Topic 4 - Natural Selection and Genetic modification Flashcards

Question

How did Charles Darwin come up with the theory of evolution by natural selection?

Answer 1

5 Year voyage on HMS Beagle studying plants and animals -> Noticed there was variation in memers of the same species and that those with beneficial characteristics were more likely to survive -> Noticed these could be passed down onto offspring

Answer 2

A scientist working at the same time as Darwin, who also came up with the idea of natural selection

Answer 3

Published their papers on evolution together -> Although they didnt always agree on the mechanisms on natural selection

Answer 4

Helped to support the theory of evolution by natural selection -> E.g. He realised that warning colors are used by some species to stop predators eating them (butterflies)

Answer 5

"On the Origin of Species" - Darwin, Published in 1859 | Partly why Darwin was better remembered than wallace

Answer 6

Classification Antibiotic resistance Conservation

Answer 7

If all living organisms have descended from a common ancestor, then we're all related in some way. -> we now classify organisms based on how closely related they are

Answer 8

We understand the importance of finishing the course of drugs to prevent resistant bacteria spreading and we know we need to constantly develop new antibiotics to fight newly evolved resistant bacteria

Answer 9

Understand the importance of Genetic diversity and how it helps populations adapt to changing environments -> Lead to conservation projects

Answer 10

Human beings and their ancestors they evolved from 6 million years ago

Answer 11

That they both evolved from a common ancestor 6 million years ago

Answer 12

**Ardi is a fossil of the species Ardipithecus ramidus** -> Found in Ethiopia -> 4.4 Million years old

Answer 13

1) Structure of **feet** suggests she climed trees -> Ape like big toe to grasp branches 2) Long arms and short legs - more ape than human 3) Brain size - similar to Chimpanzees 4) Structure of** legs suggests she walked upright** 5) Hand bone structure suggests she didnt use her hands to walk

Answer 14

**Lucy is a fossil of the species Australopithecus aferensis** -> Found in Ethiopia -> 3.2 Million years old -> Mixture of human and ape features, more human-like than Ardi

Answer 15

1) Arched feet - more adapted to walking than climbing - no ape-like big toe 2) Size of arms and legs was between an apes and a humans 3) Brain slightly larger than Ardi's but still Chimp like 4) Structure of Bones and feet suggest she walked upright, but more efficiently than Ardi

Answer 16

1984 Scientist Richard Leaky -> They discovered many important fossils of Australopithecus and homo species

Answer 17

Turkana Boy

Answer 18

1.6 Million years old skeleton of the species homo erectus -> Mixture of human and ape features, more human than Lucy

Answer 19

1) Short arms and long legs - more human than ape 2) Larger brain size - more human 3) Structure of feet and legs suggested he walked upright - more effeciently than Lucy

Answer 20

1) reduces gene pool - number of different alleles in a population 2) Inbreeding can cause health problems as there is a higher chance of organisms inheriting harmful genetic defects when the gene pool is limited 3) Lower resistance to diseases - group vunerability -> less chance of resistant alleles being present

Answer 21

growing cells on an artificial growth medium -> Whole plants can be grown

Answer 22

- Made quickly and in all seasons - Plants produced are genetically identical organisms (clones) - can produce plants witht th same beneficial features

Answer 23

1) Pick the plant you want to clone (based of characteristics) 2) Remove several small peices of tissue from the parent plant - best results from fast-growing root or shoot tips 3) Grow the tissue in a growth medium containing nutrients and growth hormones -> Done under aseptic conditions to prevent growth of microbes that could harm the plants 4) As the tissues produce roots and shoots they can be transferred to potting compost to carry on growing

Answer 24

Medical Research - can carry out all sorts opf experiemnts on tissues in isolation

Answer 25

You can look at the effects of a particular substance or environmental change on the cells of a single tissue, without complications from other processes in the whole organism

Answer 26

1) Take the sample of tissue you want to study (extracted from the animal) 2) The cells in the sample are seperated from eachother using enzymes 3) They are placed in a culture vessel and bathed in a growth medium containing all the nutrients that they need - allows them to grow and multiply 4) After several rounds of cell division, the cells can be split up again and placed into seperate vessels to encourage further growth | These are then stored for future use

Answer 27

Modifying an organisms' genome (DNA) to produce desireable characteristics -> involves the use of enzymes and vectors (carriers) | Enzymes can be used to cut up or join DNA

