Topic 6 - Inheritance and response - Annoying stuff Flashcards
(25 cards)
1
Q
What conclusions did mendel reach?
A
- characteristics in plants determined by hereditary units
- heredity units passed on to offspring unchanged from both parents - one unit from each parent
- hereditary units can be dominant or recessive
2
Q
What are the two types of variation in a species?
A
- genetic variation
- environmental variation
3
Q
How is genetic variation caused?
A
- characteristics determined by how genes inherited from parents
- combining of genes from two parents causes genetic variation - you get some genes from mother and some from father
4
Q
How do mutations introduce variation?
A
- mutations change sequence of bases in DNA
- can result in new phenotype being seen in a species
- if new phenotype makes individual more suited to new environment - can become common through species quickly due to natural selection
5
Q
What is the theory of evlolution?
A
- darwin concluded that organisms with most suitable characteristics for environment would be more successful competitors - more likely to survive - “survival of the fittest”
- successful organisms that survice more likely to reproduce - pass on genes for characteristics that made them successful to offspring
- over time beneficial characteristics become more common in population of species - it evolves
6
Q
What supported Darwins studies?
A
- phenoptype controlled by genes - new phenotypic variations arise due to genetic variants produced by mutations
- beneficial variations passed in genes that parents pass to offspring
7
Q
Why did people disagree with darwin?
A
- against common religious beliefs - against God being creator
- couldnt explain why useful characteristics appeared or how they were passed on to offspring
- wasnt enough evidence to convince many scientists
8
Q
What ideas did Lamarck have?
A
- argued changes an organism acquires during lifetime are passed on to offspring
- thought if characteristic was used a lot by organism - would become more developed during lifetime - offspring would inherit acquired characteristic
9
Q
What is selective breeding?
A
- humans artificially select plants or animals that breed so genes for particular characteristics remain in the population
- organisms are selectively bred to develop features that are useful or attractive
10
Q
Selective breeding longer answer?
A
- from existing stock - select animals with characteristics you want
- breed them with each other
- select best of the offspring and breed them together
- continue this process over several generations - eventually all offspring will have the characteristic due to variation
11
Q
Main drawback from selective breeding?
A
- reduce gene pool - the number of different alleles in a population
- inbreeding can cause health problems - more chance of organisms inheriting harmful genetic defects when gene pool is limited
- serious problems if new disease occurs - not much variation in population
12
Q
What is genetic engineering?
A
- transfering gene responsible for desired characteristic from one organisms genome into another organism
- means target organism also has desired characteristic
13
Q
Genetic engineering longer answer?
A
- useful gene cut from one organisms genome using enzymes - is inserted into vector
- vector typically virus or bacterial plasmid
- when vector introduced to target organism - usefsul gene is inserted into its cells
14
Q
Pros and cons of GM crops?
A
- GM crops reduce farmland biodiversity - transplanted genes may get out into natural environment
- characterstic for GM crops can increase yield - GM crops can help people who lack nutrition
15
Q
How can tissue culture be used to clone plants?
A
- plant cells put into growth medium with hormones - grow into new plants - clones of parent plant
- can be made very quickly in little space - grown all year - used to preserve rare plants
16
Q
How can cuttings be used to clone plants?
A
- take cuttings from good parent plants - plant them to produce genetically identical copies of parent plant
- plants can be proudced quickly and cheaply
17
Q
How can you make animal clones by using embryo transplants?
A
- sperm cells taken from prize bull - egg cells taken from prize cow - sperm used to articically fertilise the egg - embryo develops
- cloned embryos implanted into surrogate cows where they grow into baby calves
18
Q
How can adult cell cloning make a clone?
A
- remove nucleus from unfertilised egg cell - nucleus removed from adult body cell - inserted into empty egg cell
- egg cell stimulated by electric shock - makes it divide
- when embryo is ball of cells - implanted into womb of adult female - grows into identical copy or original adult body cell - same genetic information
19
Q
What are fossils?
A
- remains of organisms from many thousands of years ago found in rocks
- provide evidence organisms lived ages ago - tell us about how organisms evolved over time
20
Q
How do fossils form from gradual replacement by minerals?
A
- things like bones and shells dont decay easily - last long time
- eventually replaced by minerals as they decay - forming rock life substance shaped like orginal hard part
- surrounding sediment turns to rock - fossil stays distinct inside rock
21
Q
How do fossils form from preservation?
A
- in amber and tar pits - no oxygen or moisture - decay microbes dont survive
- in glaciers too cold for decay microbes to work
- peat bogs too acidic for many decay microbes
22
Q
What is speciation?
A
- development of new species
- occurs when populations of same species become so different - can no longer successfully interbreed to produce fertile offspring
23
Q
How does speciation happen?
A
- caused by isolation and natural selection
- each population shows genetic variation dude to wide range of alleles
- in each population individuals with characteristics that make them better adapted to their environment have better chance of survival - more likely to breed successfully
- allels that control beneficial characteristics more likely to be passed on to children
24
Q
What is antibiotic resistant bacteria?
A
- bacteria can sometimes develop random mutations in their DNA - leads to changes in characteristics
- can lead to antibiotic-resistant strains forming as gene for antibiotic resistance becomes more common in population
25
What causes antibiotic resistant bacteria?
- antibiotics dont cause resistance - they create situation where naturally resistant bacteria have advantage - so increase in numbers
- important to finish antibiotic cycle to kill all the bacteria - none left to mutate and develop into antibiotic resistant strains
