Lizard Evolution

BENEFITS OF GENETIC DIVERSITY LAB - Lizard Evolution

Lab 3

Introduction

 

Before a researcher can ask how evolution may have produced many related species, it is necessary to carefully measure in what way these species are similar or different. With enough careful measurements a researcher can identify differences in traits among organisms and then begin to design experiments to understand what role natural selection might have played. The process of natural selection depends on genetic biodiversity.

 

Module 1 introduces you to the concept of grouping and categorizing animals according to their traits. You group lizards based on their general appearance using photographs, then take several measurement in order to compare characteristics of the lizard groups. You use these measurements to refine your lizard grouping and answer several questions based on these groupings. The techniques used to take these measurements are based on those used by scientists working in the field. Graphing data is an important way to objectively document differences and similarities. It can make it easier to spot patterns that would otherwise be difficult to see in tables of measurements or direct observations.

I would recommend trying it for yourself if you want to it is quite enjoyable and some of the features weren't so easily copied over to my blog site.  So if you want the full impact give it a try.  http://www.hhmi.org/biointeractive/lizard-evolution-virtual-lab

Procedure

 

1. Visit the Lizard Evolution Virtual Lab site
2. Enter the Virtual Lab.
3. Complete Module 1 only.

 

Questions

 

1. At the beginning of the virtual lab, you were asked to sort eight lizards into categories. What criteria did you initially use to make your groups?                                                                                                                                            I got four groups to start with.  I labelled then according to eye shape and the way their legs rested in the photos.
2. Did you revise your criteria later? Why?                                                                                                                                                 I did not go back and redo my grouping as I wanted to see if I was right to group them then I had.  Which it turns out I was very wrong as they all are same species, but have evolved along different paths.
3. An adaptation is a structure or function that is common in a population because it enhances the ability to survive and reproduce in a particular environment. Provide one example and an explanation of one adaptation in the Anolis lizards.                                                                                                                                                          The Anolis have adapted to different levels of the ecosystem some live on ground, some live on the tree base and some live high in the canopy.  This has helped them develop different traits such as leg size, coloration, tail length and appearance.   This allowed them to thrive in each habitat while looking very different and behaving differently as well.
4. Provide one evolutionary explanation for why lizards living in the same part of the habitat (i.e., grass) would have similar characteristics.                                                                                                                                           I think one reason they might have similar characteristics is that they both hunt the same food source so it makes it easier to catch the food that is more abundant for them which is why they evolved similarly. 
5. What is an ecomorph? Provide one example from the virtual lab.                                                                             An ecomorph is a habitat specialist and it is part of the same species, but each type of lizard (in this case) has evolved to fit a different ecological niche.
6. How is an ecomorph different from a species?                                                                                                                                    It is different from a species because they can be the same species, but have evolved with different characteristics.
7. Explain how a particular body feature of one of the lizard ecomorphs from the virtual lab is an adaptation to their particular niche.                                                                                                                                         The trunk crown anoles have adapted to their environment by developing larger toepads compared to other anoles at the base of the trees.  These toepads have allowed them to live high in the canopy and cling to leafs whereas the other lizards toes would slide off the leafs.

 We recorded tail length, hind length, body length and toe pad count.  My initial measurements were off so I redid them to match according to the sample provided.

Your Measurements Table
	A. evermanni	A. cristatellus	A. occultus	A. pulchellus	A. olssoni	A. coelestinus	A. cybotes	A. sheplani
Hindlimb Length	39.2 mm	44.8 mm	14.5 mm	26.7 mm	33.0 mm	40.6 mm	51.2 mm	14.0 mm
Body Length	47.6 mm	57.6 mm	33.3 mm	38.4 mm	41.2 mm	60.5 mm	61.6 mm	36.4 mm
Tail Length	107.8 mm	115.7 mm	38.4 mm	109.1 mm	142.1 mm	137.0 mm	124.7 mm	44.3 mm
Lamellae Count	45	31	25	32	31	46	31	21

Reference Measurements Table
	A. evermanni	A. cristatellus	A. occultus	A. pulchellus	A. olssoni	A. coelestinus	A. cybotes	A. sheplani
Hindlimb Length	41.8 mm	49.0 mm	16.8 mm	30.8 mm	38.9 mm	45.5 mm	57.2 mm	15.2 mm
Body Length	47.7 mm	58.5 mm	34.3 mm	37.9 mm	41.8 mm	60.9 mm	63.3 mm	36.9 mm
Tail Length	113.0 mm	118.3 mm	39.8 mm	115.2 mm	147.2 mm	139.6 mm	129.1 mm	44.9 mm
Lamellae Count	45	31	25	32	29	46	31	21

 

Your Measurements Table
	A. evermanni	A. cristatellus	A. occultus	A. pulchellus	A. olssoni	A. coelestinus	A. cybotes	A. sheplani
Lamellae Count	45	31	25	32	29	46	31	21
Relative Hindlimb Length	0.88 mm	0.84 mm	0.49 mm	0.81 mm	0.93 mm	0.74 mm	0.90 mm	0.41 mm
Relative Tail Length	2.37 mm	2.01 mm	1.16 mm	3.04 mm	3.52 mm	2.29 mm	2.04 mm	1.22 mm

Reference Measurements Table
	A. evermanni	A. cristatellus	A. occultus	A. pulchellus	A. olssoni	A. coelestinus	A. cybotes	A. sheplani
Lamellae Count	45	31	25	32	29	46	31	21
Relative Hindlimb Length	0.88 mm	0.84 mm	0.49 mm	0.81 mm	0.93 mm	0.74 mm	0.90 mm	0.41 mm
Relative Tail Length	2.37 mm	2.01 mm	1.16 mm	3.04 mm	3.52 mm	2.29 mm	2.04 mm	1.22 mm

 

 Unfortunately I was not able to format and get my bar graph up showing the living areas of the different lizards.