective breeding?
can lead to inbreeding where some breeds are prone to disease or inherited defects
what is gentic engeneering?
gentic engeneering is the process of modifying the genome of an organism by introducing another gene to get a desired characteristic.
how have both plants crops and bacteria been genetically modified?
- plants gentically engineered to be resistant to diseases and to make bigger fruits.
- bacteria has been gm to produce useful substances such as human insulin to treat diabetes
tell me the stages of genetic engineering?
* enzymes are used to isolate the required gene; this gene is inserted into a vector, usually a bacterial plasmid or a virus
* the vector is used to insert the gene into the required cells
* genes are transferred to the cells of animals, plants or microorganisms at **an early stage in their development **so that they develop with desired characteristics.
what are concerns about gm crops?
effect on populations of wild flowers and insects. Some people feel the effects of eating GM crops on human health have not been fully explored.
what is medical conern about genetic engeneering?
- unknown long-term effects, and there is a possibility that it may lead to undesirable changes or even new health problems.
- ethical concerns is it good or bad
what is tissue culture?
using a samll group of cells form a plant to grow idenitcal new plants
why is tissue culture used? or important?
with tissue culture we can preserve rare plant sepcies
what is the cutting method to produce identical plants?
used to produce only some clones not for a lot
Cuttings: an older, but simple, method used by gardeners to produce some identical new plants from a parent plant.
* you take a cutting from a plant witht the desired chateristics
* cut some of it and put the roots into hormone rooting powerder this encourages the plant to devolp roots
how is tissue culturing done?
- take many small peices of a plant which have cells in them
- place them into an incubator with plant hormones
- hormone sstimualte plants to grow and clone fully grown plants
*
what are conditions for tissue cultuire?
sterile so no microogisnm or basicteria is introduced
what is embryo transplants?
splitting apart cells from a developing animal
embryo before they become specialised, then transplanting the identical embryos into host mothers.
how do we do embryo transplants? (very common question)
- start with sperm and egg cell with desired charcteristcs
- fertilise the egg and allow it to devolp into an early stage embryo (imporant they dont specilaise)
- then split the embroy with a glass rod into 2
- transplant the 2 embroys into host mothers
what is the problem with embro tranplant?
sont know if we will get desired chacateristics as we start with the egg and the sperm.
thats why adult cloning is better
how can we do adult cloning?
- The nucleus is removed from an unfertilised egg cell.
- The nucleus from an adult body cell, such as a skin cell, is inserted into the egg cell.
- An electric shock stimulates the egg cell to divide to form an embryo.
- These embryo cells contain the same genetic information as the adult skin cell.
- When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development
