Lizards and Evolution

by Dino and Fifi

Our Study:
The topic of interest we identified for investigation is “How Lizards Evolved?” we were also interested in “Lizard Adaptations”.  We will study the evolution of Anole Lizards and then compare the  Plumed Basilisk Lizard to the closely related relative, the Smooth Helmeted Iguana.

Did you know…

  • it is believed that lizards have been around for 200 million years
  • there is a Chameleon in Madagascar which is 1 inch long
  • some species of lizards can squirt blood from their eyes a distance of feet
  • Chameleons change colours to blend with their surrounding
  • some lizards even look like they have a third eye on their head
  • There are more than 5,600 different species of lizards

Anolis lizards
One of the first sites we found was the Lizard Evolution Virtual Lab.
This study had to do with the work of biologist Jonathan Losos.  While working in the islands of the Caribbean, he discovered the traits that enable dozens of anole species to adapt to different vertical niches in the forest. Differences in limb length, body shape, and toepad size allow different species to live and grow and reproduce on the ground, on thin branches, or high in the canopy,

Grass / Bush AnoleTrunk / Ground Anole
Twig AnoleCanopy Anole

Below is a table showing how the specific traits of 4 different species of Anole Lizards allow them to live and reproduce in their preferred natural habitat.

NameHabitatLeg Length / Body / TailToe Padother info
Grass / Bush Anolelives on grass and bushesVery Long Tails and Slender Bodyruns and jumps
Trunk / Ground Anolelives on the groundStocky, Longer Leggedtoe pads made for running on trunksquite fast, runs
Twig Anolelives on branches and twigs Short leggedhave small toe pads design for holding or hugging twigsnot as fast as other anoles
Canopy AnoleHigh up in the CanopyLarge in body lengthVery Large Toepadshave little hairs on their toe pads that cling or bond to the surface of large leaves in the canopy

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.

Can You Observe Body Traits in Anole Lizards Evolve?
What happens when you put Long Legged Tree Anoles on islands with no trees?   Dr. Losos’s conducted an  experiment, where he  took a pair of tree dwelling trunk anoles from a large island and relocated a male and a female to seven small islands that had been depleted of trees from a recently hurricane. The small islands have only small bushes and grass. These small experimental islands or laboratories lacked any lizards until the pair was place there.

Each year Dr. Losos returned to the islands and collected data on the lizards.   Dr. Losos’s data suggest that after only a few generations, the lizards on the experimental islands developed shorter legs on average than the lizards on the larger island.  Based on the data collected from the experimental islands and the lizards that were placed on these islands,   the average leg length of the population had shorten in just 2 two generations. Over the next 4 years the trend continued showing that evolution can occur very rapidly when natural selection is strong.

How did the four anole species come to be so different from one another?Reproductive Isolation and Speciation in LizardsHHMI BioInteractive Video   <;>

For a species to be considered a new species they cannot breed with the old species, this is called reproductive isolation.  The scientist, Dr. Losos wondered what kept the 4 anoles from mating with eachother.  He discovered that anoles with different dewlaps stayed away from eachother.  Only anoles with the same colour dewlaps mated.

Male Carolina anole (left); male brown anole (right)
Rapid Evolution in Real Time by Science Daily. WIKIMEDIA, R. COLIN BLENIS (L), HANS HILLEWAERT (R)

Changes in other characteristic traits, such as their colourful dewlaps, have played a key role in reproductive isolation and the formation of new species.


Lizard Evolution Virtual Lab

THIS IS A PART OF The Origin of Species: Lizards in an Evolutionary Tree


NEXT we want to EXPLORE the Adaptations of the Plumed Basilisk  Lizard and compare them to a closely related the Smooth Helmeted Iguana 

Corytophanidae  is the  family of iguanian lizards, the Plumed Basilisk belongs to.  This family is sometimes called the casquehead lizards or helmeted lizards.  The Smooth Helmeted Iguana belongs to the same family but has evolved very differently.

To begin with look at how cool the Plumed Basilisk  Lizard is.

male plumed basiliskfemale plumed basilisk

these little guys can run really fast across the water to catch food.

The Smooth Helmeted Iguana is equally cool.

smooth helmetedsmooth helmeted

these little guys can change their colouration to blend in to their enviroment.


Meet the Jesus Christ Lizard by  National Geographic.<>

Plumed Basilisk Lizard Care Tips by Leo Spinner

Plumed Basilisk

Smooth Helmeted Iguana