10.4

Question 1

What is evolution?

Answer 1

• Evolution is the theory that describes the way in which organisms evolve or change over many years as a result of natural selection
• Organisms better suited to their environment are more likely to survive and reproduce, passing on their characteristics to their offspring
• Gradually, a species change over time to have a more advantageous phenotype for the environment in which it lives, as it passed from one generation to the next by genes.

Question 2

What did Darwin observe on the Galapagos?

Answer 2

• Islands had different flinches
• They were similar in many ways, but had different beaks and claws of different sizes and shapes
• The design of the flinches beak was linked to the foods available on each island
• A bird with a better suited beak to the food available would live longer than a bird who’s beak was less suited
• Therefore they would pass this trait onto their offspring and over time the finch population on their island would share this characteristic
• Presented the theory of evolution by natural selection

Question 3

What are the 3 evidences of evolution?

Answer 3

• palaeontology- study of fossils and the fossil record
• Comparative anatomy- study of similarities and differences between organisms anatomy
• Comparative biochemistry- similarities and differences between the chemicals makeup of organisms.

Question 4

What is palaeontology?

Answer 4

• Fossils are formed when animals and plant remains are preserved in rocks.
• Over long periods of time, sediment is deposited on to the earth to form layers (strata) of rock.
• Different layers correspond to different geological eras
• Fossils van be dated to put fossil organisms in a sequence
• Similarities can be shown
• However, it is not complete because soft bodied organisms can decompose quickly before they had the chance to fossilise

Question 5

What is comparative anatomy?

Answer 5

• A Homologous structure is a structure that appears structurally similar and may perform different functions in different organisms.
• Example is pentadactyl limbs
• Vertebrate limbs are used for a wide variety of functions such as running, jumping, hoping and flying,
• The basic structure of limbs are adapted to carry a wide range of functions, since they come from the same common ancestor.
• Presence of homologous structures provides evidence for divergent evolution
• Convergent evolution is when unrelated organisms have similar structures that have similar structures

Question 6

What is comparative biochemistry?

Answer 6

DNA found in the nucleus of cells can be sequenced and used to provide evidence of evolutionary relationships between species and how genetic code of species have changed over time

• DNA hybridisation: enzymes are used to cut up DNA and an electric current is run through so they are attracted to the negative end
• pattern in which they move can be compared
• degree of similarities in the DNA sequence can determine evolutionary relationships
• more closely related, more hydrogen bonds and higher temps are needed to break the hybrid DNA (2 strands stuck together)

Question 7

What is behavioural evidence?

Answer 7

Humans are classified as primates because

• longer period in parental care
• live in social groups
• vocalisation and facial expression

Question 8

What is the immunological evidence?

Answer 8

• how different immune system responds
• inject rabbit with human serum (blood without cells)
• the rabbit will develop antibodies against the antigens
• more green cloud= more precipitation=more in common as the rabbit and chimp antigens react