SB4- Natural Selection And Genetic Modification

Question 1

What’s a binomial system

Answer 1

Using 2 Latin words for naming a species

Question 2

What’s evolution

Answer 2

The gradual change in the characteristics in a species over time

Question 3

Tell me about Ardi

(Ardipithecus ramidus)

Discovered 1992

Answer 3

Estimated 4.4 million years old

About 1.2m tall and 50kg

Leg bones show she could walk upright

Very long arms, very long big toes that stuck out to sides so she could climb trees

Question 4

Tell me about Lucy

Australopithecus afarensis

Discovered 1974

Answer 4

Lived about 3.2 million years ago (3.9 to 3.0 for while species)and about 1.07m tall

Probably could walk upright, toes arranged like modern humans buy much more curved

Question 5

Tell me about Homo habilis

2.4 - 1.4 million years ago

Discovered in 1960s

Answer 5

Quite short with long arms but walked up right

Question 6

Tell me about homo Erectus

Discover in late 19th century

Answer 6

Tall, 1.79m tall and strongly built, found in Asia- according to a 1.6 million year old skeleton

Lived 1.8 to 0.5 million years ago

We are Homo sapiens (195,000 years to present)

Question 7

When does the earliest evidence of human like animals using stone tools date back to

Answer 7

3.3 million years ago

Question 8

How can we find the ages of stone tools

Answer 8

Work out different ages of rock then assume that as stone tool is about the same age as the layer of rock it’s found

Question 9

How have stone tools changed

Answer 9

Oldest ones are very simple only used for skinning an animal or cutting up meet

Tools found in more recent rocks are more sophisticated

Question 10

What were some problems with why Darwins theory of natural selection were not accepted

Answer 10

We could still not explain how variation occurred and the evolution of characteristics in fossils was not gradual (actually it was but appeared there were jumps due to lack of fossils discovered

Question 11

What’s the pentadactyl limb

Answer 11

The fact that vertebrates have limbs with 5 fingers

Suggest we all have devolved from a common ancestor, over millions of year natural selection has caused bones in the pentadactyl limb to fuse together and change shape

Question 12

What’s natural selection

Answer 12

When those that are better adapted or suited to their environment would survive and reproduce and pass on their characteristics

Question 13

What’s classification according to Linnaeus

Answer 13

Dividing organisms into groups based on what they look like

Question 14

What were the largest groups in classification used by Linnaeus

Answer 14

The kingdoms were plants and animals

The groups were divided into smaller and smaller groups, the characteristics of the organisms in a group get more and more similar as the groups get smaller

The last group contained one type of
Organism, he used the 2 last groups (genus and species) to give each organism a binomial name)

Question 15

What are the problems with using characteristics for classification

Answer 15

For organisms that have evolved characteristics but not closely related

Question 16

What are the kingdoms we use today

Answer 16

Animals

Plants

Fungi

Protists

Prokaryotes

Base them on what the CELLS look like

Question 17

Tell me about the animal kingdom

Answer 17

Multicellular

Cells have nuclei but no cell walls

Question 18

Tell me about the plant kingdom

Answer 18

Multicellular

Cells have chloroplasts

Cells have nuclei

Have cellulose cell walls

Question 19

Tell me about the fungi kingdom

Answer 19

Multicellular apart fro yeasts

Live in or on dead matter

Cells have nuclei

Some have cells walls made of different substances but not chitin

Question 20

Tell me about prokaryotes

Answer 20

Unicellular

Cells do not have nuclei, flexible cell walls

Question 21

What are the 3 domains, all organisms are divided into these

Answer 21

Archaea - cells with no nucleus, genes contain unused sections of DNA

bacteria - cells with no nucleus, no unused sections in genes

Eukarya - cells with a nucleus, unused sections in genes (5 kingdoms)

Question 22

How can we work out how close 2 organisms are related

Answer 22

The more DNA 2 organisms have in common, the more recently they have evolved from a common ancestor and the more closely related they are

Question 23

What’s artificial selection

Answer 23

When humans choose certain organisms Becuase they have useful characteristics

Such as sheep with thick wool

Question 24

What’s selective breeding

Answer 24

Choosing animals or plants with useful characteristics to breed and produce new breeds of animal species and new varieties of plant species

Question 25

Why are plants and animals often selectively bred

Answer 25

Disease resistance - how well they cope with disease

Yield- how much useful product they make

Coping with certain environmental conditions

Fast growth

Flavour

Question 26

What is genetic engineering

Answer 26

Involves changing the DNA of an organism (it’s genome) often by inserting genes from another

Creates genetically modified organism (GMO’s)

Process is much faster than artificial selection but much more expensive

Question 27

Tell me about golden rice

Answer 27

It’s a GMO with 2 genes inserted into its genome, one from a daffodil and one from a bacterium

They allow rice to produce BETA-CAROTENE in its grains, beta carotene allows humans to make vitamin A - a lack of which can cause blindness

Question 28

What GMO animals are being developed

Answer 28

GM goats and sheep to produce proteins in their milk that can treat human diseases

GM pigs are being developed with human like organs to use in organ transplants

Question 29

What are some uses of GM bacteria

Answer 29

They make a range of useful substances, including antibiotics and other medicines

