Classification and Evolution

Question 1

What is the sequence of taxa in the biological hierarchy?

Answer 1

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

Question 2

What are the key physiological and structural differences between archaea and bacteria?

Answer 2

• Archaea have unique membranes
• Archea have a more complex form of RNA polymerase
• Only bacteria have peptidoglycan in their walls
• The genes and protein synthesis in archaea are more similar to eukarya than bacteria

Question 3

What are the characteristics of the kindgom protoctista?

Answer 3

• Mainly unicellular
• Have a nucleus and many membrane bound organelles
• Some have chloroplasts and chlorophyll to carry out photosynthesis and so are autotrophic
• Some ingest other organisms and so are heterotrophic
• Some are parasitic

Question 4

What are the characteristics of fungi?

Answer 4

• Some uni some multicellular
• Have a nucleus and other membrane bound organelles
• No chloroplasts
• Body made of hyphae
• Cell wall made of chitin
• Reproduce by spores
• Obtain food by by absorbing dissolved organic materials and so are saprophytic

Question 5

What is the evidence that has lead to new classification systems?

Answer 5

• Through the study of genetics and other biological molecules, scientists are now able to study the evolutionary relationships between organisms
• These links can then be used to classify organisms

Question 6

What are homologous structures, and what is their significance in evolution?

Answer 6

• Structures that appear different and may perform different functions, but have the same underlying structure
• All these organisms with this structure have evolved from a common ancestor

Question 7

Which molecules can be used to identify evolutionary relationships between organisms?

Answer 7

• Cytochrome c and rRNA are commonly studied molecules in comparative biochemistry because they are highly conserved among species
• Slight differences can help identify evolutionary links
• DNA molecules, mRNA and amino acid sequences can also be used to identify evo relationships between organisms

Question 8

What is the difference between anatomical and physiological adaptations?

Answer 8

• Anatomical - physical features that help and organisms survive and reproduce
• Physiological - processes inside an organism that increase its chance of survival/reproduction

Question 9

Outline the process of natural selection

Answer 9

1. There is variation in characteristics within a species
2. Random mutations in the gene pool may result in new alleles that produce advantageous traits
3. Organisms with advantageous alleles are more likely to survive and reproduce
4. Advantageous alleles are passed onto offspring
5. Over time, these alleles become more common in the population