Topic 4 - Natural Selection 10

Question 1

Humans evolution

Answer 1

• Evolution is the gradual change in the
  characteristics of a species over time.
• Scientists believe that modern humans
  (Homo sapiens) evolved from apes.

Question 2

Fossils

Answer 2

Fossils are the
‘remains’ of organisms
from thousands or
millions of years ago, which are found in rocks.

Question 3

Fossils - the evidence of evolution

Answer 3

• Fossils of the simplest
  organisms are found in
  the oldest rocks, and
  fossils of more complex
  organisms in the newest
  rocks.
• This supports the
  theory of evolution,
  which states that simple
  life forms gradually
  evolved into more
  complex ones.

Question 4

How do fossils useful

Answer 4

Shows us characteristics
of this organism and
gives an estimate of
when it lived.

Question 5

What other evidence
might be useful to help
us understand it’s place
in evolution?

Answer 5

Compare to living
organisms and other
fossils to look for
similarities and
differences.

Question 6

4 key points about Natural selection

Answer 6

1. Individuals within a species show variation.
2. Individuals within a compete for resources.
3. Only the individuals best adapted to the environment will survive.
4. Only the survivors will pass on their genes.

Question 7

What is Darwin’s theory of evolution by natural selection

Answer 7

Organisms that are best adapted for their environments will reproduce and pass on their acquired characteristics.

Question 8

Variation

Answer 8

Variation: The differences in characteristics between individuals within a population.

Question 9

Survival of the Fittest

Answer 9

Survival of the Fittest: A concept in natural selection that suggests that individuals with traits best suited to their environment are more likely to survive and reproduce.

Question 10

Natural Selection

Answer 10

Natural Selection: The process by which organisms better adapted to their environment tend to survive and produce more offspring.

Question 11

Evolution

Answer 11

Evolution: The gradual change in the characteristics of a species over generations, driven by natural selection.

Question 12

Antibiotic Resistance

Answer 12

Antibiotic Resistance: The ability of bacteria to survive and multiply despite the presence of antibiotics that were intended to kill or inhibit them.

Question 13

Classification

Answer 13

Classification is the grouping of organisms based on similarities of features.

Question 14

What is artificial classification?

Answer 14

Based on observable features.
For example: beak shape, flower colour, number legs.

Question 15

What is natural classification?

Answer 15

a scientific classification according to features which are held to be objectively significant, rather than being selected for convenience.

Question 16

Why do we classify organisms?

Answer 16

• Our convenience.
• To make to study of organisms more manageable.
• To make it easy to identify organisms.
• To help see relation dbetween organisms.

Question 17

Who developed the first classification system, 250 years ago?

Answer 17

Carl Linnaeus started it all of 250 years ago using visible features of organisms - limited

Question 18

What is taxon?

Answer 18

Each unit is called taxon there are 7 of them.
K, P, C, K, O, F, G, S

Question 19

Taxon, Cat,Leopard, man,
K:

Answer 19

Cat,Leopard,Man: Animalia.

Question 20

Taxon, Cat,Leopard, man,
P:

Answer 20

Cat,Leopard,Man: Chordata.

Question 21

Taxon, Cat,Leopard, man,
C:

Answer 21

Cat,Leopard,Man: Mammalia.

Question 22

Taxon, Cat,Leopard, man,
O:

Answer 22

Cat: Carnivora.
Leopard: Primates.
Man: Primates

Question 23

Taxon, Cat,Leopard, man,
F:

Answer 23

Cats: Felidae.
Leopard: Felidae.
Man: Anthropoids( apes ).

Question 24

Taxon, Cat,Leopard, man,
G:

Answer 24

Cats: Felis.
Leopard: Panthera.
Man: Homo.

Question 25

Taxon, Cat,Leopard, man,
S:

Answer 25

Cats: Cattus.
Leopard: Panthera - pardus.
Man: Sapiens.

Question 26

What is selective breeding?

Answer 26

Breeding the animals with a desired feature together to ensure the offspring have the desired feature.

Question 27

Different breeds of sheep

Answer 27

Are used for wool, meat or milk.
We have selected the traits to increase the value in humans.

Question 28

Plants and animals are often selectively bred for:

Answer 28

Disease resistance ( how well they cope with disease ), Yield ( how much useful product they make ), coping with certain environmental conditions, fast growth, flavour.

Question 29

Genetic engineering

Answer 29

Genetic engineering involves changing in the DNA of one organism ( it is genome ), often by increasing genes from another. This creates genetically modified organisms (GMOs). The process is much faster then artificial select but much more expensive.

Question 30

Genetic engineering, example Golden Rice:

Answer 30

• genetically modified organism (GMO).
• 2 genes inserted into its genome, from 1 a daffodil and 1 from bacterium.
• they allows rice to produce beta carotene ( which allows humans to mane a vitamin A).
• helps prevent blindness.

Question 31

Name 4 issues with genetic engineering:

Answer 31

• seeps for GM crops are expensive.
• potential reproduction with wild plant varieties - pass on resistant genes which may have unknown consequences?
• health issues eating GM crops.
• medicines made by GM bacteria may not work as well.

Question 31

Describe the process by which a gene is inserted into a bacteria:

Answer 31

1. Restriction enzymes make staggered cuts in DNA molecules, producing sections with a few unpaired bases at each end -‘sticky ends’ . A section of DNA containing the gene for making insulin is cut from a human chromosome in this way.
2. Restriction enzymes are also used to cut plasmids open. By using the same restriction enzyme as was used on the human chromosome in this way.
3. Selections of DNA containing the insulin gene are mixed with the cut plasmids. The complementary bases on the sticky ends pair up. An enzyme called ligase is used to join the ends together.
4. The plasmids are then inserted back into bacteria, which are then grown in huge tanks. The insulin they now make can easily be extracted.

Question 32

Benefits of genetic modified organisms ( GMO):

Answer 32

• can make organisms resistant to disease, grow faster and larger the normal.
• GM sheep and goats that produce protein in their milk to treat diseases.
• GM pigs being developed with human-like organs for transplants.

Question 33

Issues with genetic engineering

Answer 33

• seeds for GM crops are expensive.
  Potential reproduction with wild plant varieties => pass on resistant genes which may have unknown consequences?
• health issues eating GM crops.
• medicines made by GM bacteria may not work as well.

Question 34

Example - genetic engineering of bacteria

Answer 34

A bacterium has one large loop of DNA and some small circles of DNA called plasmids.