Natural Selection And Genetic Modification

Question 1

What does natural selection mean

Answer 1

Survival of the fittest

Question 2

What are selection pressures

Answer 2

Things that affect an organisms chance of surviving and reproducing

Question 3

What are examples of selection pressures

Answer 3

Predation, competition for resources, disease

Question 4

Why does antibiotic resistant bacteria support Darwin’s theory of evolution

Answer 4

It makes the bacteria better adapted to an environment in which antibiotics are present, as a result antibiotic resistance becomes more common in the population over time

Question 5

What is Darwin’s theory of evolution by natural selection

Answer 5

If an organism develops a mutation in their dna it creates new alleles which change their characteristics, some of which can be big advantages such as bacteria being resistant to antibiotics, this organism is then better suited and adapted to the environment and better able to survive and so lives longer and reproduces passing on the specific allele for that characteristic advantage

Question 6

What is a fossil

Answer 6

Any trace of an animal or plant that lived a long time ago

Question 7

How do fossils provide evidence for evolution

Answer 7

It shows how species have changed and developed over billions of years

Question 8

What are hominids

Answer 8

Human beings and their ancestors

Question 9

What is an ardi and how old is she

Answer 9

A fossil of the species ardipithecus ramidus, 4.4 million years old

Question 10

What characteristics does an ardi have

Answer 10

Ape-like big toe-climbed trees, long arms, short legs, brain size of a chimpanzees, walked upright and didn’t use her hands to walk

Question 11

What is a Lucy and how old is she

Answer 11

Fossil of the species Australopithecus afarensis, 3.2 million years old

Question 12

What features does a Lucy have

Answer 12

Arched feet more adapted to walking than climbing, arms and legs same size and apes and humans, brain slightly larger than an ardi but similar to chimp, walked upright-more efficiently that ardi

Question 13

What did Richard Leakey organise

Answer 13

An expedition to Kenya to look for hominid fossils

Question 14

What did Leakey find, what species was it and how old was it

Answer 14

Turkana boy, homo erectus, 1.6 million years old

Question 15

Features of the Turkana boy fossil

Answer 15

Short arms and long legs-human like, brain size-larger than Lucy’s-human like, even better adapted to walking upright than Lucy

Question 16

What stone tool did the homo habilis use

Answer 16

More simple tools called pebble tools, by hitting rocks together to make sharp flakes - used to scrape meat from bones or crack bones open

Question 17

What stone tools did homo erectus use

Answer 17

Sculpted rocks into shapes to produce more complex tools like simple hand-axes - used to hunt, dig, chop and scrape meat from bones

Question 18

What stone tools did the home Neanderthalensis use

Answer 18

More complex tools, evidence of flint tools, pointed tools and wooden spears

Question 19

What tools did Homo sapiens use

Answer 19

Flint tools, pointed tools-arrowheads, fish hooks, needles appeared around 50,000 years ago

Question 20

How old were homo habilis

Answer 20

2.5-1.5 million years ago

Question 21

How old where the homo erectus species

Answer 21

2-0.3 million years ago

Question 22

How old were the homo neanderthalensis

Answer 22

300,000-25,00 years ago

Question 23

How old were the Homo sapiens

Answer 23

200,000 years ago

Question 24

What are the 3 different ways scientists can work out how old a fossil tool is

Answer 24

Looking at the structural features(simpler tools=older), using stratigraphy -study of rock layers(older rock layers found under younger rock)-stones and tools found deeper in rock=older, carbon-14 dating can be used to date stone tools as they often contain carbon-containing material

Question 25

What is classification

Answer 25

Organising living organisms into groups

Question 26

How are organisms classified

Answer 26

On their characteristics, as technology improved, included things u can see with a microscope

Question 27

What’s the system called to classify organisms

Answer 27

The five kingdom classification system

Question 28

What are the 5 kingdoms

Answer 28

Animals, plants, fungi(mushrooms,yeasts,toadstools), prokaryotes, protists(eukaryotes)

Question 29

What are the 5 kingdoms then subdivided into

Answer 29

Phylum, Class, order, family, genus, species

Question 30

Who invented the three domain system

Answer 30

Carl Woese

Question 31

What are the 3 domains

Answer 31

Archaea, bacteria, eukarya

Question 32

Why was the 3 domain system introduced

Answer 32

Technology had developed further and our understanding about biochemical processes and genetics improved, we can now determine the sequence of DNA bases in organisms genes and compare them - more similar = more closely related

Question 33

What is selective breeding

Answer 33

When humans artificially select the plants or animals that are going to breed so the genes for particular characteristics remain in the population

Question 34

What are some disadvantages of selective breeding

Answer 34

Reduces the gene pool(no. Of different alleles in a population), inbreeding can cause health issues(more chance of the organism inheriting harmful genetic defects when the gene pool is limited), can be serious problems of a new disease appears(not much variation in the population so not many disease resistant organisms-all organisms are closely related to if 1 organism dies from a disease the rest are likely too)

Question 35

What do restriction enzymes do

Answer 35

Recognise specific sequences of dna and cut the dna at these points - the pieces of dna are left with stick ends where they have been cut

Question 36

What are ligase enzymes

Answer 36

Used to join 2 pieces of dna together at their sticky ends

Question 37

What is recombinant dna

Answer 37

2 different bits of dna stuck together

Question 38

What is a vector

Answer 38

Something that’s used to transfer dna into a cell

Question 39

What are the 2 sorts of vectors

Answer 39

Plasmids, viruses

Question 40

What are plasmids

Answer 40

Small, circular molecule of dna that can be transferred between bacteria

Question 41

What do viruses do

Answer 41

Insert dna into the organisms they infect

Question 42

What are the steps of genetic engineering

Answer 42

1) the dna u want to insert is cut out with restriction enzymes, the vector dna is then cut open using the same restriction enzyme 2) the vector dna and the dna you’re inserting are left with sticky ends. They are mixed together with ligase enzymes 3) ligases join the pieces of dna together to make recombinant dna 4) the recombinant dna is inserted into other cells 5) these cells can now use the gene u inserted to make the protein u want

Question 43

Why is genetic engineering useful in agriculture

Answer 43

Crops can be genetically modified to be resistant to herbicides

Question 44

Why is genetic engineering useful in medicine

Answer 44

Genetically engineered bacteria can produce insulin, human genes can be transferred into animals to produce useful proteins

Question 45

What is the disadvantage of genetic engineering of animals

Answer 45

It’s hard to predict what effect modifying its genome will have on the organism

Question 46

What is the concern of genetically modified crops

Answer 46

The transplanted genes may get out into the environment and may make weeds herbicide resistant, they could affect food chains or human health

Question 47

What is genetic engineering

Answer 47

A process which involves modifying the genome of an organism to introduce desirable characteristics

Question 48

What are the advantages of selective breeding for agriculture

Answer 48

Genetic variation means some cattle will have better characteristics and produce more meat

Question 49

Why is selective breeding used in medical research

Answer 49

Using rats can investigate the reason behind alcoholism, rats with strain and weak preferences for alcohol are bred to compare the differences between the 2 different types of rats and the way their brains work