Evolution and natural selection

Question 1

What is evolution?

Answer 1

The theory that describes the way in which organisms evolve, or change, over many years as a result of natural selection

Question 2

What did Darwin realise?

Answer 2

Organisms best suited to their environment are more likely to survive an reproduce

Question 3

What is the result of evolution?

Answer 3

Species change over time to have a more advantageous phenotype for the environment which it lives in

Question 4

What are scientists that influenced Darwin?

Answer 4

Lyell, Hutton and Wallace

Question 5

How did Lyell influence Darwin?

Answer 5

He suggested fossils were actually evidence of animals who lived millions of years ago

Question 6

How did Hutton influence Darwin?

Answer 6

Proposed the concept of uniformitarianism, which prompted Darwin to think evolution was a process of small changes over time

Question 7

What is uniformitarianism?

Answer 7

The idea that in the past, the earth was shaped by forces you can still see, such as sedimentation in rivers, wind erosion and deposition of ash and lava from volcanic eruptions

Question 8

What did Darwin observe about finches in the Galapagos?

Answer 8

They were similar in many ways so much be related, but beaks and claws were different shapes and sizes

Question 9

What did Darwin realise about his observations?

Answer 9

The design of beak was linked to food available on each island, so the bird with the ideal beak would survive longer and reproduce to pass on his beak

Question 10

What did Darwin publish with his findings?

Answer 10

The ‘origin of species’

Question 11

What happened as a result of Darwin’s publication?

Answer 11

It was very controversial, as evolution conflicted with the religious view that God created all animals and plans

Question 12

What do scientists use to study evolution?

Answer 12

Palaeontology, comparative anatomy and comparative biochemistry

Question 13

What are fossils?

Answer 13

Plant and animal remains preserved in rocks

Question 14

How do fossils form?

Answer 14

Sediment is deposited on earth to form layers (strata) of rock and different layers correspond to different geological eras

Question 15

What is the fossil record?

Answer 15

Fossils are different and form a sequence from oldest to youngest within strata, showing how organisms change over time

Question 16

What is palaeontology?

Answer 16

The study of fossils

Question 17

What is the result of palaeontology?

Answer 17

Gives us evolutionary relationships and approximate timings of when species rose

Question 18

What is an issue with the fossil record?

Answer 18

It is incomplete

Question 19

Why is the fossil record incomplete?

Answer 19

Soft bodied organisms decay rapidly, conditions for fossils to form aren’t always present, can be destroyed by earth’s forces and some remain undiscovered

Question 20

Where are fossils from the simplest organisms found?

Answer 20

In the oldest rocks

Question 21

Where are fossils of more complex organisms found?

Answer 21

Recent rocks

Question 22

What does the evolutionary timeline reflect?

Answer 22

Ecological relationships, such as plants come before animal fossils as animals depend on plants for food

Question 23

What can be used to study evolutionary relationships?

Answer 23

Similarities in anatomy in fossils

Question 24

What is comparative anatomy?

Answer 24

Looking at comparable structures in organisms to add their knowledge about evolutionary relationships, because the fossil record has many gaps

Question 25

What are homologous structures?

Answer 25

Structures which seem to be different but are derived from the same basic pattern, such as arms

Question 26

What do homologous structures give evidence of?

Answer 26

Vertebrates have all evolved from a single common ancestor

Question 27

What is divergent evolution?

Answer 27

When a small group of individuals colonise a new habitat as a result of competition or migration

Question 28

What is embryology?

Answer 28

Source of evidence to show evolutionary relationships

Question 29

What is shown through embryology?

Answer 29

Many embryos look very similar, showing that animals develop in a similar way so have a common ancestral past

Question 30

What is comparative biochemistry?

Answer 30

Studies similarities and differences in proteins, DNA, RNA and other molecules when comparing different species

Question 31

How do molecules change?

Answer 31

Some molecules have changed over time, whilst some are highly conserved

Question 32

What can evidence in highly conserved molecules show?

Answer 32

The small changes can show highly conserved relationship

Question 33

What are biological molecules?

Answer 33

Certain molecules found throughout the living world

Question 34

What do closely related species contain?

Answer 34

Identical biological molecules

Question 35

What shows pattern of change?

Answer 35

Evidence from cytochromes and other proteins

Question 36

What is protein variation?

Answer 36

The central part of vital proteins such as DNA and RNA polymerase are similar in all organisms

Question 37

What is evidence from cytochromes?

Answer 37

Sequence of amino acid and changes int his seem to follow evolutionary instance of species

Question 38

What is neutral evolution?

Answer 38

Most of the variability in the structure of a molecule doesn’t affect its function as most of the variability occurs outside of the functional region

Question 39

Why are neutral changes neutral?

Answer 39

They dont affect function and their accumulation is not affected by natural selection

Question 40

How can you discover how closely related 2 species are?

Answer 40

Comparing the molecular sequence of a particular molecules

Question 41

How do you use evidence from comparison of a molecular sequence?

Answer 41

Plot the number of difference against the rate of molecule undergoes neutral base pairs substitutions so you can estimate which 2 species last shared a common ancestor as closely related species have more similar DNA and proteins

Question 42

What is commonly used to determine relationships between species?

Answer 42

Ribosomal RNA, as it has a very slow rate of substitution, with fossil information