Lesson 5 - Speciation

Lesson Objectives

A. Introduction

Speciation is the formation of a new species from a population.  A species is a group of organism that are capable of reproducing and producing fertile offspring.  A new species will not be able to reproduce with the "old" species.  This is speciation.  In order for speciation to occur, isolation is needed.  In this case their are barriers to reproduction.  This lesson will explore some of the ways that reproductive isolation can occur.  Some of these examples include parapatric speciation and sympatric speciation.  As the two groups become more genetically isolated, allele frequency differences increase; this is the first step towards speciation.  As this happens and more differences in alleles across different genes build up, a new species can develop.

B. Content Objective: Explain how different types of isolation can result in the formation of a new species.

C. Language Objective: Create a flowchart showing the process of speciation. Including and expanding on the following ideas:

-gene flow between two populations is interrupted

-genetic differences (allele frequency differences) gradually accumulate between the two populations

-reproductive isolation as a consequence of this divergence

E. Syllabus:

i. Populations of a species can gradually diverge into separate species by evolution

ii. Continuous variations across the geographical range of related populations matches the concept of gradual divergence

iii. A gene pool consists of all the genes and their different alleles, present in an interbreeding population.

iv. Evolution requires that allele frequencies change with time in populations.

v. Reproductive isolation of populations can be temporal, behavioural or geographic.

vi. Speciation due to divergence of isolated populations can be gradual (Punctuated equilibrium and gradualism) 

vii. Species are groups of organisms that can potentially interbreed to produce fertile offspring.

viii. Members of a species may be reproductively isolated in separate populations.

ix. Skill: Comparison of allele frequencies of geographically isolated populations. (We will do this in class)

Activites

Activity 1  - Pre-Lesson Work

Expectations: Create a set of mind-mapping notes, using any of the links below.  The notes should address all the syllabus statements above. 

Menus:

Video:

Khan Academy - Stop at 7:49 (v - viii)

Allele Frequency - (i, ii, iii,iv) - Focus on the big details

Reading:

Causes of Speciation - Understanding Evolution (v, vi)

Reproductive Isolation - Understanding Evolution (v)

Khan Academy Reading - Skip pre-zygotic and polyploidy (i, ii, v-viii)

Bioninjia - Speciation and Alleles - Skip ALFRED database - (iii, vi)

Activity 2 - Allele Frequency Changes

Activity 3  

Create a recipe that shows how to get speciation to occur with one type of isolation. Include "ingredients" and at least 8 step-by-step directions.

Include:  types of isolation (allopatric, temporal, sympatric), the definition of a species, variation, natural selection (include the conditions), gene flow between two populations is interrupted, allele frequency differences gradually accumulate between the two populations in many different genes, reproductive isolation is a consequence of this divergence.

On Google Classroom

Pre-Notes and Activity 3

Due dates on your homework page.

Home Learning

A. Strengthen Your Skills

Speciation - Ameoba Sisters

Mr. C's How does speciation occur? 

In Darwin's Footprints

 B.  Expand Your Knowledge

Going up: Birds and mammals evolve faster if their home is rising

New piece of the puzzle increases understanding of speciation