Ch 29, 30 Evolution I & II

Question 1

Why a newly found organism cannot be identified using a key

Answer 1

• A key is constructed based on the morphological characteristics of existing organism found

Question 2

How to collect more information which can be used for deciding whether an organism belongs to a phylum

Answer 2

• Carry out a comparative study about the amino acid sequence of DNA template of similar proteins found in the organism and other organism in the phylum to establish the phylogenetic relationship between them

Question 3

What is fossil

Answer 3

• The preserved remains or traces of ancient organisms

Question 4

Natural selection

Answer 4

• Genetic variation exists among the population, some are A and some are B
• Individuals with A have better ability to…
• They have a greater chance to survive and reproduce
• The proportion of individuals with A increases in the population of subsequent generations

Question 5

Speciation

Answer 5

• Groups of the same species were isolated by…
• They could not interbreed and there is no gene flow between them
• Due to random mutations, different genetic variations exist in different group of the species
• Due to different sets of environmental conditions, each group evolved differently by natural selection
• After many generations, genetic variations accumulated and different isolated groups could no longer interbreed to produce fertile offspring and they became different species

Question 6

Limitations of fossil study

Answer 6

• Missing links in fossil records that indicate the intermediate forms between related groups of organisms
• Incomplete or damaged fossil records give incomplete record of organisms in the past
• Fossil found in inaccessible areas are unavailable for study
• Organisms with soft body may not be fossilized

Question 7

Using amino acid sequence to determine phylogenetic relationship

Answer 7

• The fewer number of different amino acids, the closer the phylogenetic relationship
• Each amino acid in a polypeptide is coded by a genetic code in the DNA
• Mutation in a codon result in a different amino acids being incorporated in the polypeptide
• Organisms with closer phylogenetic relationships have fewer mutations, resulting in more similar genetic code

Question 8

NOS related to Lamarckism vs Darwinism

Answer 8

• Science is a progress of ongoing enquiries
• Scientific knowledge is tentative and subject to change
• Science is affected by social and cultural factors
• Scientists are both collaborative and competitive