B15-Genetics and evolution

Question 1

What is a fossil?

Answer 1

The remains of a plant or animal from millions of years ago that have been preserved

Question 2

What are the 3 main ways fossils can form?

Answer 2

1-preserved traces(footprints/burrows/rootlet traces)
2-when parts of the organism doesn’t decay because one or more of the conditions for decay are absent
3-when parts of the organism are replaced by minerals as decay happens

Question 3

What are the criteria for decay to occur?

Answer 3

Oxygen, bacteria(decomposers), correct temperatures

Question 4

Why are fossils important?

Answer 4

To look at the anatomy of animals
How animals develop
All cells have a very similar chemistry-enzymes, DNA, ribsosomes etc.
Some organisms can be obseved evolving eg bacteria

Question 5

Name the person who first discovered inherited characteristics are determined by ‘units’ passed on unchanged

Answer 5

Gregor Mendel

Question 6

Why were Mendel’s ideas of inheritance not accepted during his time?

Answer 6

As chromosomes weren’t discovered

Question 7

Who published the double helix structure of DNA?

Answer 7

Watson and Crick

Question 8

Watson and Crick used whose work to find out the structure of DNA?

Answer 8

Franklin and Wilkins(but without Franklin’s permission)

Question 9

Name the person who proposed the theory of evolution

Answer 9

Charles Darwin

Question 10

Name the person who suggested changes that occur in an organism during its lifetime can be inherited

Answer 10

Jean-Baptiste Lamarck

Question 11

On what mechanism is Darwin’s theory of evolution based on?

Answer 11

Natural selection

Question 12

What is Darwin’s theory of evolution by natural selection?

Answer 12

All species have evolved from simple life forms

Question 13

State 3 reasons why Darwin’s ideas were only slowly accepted

Answer 13

1-conflict with the wild belief that God made all living things
2-insufficient evidence
3-no mechanism to explain variation and inheritance

Question 14

Who worked with Darwin to develop the theory of evolution?

Answer 14

Alfred Russel Wallace

Question 15

Apart from evolution what are 2 other studies Wallace worked on?

Answer 15

Warning colouration in animals+theory of speciation

Question 16

What is speciation?

Answer 16

The process by which 2 species evolve from a single original species by natural selection

Question 17

Give the 6 steps in the process of speciation(how does a new species arise)

Answer 17

1-geographical isolation(eg flood divides an island in 2)
2-different selection pressures/conditions in the new environments
3-genetic variation(bc of mutations) within the groups
4-best adapted individuals to the new conditions survive, reproduce and pass on these favourable alleles
5-no interbreeding over time, groups become more different to each other
6-after a large amount of time, unable to interbreed successfully-they’re now separate species

Question 18

Describe the 5 steps of fossilisation by mineralisation

Answer 18

1-organism dies and falls to the ground
2-flesh decays, leaving skeleton behind
3-bones are covered in sand/soil
4-bones become mineralised and turns into rock(fossil)
5-rock with fossil emerges due to geological movement(earthquake) and erosion occurs to reveal fossil

Question 19

Give 4 reasons why the fossil record is incomplete

Answer 19

1-many earliest life forms are soft-bodied
2-most organisms didn’t become fossilised
3-most early fossils were destroyed by geological activity
4-many fossils are not yet found

Question 20

How is the fossil record helpful?

Answer 20

Shows how much organisms have changed and developed over time and can show the environment and climate then

Question 21

Define extinction

Answer 21

Permanent loss of all members of a species

Question 22

State 3 causes of extinction

Answer 22

New predators, new diseases/pathogens, new successful competitors

Question 23

What causes mass extinction? Suggest 2 examples of this cause

Answer 23

Single catastrophic event that also affects climate over a long period(eg asteroid collision, volcanic eruption)

Question 24

Suggest a chain of events initiated by an asteroid collision that could lead to the extinction of dinosaurs

Answer 24

Asteroid impact causes huge fires and earthquakes–>volcanic eruptions–>dust/ash cloud covers atmosphere–>less sunlight reaches the Earth surface–>temp drop massively+plants die–>loss of food source led to other animals’ extinction

Question 25

What is antibiotic resistance?

