41. What does it mean to say that all organisms are related genetically 42. Comp

Question

41. What does it mean to say that all organisms are related genetically

42. Compare AND contrast prezygotic and postzygotic isolating mechanisms. Describe some pre-zygotic isolation mechanisms and discuss how these would lead to speciation.

43. What are some ways we distinguish different species?

44. What is the difference between allopatric and sympatric speciation? Discuss some different types of sympatric speciation.

45. If presented with a phylogenetic tree drawing, be able to label tips, nodes, branches, taxa, sister taxa, monophyletic group, some homologous or convergent characteristics.

46. What can lead to an adaptive radiation?

47. If given some different types of data (anatomical, behavioral, molecular) be able to draw a simple phylogenetic tree of relationships between species.

48. How did the elaborate tail feathers of a peacock evolve?

49. If given a phylogenetic tree and/or other data be able to delineate species boundaries by applying the biological or phylogenetic species concepts.

50. What are all the diversification processes that have led to the diverse assemblage of freshwater fishes, snails, and mussels in the Lower Mississippi River Basin?

Explanation / Answer

41. All living organisms are related genetically. About 355 genes are common to all species. (In phylogenetic tree) all living organism share a common genetic heritage that is universal common descent (has a common ancestor) and due to evolution ends up in many species. LUCA (Last Universal Common Ancestor).

42. Reproductive isolation is the mechanism that keep species from mating with others and forming a hybrid. Prezygotic isolation prevents the fertilisation of eggs. Postzygotic isolation prevents the formation of fertile offspring.

Prezygotic reproductive isolation mechanisms are Habitat, Behavioural, Temporal, Mechanical, Gametic.

Habitat - Living organism from different areas cannot mate as they are far away to meet either.

43. Species is the basic unit of a biological classification and a taxonomical rank.

Analysis of morphology and DNA analysis can be used to distinguish species.

(Comparison of the secondary structure of ITS2 transcripts reveals its most conserved region, on the 5'-side of helix III).

44. Speciation is the formation of new and distinct species in the course of evolution.

There are 4 types of speciation 1)Allopatric 2)Peripatric 3)Parapatric 4) Sympatric

Allopatric speciation occurs when species separtes into two groups and are isolated from one another by physical barriers such as mountain or river etc.

Sympatric speciation has no physical barrier, they are in close proximity and forms a new species due to environmental factors (shelter, food source).

46. Adaptive radiaton is the diversification of a lineage into species that exploit a variety of different resource types and that differ in the morphological or physiological traits used to exploit those resources.

48. Theory of sexual selection

References:

1. https://www.jstor.org/stable/2463047?seq=1#page_scan_tab_contents

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