1. Unit Two, Day 2
Origins of Life

2. Opener What is speciation?
Write your answer on the big white board up front!
5 minutes

3. Agenda Evidence of Evolution Assessment Friday
Updating your Reading Comp 4 is your study guide
Processes of Common Ancestry
Reproductive Barriers

4. Homework Read Chapters 24.2-24.4
Essential Question: What mechanisms lead towards speciation?

5. Cornell Notes
Title: Speciation Essential Question: What common processes do all living things share?

6. New LT #1
I can identify and describe processes and features shared by all life, and explain how these processes and features support the idea of common ancestry for all organisms
Quick blast of info: this mini-lecture, and the video on the website. That’s it.

7. The Domains of Life Common Ancestor Bacteria Archaea Eukarya
All living things can be divided into three groups, called DOMAINS.
Common Ancestor
Bacteria
Archaea
Eukarya

9. Common features of all three domains
Genetic Code
Central Dogma
Metabolic Pathways

10. Genetic Code: code of life
DNA/RNA as carriers of genetic information
DNA bases: A, T, C and G
RNA bases: A, U, C and G
Universal Genetic Code:
Base order=information stored in DNA/RNA
What the order “means” is always the same

11. Central Dogma Transcription: Information in DNA copied into RNA
Translation:
RNA information used to make a protein
Ribosomes—found in ALL cells
Traits: ALL of our traits, visible or not, are in some way determined by a protein

12. Metabolic Pathways
A metabolic pathway is a series of chemical reactions
Purposes: producing energy, making something, breaking something down
Photosynthesis
Synthesis of sugars using light energy
Cellular Respiration:
Glycolysis: extracting energy from glucose (simple sugar)
Energy carrier: Adenosine Triphosphate: ATP

13. THERE ARE NO ALTERNATIVE STRATEGIES IN DIFFERENT FORMS OF LIFE.
What does this tell us?
ALL life shares a common ancestor with these traits:
DNA/RNA based genetics
Central Dogma
Simple metabolic pathways/ATP
If this WASN’T true, what would we see?
Different strategies, in different life forms, for:
Storing genetic info
Turning that info into traits
Getting energy
THERE ARE NO ALTERNATIVE STRATEGIES IN DIFFERENT FORMS OF LIFE.

14. New LT #2 I can explain the mechanisms of speciation
Supporting targets:
I can define the biological species concept
I can describe the importance of reproductive barriers in speciation
I can distinguish between pre and post-zygotic reproductive barriers
I can identify and describe the seven types of reproductive barriers
I can give example of speciation that resulted from each type of barrier

15. Speciation The Biological Species Concept:
Defines a species as a group of organisms that can/will breed and produce offspring in nature
Speciation: an evolutionary process that produces one or more new species from an existing species
What conditions lead to speciation?
Reproductive Isolation
some barrier that prevents members of a population of the same species from breeding
SO there is a reduction in gene flow
Evolution: through natural selection
Two kinds of barriers:
Pre-zygotic: prevents mating, or formation of a zygote
Post-zygotic: mating happens, offspring not ok

16. Speciation, Visually

17. Make it happen scientists!!
Count off 1-7

18. Mini-Poster Types of Barriers
Do: Work your group to complete the mini-poster assignment
Use: Book (Section 24.1), Internet
Time: 30 minutes
Habitat Isolation
Temporal Isolation
Mechanical Isolation
Behavioral Isolation
Reduced Hybrid Viability
Reduced Hybrid Fertility
Hybrid Breakdown