B5.2 Natural Selection & Evolution

Question 1

<p>Evidence that shows change has taken place</p>

Answer 1

<ol> <li>Fossil record</li> <li>Rapid changes in species</li> <li>Genetics</li> <li>Extinction</li> <li>Molecular comparison</li></ol>

Question 2

<p>What does the evidence for fossils provide us?</p>

Answer 2

<p>A history of past life in earth.</p>

Question 3

<p>Why are fossils a significant source of evidence?</p>

Answer 3

<ul> <li>They showevolution within a species and evolution between one group of organisms</li> <li>They can help to build a comprehensive history</li> <li>They allow a picture to be built in terms of life upon Earth e.g. earliest fossils bacteria, then plants, then animal fossils.</li></ul>

Question 4

<p>How does fossil evidence show evolution has occurred?</p>

Answer 4

<ul> <li>Systematic change through time</li> <li>Different fossils found in different rock</li> <li>Oldest layers of rock show oldest fossils</li></ul>

Question 5

<p>What can be seen in the fossil record?</p>

Answer 5

<ul> <li>increase in complexity over time, simple organisms appeared first</li> <li>increase in diversity</li> <li>intermediate forms between groups - transitional fossils</li></ul>

Question 6

<p>What can not be seen in the fossil record?</p>

Answer 6

<ul> <li>Unable to show how life started on earth</li> <li>Earliest fossils were soft bodied, difficult to fossilise</li></ul>

Question 7

<p>Does evidence from fossils provide conclusive proof of change?</p>

Answer 7

<ul> <li>No. Record is biased/incomplete</li> <li>Very few individuals become fossils</li> <li>Hard-bodied organisms often form fossils</li> <li>Most fossils are aquatic animals</li></ul>

Question 8

<p>What are the main fossil types found?</p>

Answer 8

<ul> <li> <p><u>Impressions</u> are formed when footprints become covered in mud which hardens to rock.</p> </li> <li> <p><u>Moulds</u> are formed when a dead organism gets buried in mud, which hardens to rock.</p> </li> <li> <p><u>Caste fossil</u> can occur when mould fossils are filled with minerals that harden, taking the shape of the mould fossil</p> </li> <li> <p><u>Preserved fossils </u>occur when animals have been covered in a natural preservative such as ice, tar, amber or peat</p> </li></ul>

Question 9

<p>How does extinction provide evidence for evolution by natural selection?</p>

Answer 9

<p>Species which are not adapted to / do not have advantageous characteristics for their environment die out.</p>

Question 10

<p>State what is meant by the term fossil.</p>

Answer 10

<p>The remains of a plant or animal which have mineralised / changed to rock over millions of years</p>

Question 11

<p>State the most likely ancestor of all living things?</p>

Answer 11

<p>Unicellular aquatic organisms</p>

Question 12

<p>How do organisms evolve?</p>

Answer 12

<p>Through the process of natural selection.</p>

Question 13

<p>What is the process of evolution by natural selection?</p>

Answer 13

<ul> <li>Genetic variation is seen within species caused by differences in genes</li> <li>Organisms which have the most advantageous characteristics are the most likely to survive and reproduce</li> <li>Genes from successful organisms are passed to offspring</li> <li>This process is repeated many times and can lead to new species developing.</li></ul>

Question 14

<p>What is meant be the term 'survival of the fittest'?</p>

Answer 14

<p>Only the organisms which have the most advantageous characteristics are the most likely to survive.</p>

Question 15

<p>Why must scientist constantly develop new antibiotics?</p>

Answer 15

<p>Bacteria reproduce quickly, so any mutation which develops antibiotic resistance is quickly passed on to many offspring.</p>

Question 16

<p>State two examples of evolution that has happened in a short and observable time period?</p>