Answer 28

Recognise specific sequences of DNA and cut the DNA at these points - the peices of DNA are left with sticky ends where they have been cut

Answer 29

used to join 2 pieces of DNA together at their sticky ends

Answer 30

2 peices of DNA stuck together

Answer 31

**A vector is something that is used to transfer DNA into a cell** - Plasmids and Viruses

Answer 32

Small, Circular molecules of DNA that can be transferred between bacteria

Answer 33

They insert DNA into the organisms they infect

Answer 34

1) The **DNA you want to insert** (e.g. the gene for human insulin) and the **vector DNA** is **cut out/(vector opened)with a restriction enzyme** 2) The Vector DNA and DNA you're inserting are left with sticky ends and then mixed together with ligase enzymes 3) The Ligases join the peices of DNA together to make **recombinant DNA** 4) The recombinant DNA (i.e. the vector containing new DNA) is inserted into other cells, e.g. bacteria 5) These cells now can use the gene you inserted to make the protien you want

Answer 35

Bacteria containing the gene for human insulin can be grown in huge numbers in a fermenter to produce insulin for people with diabetes

Answer 36

Crops can be genetically modified to be resistant to herbicides ( chemicals that kill plants). - Means farmers can spray their crops to kill weeds, without harming the crop itself - increasing yield

Answer 37

Researchers have managed to transfer human genes that produce useful proteins into sheep and cows. *E.g. human antibodies used in therapy for illnesss like arthiritis, some types of cancer, and multiple sclerosis* These protiens can then be extracted from the animal e.g. from their milk | Animals that have organs suitible for human transplant - made in future

Answer 38

1) hard to predict what effect modifying its genome will have on the organism - many genetically modified embryos don't survive and some genetically modified animals suffer from health problems later in life

Answer 39

1) Transplanted genes may get out into environment - e.g. a herbicide resistance may be picked up by weeds, creating a new "superweed" variety 2) Could adversely affect food chains - or even human health

Answer 40

**Genetically modified organisms** - Used to help provide food for many people in the world that suffer from hunger

Answer 41

To make them resistant to insect pests - improve crop yields and reduce need for chemical pesticides -> E.g. a bacterium called Bacillus thuringiensis (Bt) which produces a toxin which kills many of the insect larvae that are harmful to crops | or could help resistance to droughts

Answer 42

The gene for the Bt toxin is inserted into crops, such as corn and cotton, which then produce the toxin in their leaves and stems - making them less resistant to insect pests ( the toxin is specific to insects so will not harm other organisms)

Answer 43

The insects that feed on the crops are constantly exposed to the toxin, so there's a danger they will develop a resistance and no longer be killed by it. - farmers use a variety of insecticides to try and stop this from occuring | Also the long term effects of exposure to Bt are unknown

Answer 44

The population is rising rapidly - we all need access to enough food that is safe for us to eat and has the right balance of nutrition - Called "food security"

Answer 45

Golden rice has been genetically engineered to produce a chemical thats converted in the body into vitamin A

Answer 46

1) Many argue that people go hungry because they cannot afford food, not because there isnt enough, so they think they should combat poverty first 2) There are fears that countries will be reliant on others that sell GM seeds 3) Sometimes poor soil is the reason why crops fail, and even GM crops wont survive

Answer 47

Fertilisers or Biological control

Answer 48

Fertilisers contain minerals essential for plant growth - replenish poor soil (replace ions lost to previous crops)

Answer 49

Eutrophication in rivers and lakes

Answer 50

Using other organisms (i.e. predators and paracites) to reduce pest numbers

Answer 51

Cane toads were introduced in Australia to eat beatles that were damaging crops

Answer 52

Longer-lasting effects than chemical pesticides and can be less harmful to wildlife

Answer 53

Introducing new organisms can cause problems - e.g. Cane toads are now a pest themselves in Australia as they poison the native species that eat them

Answer 54

1) Structural features - Simpler = older 2) Using stratigraphy 3) Stone tools are often found with carbon-containging material e.g. a wooden handle - carbon-14 dating can be used to date this material

Answer 55

The study of rock layers - Older rocks are normally found below younger layers = tools or fossils in deeper layers are usually younger

Answer 56

A limb with 5 digits