Unit Two, Day 2 Origins of Life

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

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

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

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

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.

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

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

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

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

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

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.

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

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

Speciation, Visually

Make it happen scientists!! Count off 1-7

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