Speciation and types of Isolation

If we all shared a common ancestor, then…

How did we diverge to become so many species? Descent with modification- Different Species

Video: How does speciation occur? https://www.youtube.com/watch?v=EmtIofdeUbc Click on the link to play video ~ 2: 40 minutes

What is Speciation? Definition: The formation of new and distinct species in the course of evolution Species: individuals capable of interbreeding with each other

There are two main types of speciation Allopatric and Sympatric speciation

Allopatric Speciation Definition: new species evolves as a result of geographic isolation

Allopatric speciation is caused by Geographic Isolation Definition: When a population is divided into two or more smaller populations due to PHYSICAL BARRIERS. Limits movement between individuals. Examples: (pick any 2) Rivers change course Mountains rise Continents drift

Harris’s antelope squirrel White-tailed antelope squirrel

Sympatric Speciation Definition: new species evolves from single ancestor while living in same geographic niche (organism’s “place” in ecosystem)

Sympatric speciation is caused by: Behavioral Isolation Definition: Two species do not mate because of differences in courtship behavior. https://www.youtube.com/w atch?v=z922by9_6Fw Example: Blue footed boobies (mating dance) Birds (mating song)

Bowerbirds courtship behavior Play video https://www.youtube.com/watch?v=U89tw093s_Y Approximately 2:07 minutes

Sympatric speciation is caused by: Temporal Isolation Definition: Populations may mate at different seasons or different times of day Example: 1. Frogs mating in early or late summer 2. Skunks mating in late winter vs. early summer

Mates during late winter Mates during late summer

Summary video over speciation Play Video clip https://www.youtube.com/watch?v=8yvEDqrc3XE

Your turn to practice Read the 10 scenarios on the handout and determine which type of isolation each scenario is describing. Geographic isolation Behavioral isolation Temporal isolation

Patterns of evolution

Who has seen the movie Divergent? What was it about?

- Tending to be different - Develop in different directions So what does the word DIVERGENT even mean? - Tending to be different - Develop in different directions

DIVERGENT

DIVERGENT

DIVERGENT

DIVERGENT

(aka Adaptive Radiation) Divergent Evolution (aka Adaptive Radiation) Definition: new species evolve from a common ancestor. Results when related species becoming more dissimilar from each other over time. Time

What do these have in common? Tiktaalik Human arm Whale Lizard Bird

Play from 2:00-3:40 and then 12:31-16:00 Origin of tetrapods Play from 2:00-3:40 and then 12:31-16:00 https://www.youtube.com/watch?v=zK8XGEDcTfo

Origin of tetrapods What does the word “tetrapod” mean? What are transitional fossils and why are they important? What evidence suggests that four-legged animals evolved from fish? Why is Tiktaalik considered a transitional fossil? Do you think the transition from fish to tetrapod happened quickly or slowly?

Origin of tetrapods Each table has a set of cards. Put them in order from oldest to most recent. HINTS  Remember that Tiktaalik is a transitionary fossil Flat heads evolved later Look at the evolution of the tail Look at the digits… webbing and quantity.

What is the correct order? Oldest Most recent - Eusthenopteron - Osteolepis - Panderichthys - Tiktaalik - Acanthostega - Ichthyostega - Tulerpeton - Hynerpeton - Pederpes

What do all these words have in common? CONFORM CONGREGRATE CONSPIRE CONVERGE CONSENSUS

- Coming closer together So what does the word CONVERGENT even mean? - Coming closer together

CONVERGENT

CONVERGENT

Convergent Evolution Definition: unrelated species become similar as they adapt and independently evolve to similar environments over time. Time

What do these have in common? They swim! Whale Ichthyosaur Porpoise

What taxonomic Class do they belong to? Whale Shark Ichthyosaur Porpoise

What do these have in common? They fly! Bat Dragonfly Cardinal

What taxonomic Class do they belong to? Mammal Bat Insect Dragonfly Aves Cardinal

What do all these words have in common? COWORKER COHORT COLLABORATE

Coevolution Definition: influence of closely associated species evolve together

COEVOLUTION EXAMPLE Hummingbird & Flower

COEVOLUTION EXAMPLE Host and Parasite

Read the following sentence silently in your head: Oh. My. Word. Sometimes. People. Make. Points. By. Writing. This. Way. I. Bet. You. Are. Pausing. After. Every. Word. In. Your. Head. This. Is. A. Lot. Of. Punctuation.

Which picture would you guess is PUNCTUATED EQUILIBRIUM or

Punctuated Equilibrium Definition: Evolution is stable for a time and suddenly jumps to new forms

If the picture on the left is PUNCTUATED EQUALIBRIUM, how would you describe the one on the right?

Gradualism Definition: New species evolve from existing species through gradual, often imperceptible changes

Let’s practice!

What Type of evolution is this? The kit fox lives in the desert where its coat helps disguise it from its predators. The red fox lives in forests where its red coat blends into its surroundings. Divergent Evolution

What Type of evolution is this? Yucca flowers are a certain shape so only that tiny moth can pollinate them. The moths lay their eggs in the yucca flowers and the larvae (caterpillars) live in the developing ovary and eat yucca seeds. Coevolution

What Type of evolution is this? There are species, found in Australia, Africa, and America. Though not related, they all evolved the "tools" necessary to subsist on an ant diet: a long, sticky tongue, few teeth, a rugged stomach, and large salivary glands. Convergent Evolution