The Origin of Species: Lizards in an Evolutionary Tree

Cara Larracas, Stacy Lopez, Takara Yaegashi

Period 4

Background Information

Throughout the Caribbean Islands there is a species of anole lizards that throughout time have evolved into different sub species. There are over 150 different types of anole with different niches depending on their environment.

Scientist found it interesting that on four most dominate islands Cuba, Puerto Rico, Jamaica, and Hispaniola. Each island has four main types of anoles. From there they started wondering how the each of the lizards got there.

Summary of Short FilmThe film demonstrates of how different types of anoles have different sized legs depending on where they live. The types of lizards they demonstrated were long legged runners, short legged twig, big canopy climber, and the trunk crown lizard.

The biologists thought of why anoles in Jamaica, Cuba, Hispaniola, and Puerto Rico had the similar body types. They concluded that all the anoles on the islands share a common ancestor. However they wondering how the anoles moved to the other islands from Cuba.

Key Concepts- An adaptation is a function that grants both

the greater ability to survive and reproduce. - Islands are the best places to carry out

experiments on the role of natural selection in driving populations because they are isolated and simple ecosystems.

- Microevolution is the evolution within a species while macroevolution means the changes that lead to a new species.

- Species means the group of individuals that reproductively and genetically isolated from other groups.

Key Concepts - When two groups of the same species become

geographically isolated, genetic changes will not be shared with the members of the other group and vise versa. Over time, they will differ as their traits change.

- For two groups to be different species, they must not mate or have fertile offspring with the other species even if they live in the same area.

- Comparing the DNA sequence between different species allows scientists to determine how different the two are and how long ago they shared the same ancestor.

Key Concepts

- Convergent evolution is when organisms in different evolutionary lineages evolve similar traits as a result to their environment or niche.

- One of the reasons why we see so many species on Earth is because there are many different types of habitats and niches.

Discussion Point:

● On contrary to Darwins claim evolution doesn’t always take a long period of time. Evolution varies from species to species.

● There were many species in that those area because it offers a variety of habitats and ways to survive.

● 2 groups that can’t reproduce fertile offspring with we each other are two different species. However in this video in particularly emphasizes that between the anole species ecologically isolated.

Discussion Point: ● A species will evolve in fewer

generations depending on the environmental situation. Species depend on the environment so if it changes then they need to change in order to adapt to them

○ Ex. when the two long legged anoles were moved onto an island with rock and small bushes by two to three generations the offspring had shorter and shorter legs.

Quiz QuestionWhich statement best explains why islands can be used as natural laboratories?

a. The climate of the islands varies from very wet to very dry.

b. Islands are small than the mainland so in sense the are like a lab.

c. The islands have similar habitats but they are different from the mainland’s habitats.

d. Since there are a lot of small islands, that means that researchers can repeat both observations and experiments on several similar islands.

Quiz QuestionWhat is microevolution?

A. An evolution within the world’s speciesB. An evolution within a speciesC. An evolution that makes a whole new speciesD. An evolution in a certain area.