Answer 16

<ul> <li>The peppered moth changing from pale to dark due to the industrial revolution</li> <li>Bacteria evolvingresistanceto antibiotics</li> <li>Mosquitos evolving resistance to DDT</li> <li>Rats evolving resistance to the rat poison warfarin</li></ul>

Question 17

<p>During Darwin's infamous scientific expedition to the Galapagos Island, on which species did he make his famous observations?</p>

Answer 17

<p>Finches</p>

Question 18

<p>Who's hypothesis about the origins of fossils gave Darwin inspiration for the theory of evolution by natural selection?</p>

Answer 18

<p>Charles Lyell's</p>

Question 19

<p>What was the theory of spontaneous generation?</p>

Answer 19

<p>Appearance of animals from environments previouslydevoid of animals e.g. sudden appearance of fish in a puddle of water.</p>

Question 20

<p>State the key ideas ofJean-Baptiste Lamarck.</p>

Answer 20

<ul> <li>All organisms evolved through simple to more complex organisms</li> <li>Use vs. Disuse</li> <li>Organisms adaptduring their lifetime -altered their behaviour in response to environmental change, which modifies their organs.</li> <li>Acquired traits are heritable -whengiraffes stretch their necks to reach leaves high in trees, they would strengthen and gradually lengthen their necks. These giraffes would then have offspring with slightly longer necks.</li> <li>Continuous evolution towards ‘<em>perfection</em>’</li></ul>

Question 21

<p>This scientistindependently proposed the theory of evolution by natural selection while working in Borneo.</p>

Answer 21

<p>Alfred Wallace (1809-1882)</p>

Question 22

<p>What whereAlfred Wallace's key ideas?</p>

Answer 22

<ul> <li>Living things change over long periods of time</li> <li>Fittest individuals survived and reproduced</li> <li>Advantageous characteristics passed on to their offspring</li> <li>Speciation by reproductive isolation – Wallace effect</li></ul>

Question 23

<p>The study of which species led to Wallace's thinking?</p>

Answer 23

<p>Beetles and butterflies</p>

Question 24

<p>Why did the theory of evolution take time to be widely accepted?</p>

Answer 24

<ul> <li>At the time of publication, most people believed God created all animals and plants.</li> <li>Darwin’s theory was new / opposed this belief.</li> <li>Darwin was unable to explain how inheritance occurred</li> <li>Darwin had no knowledge of genes, which meant it was hard to convince people that the theory was correct.</li> <li>It took time to collect further evidence to support the theory.</li></ul>

Question 25

Name the three key scientists who provided evidence for the theory of evolution.

Answer 25

Charles Lyell

Charles Darwin

Alfred Wallace

Question 26

What is classification?

Answer 26

The organisation of living things into groups according to their similarities in genes, structure and characteristics

Question 27

What is the Linnaean classification system?

Answer 27

• Classification is the organisation of living things into groups according to their similarities in structure and characteristics

• Closely related organisms are grouped together into groups called ‘taxa’

• Each taxa is arranged in a hierarchy, which divide into smaller more specific taxa.

• Kingdom - Phylum - Class - Order - Family - Genus - Species

Question 28

What is phylogeny and how has it advanced classification?

Answer 28

• Study of evolutionary relationships with the aid of modern techniques such as DNA and protein analysis.
• It has led to the re-classification of some organisms
• It has led to the development of the 3-domain system and the new taxon 'domain'

Question 29

What is the 3-domain system?

Answer 29

• Proposed by Carl Woese
• Classifies based upon chemical analysis - DNA, RNA and protein comparison to show phylogenic links
• Three domains:
  1. Eukaryota – organism with complex subcellular structures (animals, plants, fungi, protist)
  2. Bacteria – true bacteria
  3. Archaea – primitive bacteria

 

Question 30

What was artificial classification?

Answer 30

• Grouping by observable characteristics not phylogeny
• Method led to inaccurate classification.
• Linnaeus’s method of classifying plants based on a limited number of their physical and sexual characteristics.