topic 10 diagnosing species

Question 1

elephant ex - why hard to diangose?

Answer 1

very slight differences in morpholohy
traditionally one species in africa and another in asia
owever, recent morphological studies have pointed out that forest dwelling elephants in West Africa appear to differ from elephants found in Savannah habitats elsewhere on the continent
○ Forest elephants are smaller (usually <8 feet at shoulder vs. >10 feet for bush elephants), have a
longer thinner mandible, straighter tusks and usually 5 front toenails and 4 rear toenails vs. 4 front and 3 rear in bush elephants)
○ A comparison of DNA from 21 populations suggests that two phylogenetic species exist, and
it has been suggested by Roca et al. (2001) that forest elephants be named Loxodonta cyclotis
○ Whether the two populations are capable of interbreeding is unclear, but the clear genetic differences between populations suggest that
conservation biologists should be attempting to conserve members of both populations

Question 2

describe sibling species

Answer 2

• Reproductively isolated populations
• Difficult to distinguish by morphological Features
• Often recognized by ecological,
behavioural, and chromosomal differences

Question 3

• Recognition and diagnosis of a new sibling species - what is used to recognize them?

Answer 3

• Often recognized by ecological,

behavioural, and chromosomal differences

Question 4

ex of diagnosing a new sibling species - leaf beetles

Answer 4

• Futuyma’s study with Florida population of leaf beetles, genus Ophraella
• Host association differed from the usual for O. notulata
○ Some feed on Iva plant (commonly called marshelders) vs. Ambrosia plant (ragweed)
• Consistent differences in allele frequencies
• No evidence of hybridization
• Later found differences in average morphology
• Larvae strongly prefer different host plants
• In the lab, hybridization only possible with males from the new population
• Hybrids less viable and not able to reproduce
• New species Ophraella slobodkini (named by Futuyma) is a sibling species of O. notulata

Question 5

what are ring species?

Answer 5

• Connected series of neighbouring
populations, each of which can interbreed except the two “end” populations
• Gene flow occurs between neighbouring populations, but at the end of the “ring,” populations cannot interbreed = maintaining species status

Question 6

incipent species definition?

Answer 6

• Definition of incipient species
: a natural population that is more or less interfertile with another related population but is inhibited from interbreeding in nature by some specific barrier — compare ecospecies.
•

Question 7

what is dna barcoding

Answer 7

○ Method of species identification using a short sequence of DNA
○ By comparing with a reference library of such DNA sequences, an organism can be identified to species
○ A worldwide effort (International Barcode of Life, iBOL) to “barcode” or generate standard genetic sequence identification of all species on Earth

Question 8

• What is a barcode?

Answer 8

○ UPC (Universal Product Code) Symbol – 11 variable positions with 10 possible numbers
○ Ability to assign a unique identifier to over 100 billion items

Question 9

what is a dna barcode?

Answer 9

○ Use of a designated DNA sequence to serve as a unique species identifier
○ Ideal sequence is constrained by overall conservation (preserve gene function), but still has substantial sequence variation which differentiates species