Question 30

What is tissue culture

Answer 30

The growing of cells or tissues in a liquid containing nutrients or on a solid medium such as nutrient agar

This is a useful way to grow many identical cells - this may form a callus (clump of undifferentiated cells)

Sometimes the cells are then treated to make them differentiate

Question 31

How can tissue culture help extinction

Answer 31

It is used to produce new individuals of a plant species that may be difficult to grow from seed - this technique is also used to produce clones of GM plants

Question 32

Why must everything be sterile

Answer 32

In tissue culture everything must be sterile to prevent growth of microorganisms

Question 33

Tell me how a plant tissue culture works - the callus method

Answer 33

A Piece of plant is placed in bleach solution to sterilise it

Then there are 2 routes

The first, then sometimes only a few cells are cut off and placed on sterile nutrient medium to grow into a callus

The callus is treated with hormones so the plantlets develop with roots and shoots

The plantlets are separated and grown on nutrient medium in sterile conditions

When the plants are large enough, they are planted into soil or compost

Question 34

Tell me how a plant tissue culture works - cuttings method

Answer 34

A piece of plant is placed in bleach solution to sterilise it

Sometimes a small piece of plant is cut off and placed on sterile nutrient medium to grow

The piece of plant is treated with hormones so it grows roots and shoots

When the plants are large enough
, they are planted into soil or compost

Question 35

What else can tissue cultures be used for

Answer 35

Used in medicine

Used to study viruses

Cultures of cancer cells developed to show how they develop and spread - using cell cultures allows scientists to investigate how infected cells respond to new medicines without risking harm to animals or humans

Cultures of human cells can be developed into tissues if correctly supported

Question 36

What’s selective breeding

Answer 36

Selecting certain alleles to breed to make a characteristic

Question 37

How is farming huge numbers of a huge breed also a problem

Answer 37

All the organisms are similar so if a change in environment affects one organism - all the others are affected

Animal welfare eg chickens produce so much breast they can barely stand up

Question 38

What are some GM issues

Answer 38

The GM seeds are expensive

Some think that GM crops will reproduce with wild plant varieties and pass on their herbicide and pesticide resistance to wild plants and weeds

Others think GM organisms may be bad for health - no evidence to support this

Question 39

Tell me about insulin

Answer 39

It treats type 1 diabetes

Insulin is usually extracted from dead bugs and cows

Buy GM bacteria can produce insulin and it’s cheaper and suitable for vegans or those who do not eat pork or beef due to religious reasons

Question 40

Tell me about the genetic engineering of bacteria

Answer 40

The plasmid of a bacteria has genes added, the plasmid of DNA combined in a new and so it’s an example of recombinant DNA

Scientists use restriction enzymes to cut a useful gene out of an organisms DNA - this cutting leaves sticky ends - they can be joined together using a ligand enzyme

Any DNA molecule used to carry new DNA Into another cell is called a vector

Question 41

Tell me the process of genetically engineering bacteria to produce insulin

Answer 41

A restriction enzyme is used to cut insulin gene from a human chromosome, this makes sticky ends (unpaired bases)

The restriction enzyme also cuts plasmids open - creating sticky ends again

The sections of DNA containing insulin gene are mixed with cut plasmids so complementary bases on sticky ends pair up

An enzyme called ligament is used to joins ends together

The plasmids are then inserted back into the bacteria which are then grown in huge tanks and so now the insulin can now be easily extracted

Question 42

How can insect pests be controlled from damaging a crops yield

Answer 42

Spraying the crop with insecticides - different ones kill different insects, many only affect the insect once they touch it

Question 43

What is Bt toxin

Answer 43

A soil bacterium Bacillus thuringiensis was discovered that makes a natural insecticide called the Bt toxin - crystals of it can be sprayed on to cells

The genes that control the productions of Bt toxin were introduced into plants so all cells in plants produced it

Question 44

What are some advantages of GM Bt toxin

Answer 44

It only affects insects that chew on the plant tissues - only released when cells are broken while insecticides make kill a range of insect species

Question 45

What’ are some disadvantage of GM Bt toxin

Answer 45

Insects that suck the sap from the crop such as aphids don’t chew on plant tissue and are not affected and so farmers may still need to spray crops to control other pests

Some insects could develop resistance to toxin - But there are many strains (varieties) of B. Thuringiensis bacteria to produce different forms of the toxin

Question 46

Tell me about prices of GM crop

Answer 46

Seeds are more expensive than non GM but farmers usually make more profit by growing GM varieties as long as people are willing to buy it

Question 47

What’s biological control

Answer 47

Using organisms to control pests or weeds

Question 48

Give me an example of biological control

Answer 48

St. John’s wort became a weed, it can cause illness in farm animals that eat it, instead of using herbicides Chrysolina beetles that prefer the weed to other plant species, were introduced and within ten years there was less than 1 percent of the original amount of weed left in California

Question 49

What is a fertiliser

Answer 49

A substance used to increase growth and yield of crop plants

Question 50

Tell me about fertilisers

Answer 50

They contain mineral ions such as nitrogen, potassium and phosphorus which allow a crop to grow well

Question 51

How can fertilisers lead to pollution

Answer 51

If not all is absorbed by a crop - some can get into a stream, river or lake and can lead to the death of organisms in the water or organisms that drink it