B14 & 15 - Evolution

Question 1

What factors cause variation within a species?

Answer 1

• Genes they have inherited
• Environmental factors
• A combination of both

Question 2

What leads to genetic variants?

Answer 2

Mutations

Question 3

What is the theory of natural selection?

Answer 3

That all species of living things have evolved from simple life forms that first developed more that 3 billion years ago

Question 4

How does natural selection happen?

Answer 4

• There is variation between organisms
• The best adapted have an advantage
• These organisms are more likely to survive and reproduce
• They pass on useful alleles onto offspring
• The useful characteristic is more common in the population

Question 5

How does selective breeding happen?

Answer 5

• Parents with the desired characteristic(s) are chosen
• They are bred together
• From the offspring those with the desired characteristic(s) are bred together
• This continues over many generations

Question 6

What kind of characteristics are selectively bred?

Answer 6

• Disease resistance in crops
• Greater meat or milk production in animals
• Gentle nature in pets
• Large or unusual flowers

Question 7

What is inbreeding?

Answer 7

When too much selective breeding happens and some breeds are particularly prone to disease or inherited defects

Question 8

What is genetic engineering?

Answer 8

The modification of the genome of an organism by introducing a gene from another organism to give a desired characteristic

Question 9

Why make GM crops?

Answer 9

• Resistant to insects or herbicides
• Larger fruit
• Increased yields

Question 10

What are some concerns about GM crops?

Answer 10

• Effects on populations of wild flowers and insects
• Effects on humans who eat them aren’t fully known

Question 11

How have bacterial cells been genetically engineered?

Answer 11

They produce useful substances e.g. human insulin

Question 12

What are the stages of genetic engineering?

Answer 12

• Enzymes isolate the required gene
• Gene is inserted into a vector e.g. bacterial plasmid or virus
• Vector is used to insert the gene into the required cells
• Genes are transferred into cells of the organism in early stages of development

Question 13

How would you clone a plant?

Answer 13

• Tissue culture
• Cuttings

Question 14

How does tissue culture cloning work?

Answer 14

Using small groups of cells to grow new, identical plants

Question 15

How does cloning through cuttings work?

Answer 15

Cut the plant and repot a bit of it

Question 17

Why would you clone a plant?

Answer 17

• Preserving rare species
• Commercially in nurseries

Question 18

How would you clone an animal?

Answer 18

• Embryo transplants
• Adult cell cloning

Question 19

How does an embryo transplant work?

Answer 19

• Split apart cells from a developing embryo before they specialise
• Transplant the identical embryos into host mothers

Question 20

How does adult cell cloning work?

Answer 20

• The nucleus is removed from an unfertilised egg
• The nucleus from a body cell is inserted into the hollow egg
• Use an electrical shock to stimulate the egg into dividing
• An embryo with the new DNA is formed
• The embryo is inserted into a uterus to continue it’s development

Question 21

What did Mendel do?

Answer 21

• Experimented on pea plants
• Theorised “hereditary units” - (Genes)
• Characteristics were received from parents
• Dominant and recessive

Question 22

Why was Mendel not appreciated until after death?

Answer 22

• He didn’t publish his work
• People didn’t know about genes, DNA ect.

Question 23

When was chromosome behaviour during cell division observed?

Answer 23

Late 19th century

Question 24

When was DNA’s structure found?

Answer 24

Mid-20th century

Question 25

What did Darwin do?

Answer 25

- Natural selection - On the Origin of Species

Question 26

Why wasn't natural selection accepted?

Answer 26

- God made everything - Not enough evidence - Genes ect. weren't discovered for 50 years

Question 27

What did Lamarck think?

Answer 27

Changes that occur during the lifetime of an organism can be inherited

Question 28

Why has natural selection been accepted?

Answer 28

- Genes have been understood - Evidence from the fossil record - Antibiotic resistance

Question 29

What is speciation?

Answer 29

When two populations become so different in phenotype that they don't breed to have fertile offspring

Question 30

How is a new species made?

Answer 30

- Geographical isolation - Environmental differences - Genetic variation - Natural selection - Speciation

Question 31

What did Wallace?

Answer 31

- Natural selection (+ Darwin) - Speciation

Question 32

What is a fossil?

Answer 32

- The remains of organisms from millions of year ago, found in rocks

Question 33

How are fossils formed?

Answer 33

- Parts of organisms that have not decayed are buried in sediments - Parts of the organism are replaced by minerals

Question 34

Why can scientists not be certain how life on earth began?

Answer 34

- Early life was soft-bodied so have left few traces - Traces have been destroyed by volcanic activity

Question 35

What is extinction?

Answer 35

When no individuals of a species are alive

Question 36

Why do bacteria evolve rapidly?

Answer 36

They reproduce at a fast rate

Question 37

How do bacteria become resistant to antibiotics?

Answer 37

Natural selection: - Mutations create new strains - Some strains will be resistant so aren't killed - They survive and reproduce more with less competition - The resistant strain spreads because there's no treatment

Question 38

Name an antibiotic resistant bacteria

Answer 38

MRSA

Question 39

How can antibiotic resistance be reduced?

Answer 39

- Only take antibiotics when necessary - Complete the course - Reduce use of antibiotics agriculturally

Question 40

Why is antibiotic resistance a worry?

Answer 40

New antibiotics are slow and costly to develop

Question 41

What did Linnaeus do?

Answer 41

Classification

Question 42

What is the classification system?

Answer 42

Kingdom, Phylum, Class, Order, Family, Genus, Species

Question 43

What is used in the binomial system?

Answer 43

Genus and species e.g. Orcinus orca

Question 44

What did Woese do?

Answer 44

Three domain system

Question 45

What are the three domains?

Answer 45

Archaea - Primitive bacteria Bacteria - True bacteria Eukaryota - Protists, fungi, plants and animals