Answer 25

Bacteria becoming resistant means it cant be killed by a certain antibiotic

Question 26

What causes antiobiotic resistance?

Answer 26

Random mutations in bacteria/bacteria sharing resistant genes

Question 27

Describe the steps in which a bacteria strain develops resistance to an antibiotic

Answer 27

1-mutation occurs in an individual bacterium within a population 2-it survives and reproduces rapidly, making more bacteria with its resistant gene 3-overtime all bacteria within the population have that gene

Question 28

Why can bacteria evolve quicker than other organisms?

Answer 28

Because bacteria can reproduce at a quick rate

Question 29

What is a genome?

Answer 29

The entire set of genes for an organism

Question 30

GIve 2 advantages of understanding the human genome

Answer 30

Identifying genes linked with inherited diseases , understanding human migration and evolution

Question 31

How 2 species of aniamls could have arisen from a common ancestor(speciation 6 marker)

Answer 31

Geographical separation; environmental differences, random mutation/variation, best adaptted in each aea survive breed and pass on allelses and genes, eventually the different populations can no longer succeessful breed with each other to produce fertile offspring

Question 32

Suggest 3 methods to prevent and slow down the development of antibiotic-resistant strains

Answer 32

1) Do not overuse antibiotics 2)patients finish anitbiotic course every time 3) restrict agricultural use of antibiotics

Question 33

Why must patients finish their course of antibiotics every time?

Answer 33

To ensure all bacteria are killed by the antibiotic so none can survive to mutate and develop resistance

Question 34

Suggest 3 ways in which a hospital can reduce the spread of antibiotic-resistant strains

Answer 34

Only use antibiotics if really needed, use strain-specific antibiotics, maintain high hygiene standards(wash hands between patient visits), isolate patients infected with resistant strain, vistors wash hands as they enter and leave

Question 35

Why is it difficult to develop new antibiotics to combat the appearance of new antibiotic-resistant strains of bacteria?

Answer 35

The development of new antibiotics is expensive and slow(won't be able to keep up)

Question 36

What does classification of organisms mean?

Answer 36

Organisation of living things into groups based on thier similarities

Question 37

Name the person who developed the classification system

Answer 37

Carl Linnaeus

Question 38

State the 7 hierachical levels of the Linnaean classification system

Answer 38

Kingdom, phylum, class, order, family, genus, species

Question 39

Every organism has a scientific name using a binomial system-what does binomial mean?

Answer 39

2 names

Question 40

Which language does the binomial naming system use?

Answer 40

Latin

Question 41

The binomial name of an organism is made up of 2 words-what does each word represent of that organism?

Answer 41

The 1st word is the genus; 2nd word is the species

Question 42

What are the 3 rules of writing a binomial scientific name of species?

Answer 42

1st letter of the genus should be in capital; 1st letter of the species should be in lower case letter; both need to be in italics when printed or underlined when hand-written

Question 43

Why do we use the binomial naming system?

Answer 43

Every organisms' names would vary in different language, but Latin is considered to be the old common language in which everyone can use/understand

Question 44

How many domains and kingdoms do scientists now consider in classifications?

Answer 44

3 domains, 6 kingdoms

Question 45

Based on what knowledge were the 3 domains set?

Answer 45

Different biochemistry of cell and ribosomes, and how cells reproduce differently

Question 46

What are the 3 domains?

Answer 46

Archaea, bacteria, eukaryota

Question 47

What are the 6 kingdoms?

Answer 47

Archaebacteria, eubacteria, protista, fungi, plants, animals

Question 48

How is classification helpful?

Answer 48

Helps us to understand evolutionary and ecological relationships, makes them easier to study, helps us recognise biodiversity and gives scientists a common language in which to talk about it

Question 49

Name the type of models that are used to show how different organisms are related

Answer 49

Evolutionary trees

Question 50

What aspects of knowledge would be considered when suggesting evolutionary relationships?

Answer 50

Similarities and differences in physical structures, genetics and biochemistry