Question

Question 10: Anolis lizards are a genus of closely-related lizards that have evolved into many different morphs on various Caribbean islands and surrounding mainlands. Harvard scientist Jonathan Losos has classified these morphs into 6 types that specialize on and appear to be adapted to different microhabitats organized along vertical space. For example, "twig" (specializing on twigs) lizards have short legs with a slender body, whereas "trunk-ground" lizards have long hind legs with stockier bodies. Interestingly, similar patterns of morph diversification are observed on the major islands: Puerto Rico, Jamaica, and the Bahamas (Figure 2). Furthermore, each species of Anolis living in the same area has evolved different dewlaps (neck flaps) that are used in communication and visual displays for mating Trunk-ground A. lineatopos Trunk-crown 4. grahami JAM Twig - A. valencienni A. sagrei 4. carolinensis BAH A. angusticeps - Aevermanni - A. gundlachi Figure 1. Phylogeny of Anolis (A. spp) lizards on three islands. Lizard type (habitat specialization) is indicated to the right of each species name using shaded boxes (see paragraph for details). The island on which each species is found is shown using abbreviations: JAM - Jamaica, BAH - Bahamas, and PR - Puerto Rico Use the phylogeny to answer these questions (and be able to explain your answers): A) How many monophyletic groups are shown on this tree? ("Groups can be defined by either habitat or location on a particular island). B) What is the most recent common ancestor of the species that live in the Bahamas? c) What inferences can you draw from this tree regarding the pattern of colonization and speciation in this group of lizards? For example, can you tell which island was probably colonized first or last? Were any islands colonized multiple times? Did any sympatric speciation events occur (le, within the same Island)? D) What was the most likely habitat specialization of the most recent common ancestor of all the Anolis species on the tree? E) How many times has the twig morph been gained?

Answer 1

A) Here their asympatric speciationre 3 monophyletic groups if the groups are defined on the basis of habitat as mentioned in the question.

B) The recent common ancestor for these lizard species in the bahamas is the point from where all other species started to evolve ( I have attached a image, u can please refer that to get the answer).

C) It seems like the jamican island were colonised later than that of the other and the first one to be colonised was the puerto rico because we can observe that the evolutionary time taken by all the successors of the common ancestor on the jamican island is less whereas on the bahamas and puerto rico the evolutionary time taken is very more and they seem to be colonised during the same time period and earlier than that of the jamican islands. We ca see that their is genetic similarity observed between a lizard species A. sagrei which is species which belongs to the bahamas but has genetic similarity to the lizards of the jamica so based on this example we can say that their are chances of multiple colonisation. Moreover sympatric speciation is a result of reproductive isolation,yeah we can observe on the puerto rico island that their are two different species two different morphs this can be result of sympatric speciation.

D) Twig morph is the best suitable for those living on trees.#

E) 2 times the twig morph has been gained.

AS- Camlin Page Date 1 (6 typen) twig, trunk ground, . A. lineatapus - Agraham - A. valecienni - A sagni - A. Carolinensis A. angushine Aeverman A.gundlachi most beant Common anaston