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

<p>Name the three key scientists who provided evidence for the theory of evolution.</p>

Answer 25

<p>Charles Lyell</p>

<p>Charles Darwin</p>

<p>Alfred Wallace</p>

Question 26

<p>What is classification?</p>

Answer 26

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

Question 27

<p>What is theLinnaean classification system?</p>

Answer 27

<ul> <li>Classification is the organisation of living things into groups according to their similarities in structure and characteristics</li> <li> <p>Closely related organisms are grouped together into groups called ‘taxa’</p> </li> <li> <p>Each taxa is arranged in a hierarchy, which divide into smaller more specific taxa.</p> </li> <li> <p>Kingdom - Phylum - Class - Order - Family - Genus - Species</p> </li></ul>

Question 28

<p>What is phylogeny and how has it advanced classification?</p>

Answer 28

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

Question 29

<p>What isthe 3-domain system?</p>

Answer 29

<ul> <li>Proposed by Carl Woese</li> <li>Classifies based upon chemical analysis -DNA, RNA and protein comparison to show phylogenic links</li> <li>Three domains: <ol> <li>Eukaryota – organism with complex subcellular structures (animals, plants, fungi, protist)</li> <li>Bacteria – true bacteria</li> <li>Archaea – primitive bacteria</li> </ol> </li></ul>

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Question 30

<p>What was artificial classification?</p>

Answer 30

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