4.2.2 Classification and evolution

Question 1

what is classification

Answer 1

• the name given to the process by which living organisms are sorted into groups

Question 2

what is taxonomy

Answer 2

• the study of the principles of classification

Question 3

what is phylogeny

Answer 3

• the study of evolutionary relationships between organisms

Question 4

what are the 7 taxonomic groups in order of hierarchy

Answer 4

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

Question 5

why so we classify organisms

Answer 5

• to identify species
• to predict characteristics
• to fine evolutionary links
• helps communication

Question 6

historically, how were species classified

Answer 6

• based on observable features
  > artificial classification

Question 7

how are species classified now compared to before

Answer 7

• based on DNA and biochemistry
  > molecular biology
  > natural classification

Question 8

what happens as you move down the heirarchy

Answer 8

• more groups at each taxa but fewer organisms in each group
  > organisms in each group become more similiar + share more of the same characteristics

Question 9

what are species

Answer 9

• the smallest basic taxonomic unit used to define living organisms
  > they’re a group of individuals with similiar key features but show variation + are able to interbreed and produce fertile offspring

Question 10

what is the binomial nomenclature

Answer 10

• system used to name species
  > Genus species

Question 11

what are the 5 kingdoms

Answer 11

• prokaryotae (bacteria)
• protoctista (unicellular eukaryotes)
• fungi (yeast, mould, mushrooms)
• plantae (plants)
• animalia (animals)

Question 12

what are some features of prokaryotes

Answer 12

• unicellular
• no nucleus / membrane bound organelles
  > ring of ‘naked’ DNA - small ribosomes
• no visible feeding mechanisms - nutrients absorbed through cell wall or produced internally by photosynthesis

Question 13

what are some features of protoctista

Answer 13

• (mainly) unicellular
• has nucleus / membrane bound organelles
• some have chloroplast
• some = sessile but others move by cilia, flagella or amoeboid mechanisms
• nutrients acquired by photosynthesis (autotrophic feeders), ingestion of other organisms (heterotrophic feeders) or both
  > some are parisitic

Question 14

what are some features of fungi

Answer 14

• unicellular / multicellular
• has nucleus / membrane bound organelles + cell wall mainly composed of chitin
• no chloroplast / chlorophyll
• no mechanisms for locomotion
• most have body or mycelium made of threads or hyphae
• nutrients acquired by absorptions - mainly from decaying material - they’re saprophytic feeders - some are parastitic
• most store food as glycogen

Question 15

what are some features of plants

Answer 15

• multicellular
• has nucleus / membrane bound organelles + chloroplast + cells wall made of cellulose
• contain chlorophyll
• most don’t move, although gametes may move by cilia / flagella
• nutrients acquired by photosynthesis - autotrophic feeders - organism makes own food
• stores food as starch

Question 16

what are some features of animals

Answer 16

• multicellular
• nucleus / membrane bound organelles (no cell wall)
• no chloroplast
• move with air of cilia / flagella or contractile proteins in muscular organs
• nutrients acquired by ingestion - heterotrophic feeders
• store food as glycogen

Question 17

what can prokaryotae be divided into

Answer 17

• Eubacteria
• Archaebacteria=

Question 18

give the difference between archaebacteria + eubacteria

Answer 18

• archaebacteria is ancient bacteria that lives in extreme conditions
  > hot, anaerobic, highly acidic
• eubacteria is true bacteria which is found in all organisms and are ones we are most familiar with