Inheritance, Variation and Evolution Flashcards
How is genetic variation created?
through mutations
What is a mutation?
change in the DNA code
What is natural selection?
fittest individual due to mutation is more likely to survive and reproduce
Which two factors contribute to the variation between organisms?
mutations and natural selection
What is speciation?
the process in which a species evolves to become another species
What was Lamarck’s theory?
an organism could acquire new traits during their lifetime, and these traits would be passed onto their offspring
What was Darwin and Wallace’s theory?
the variation in species means that the more favourable traits allow the organisms to survive and reproduce more, spreading throughout the population
What were 3 reasons people didn’t accept Darwin and Wallace’s theory?
religious reasons, lack of evidence, DNA hadn’t been discovered yet`
According to Darwin and Wallace’s theory, why do giraffes have long necks?
Giraffes with longer necks were better adapted to their environment
According to Lamarck’s theory, why do giraffes have long necks?
Giraffes acquired longer necks during their lifetime and passed this trait to their offspring.
What is selective breeding?
taking the best plants or animals and breeding them together in hopes to get a better offspring
What is a drawback of selective breeding?
reduces the gene pool of the population
What type of variation can be passed on to the next generation?
Genetic variation
What effect does selective breeding usually have on variation within a population?
It decreases variation
What is the term used to describe all the genes and their alleles found in a population?
genepool
What is the term used to describe the breeding together of closely related individuals?
inbreeding
What is genetic engineering?
modifying an organism by changing their genome for a benefit
What is gene therapy?
giving a person a healthy version of the gene that is causing the illness
What is one reason gene therapy is very difficult?
the faulty gene is in every cell of the body so we would have to transfer the healthy gene into every cell in the body.
How do you trasfer a gene from one organism to another?
1) you isolate the gene you want from the organism
2) you put it in a vector (virus of bacterial plasmid)
3) you make the other organism take up the vector and with it the gene.
What is the Human Genome Project (HGP)?
a major international research effort aimed to map out the entire human genetic code
How many genes has the HGP identified?
around 20,500 human genes
How many human genes have been found to be linked to diseases?
2,000
How do you clone an organism?
1)take an egg cell of the donor female and remove its nucleus
2) take an adult body cell and remove its nucleus
3)Put the body cell nucleus into the egg cell
4)Stimulate the cell to start dividing and forming an embryo.
5)Implant the embryo into a surrogate mother and wait for it to be born like normal.
What do you call a cell with its nucleus taken out?
enucleated cell
what is a clone?
an individual which is genetically identical to another individual
What is a transgenic organism?
an organism with DNA from another organism
How do you clone an embryo?
1) Pick the two organisms (of the same species) that have the most desirable traits
2)take sperm and use it to fertilise the egg.
3) let the zygote develop into an embryo
4) Separate the embryo into smaller embryos
5) Implant each embryo into a surrogate mother and the offspring will all be clones`
How do you clone a plant through cuttings?
1) find a plant you want to clone
2) Cut off a small part (ideally a growing shoot or branch)
3) Place the cutting in soil with nutrients
4) the cutting will grow into a clone of the original plant