3.4.5 species and taxonomy

Question 1

define species

Answer 1

a group of similar organisms that are able to successfully reproduce to give fertile offspring

Question 2

what is courtship behaviour?

Answer 2

behaviour carried out by organisms to attract a mate of the same species

Question 3

give examples of simple courtship behaviour

Answer 3

• releasing pheromones (chemicals)
• mating calls
• visual displays

Question 4

give examples of complex courtship behaviour

Answer 4

• dancing
• building nests

Question 5

what does courtship allow?

Answer 5

1. species recognition - only members of the same species respond
2. allows identification of a mate that is capable of breeding

Question 6

how are organisms classified?

Answer 6

1. Artificial classification : OLD METHOD
   groups organisms according to characteristics
2. Natural classification : based on evolutionary history (phylogeny), groups of organisms with shared features derived from a common ancestor, arranges organisms into a hierarchy

Question 7

outline the taxons of a hierarchy in order

Answer 7

1. Domain
2. Kingdom
3. Phylum
4. Class
5. Order
6. Family
7. Genus
8. Species

Question 8

what are problems with classification?

Answer 8

• you may not always be able to see organisms reproductive behaviour :
  they may be extinct
  they may not reproduce asexually
  there may be ethical issues

Question 9

how can species be classified based on similarities and differences in genes?

Answer 9

1. Comparing primary structure or polypeptides and proteins codes for by gene
2. Comparing DNA sequences
3. Comparing mRNA sequences

Question 10

what are examples of gene technologies?

Answer 10

1. DNA hybridisation
2. DNA sequencing
3. Comparing amino acid sequences
4. Immunological comparisons of proteins

Question 11

outline how you would carry out DNA hybridisation

Answer 11

1. DNA from different species is collected and separated into single strands by heating it heating breaks hydrogen bonds
2. Mix the separated strands and cool
3. Where base sequences are complementary hydrogen bonds reform some original double helices and some hybrid DNA
4. The more hydrogen bonds that form the more similar the DNA base sequences in each of the DNA strands
5. The DNA is gradually heated a 2nd time to separate hybrid DNA strands temperature of separation is recorded
6. Greater temperature needed to separate the DNA hybrid strands the more closely related