5/18/2015•Hello!•Please remember to ask to leave the room

- Have your review HW out to be checked in.- While I check it in you should discuss any 7.1

review questions with your table• 7.1 exit slip• Start 7.2• Activity: Time and Speciation• HW: Finish your timeline! SP 0.4!• Reassessment is THURSDAY. Please sign up

in the front of the room on the clipboard. You can come any time, ends at 3:05.

• Elite? See me at end of class!

Where are we?•Pull out your Unit 7 Rubric.

• 1st assessment for 7.1• Starting 7.2 Today!

• Ppt review of 7.2-L1 Take notes Posted after the B day

7.2 - Students understand how macroevolution explains the diversity of life on the planet

Chapter 16p.303-316

VOCABSpeciationGeologic time

scaleBiodiversityExtinctionPhylogenetic treeMacroevolution

L1Explain the mechanism of speciation

L2Explain barriers of reproduction between two species

L3Analyze phylogenetic trees of evolutionary history

Two Ways We Look At Evolution

Microevolution• Changes in a gene

pool of a population

• E.g. a population accumulating; darker fur genes or “higher fitness number” genes

Macroevolution• The formation of

new species or taxonomic groups!

• Includes: How did animals evolve? How did mammals evolve? Etc!

We just finished this ☺

Moving on to this!

Macroevolution

Big Changes

Can Selection Alone Cause Big Changes?

• YES!

Macroevolution

• Is concerned with how new taxonomic groups or species came to be

• Ex: How did mammals evolve from ancestral reptiles??? so…taxonomic groups!

The Taxonomic Groups is how we organize all the organisms on the Earth!

• Domain• Kingdom• Phylum• Class• Order• Family• Genus• Species

JIC: Pneumonic Device – YOU DO NOT NEED TO MEMORIZE FOR QUIZZES • Dude

–Kings• Play

–Chess»On

• Fancy• Gold

• Sets

Ex: Cat Taxonomy

• Domain– Kingdom

• Phylum– Class

» Order• Family

• Genus• species

• Eukarya– Animalia

• Chordata (vertebrates)– Mammalia

» Carnivora• Felidae

• Felis• catus

ExampleFelis Catus

Felis

Zoom in on Order Carnivora!

Scientific Names are based on Taxonomy

• Genus species of taxonomy put together and put in italics.

• Ex: humans are Homo sapiens/H. sapiens

• Ex: Domestic cat is • Felis catus • aka: Felis domesticus or

Felis silvestrus

Modern Goal of Taxonomy

• Identify which species are most closely related to which

• E.g. which fossils we find represent ancestors, which represents cousins?

Speculative, but not a leap of Faith

7.3 – the Evidence!

Microevolution→ Macroevolution

So tell me….What defines a species???

*Note*• Species (and other taxonomic

levels) organizes nature into neat little boxes.

• Nature don’t work like that…our brains do! So…– Lots of exceptions to the rule, e.g.

hybrids, dogs/wolves etc.– Difficult to classify asexual species– Very difficult to classify extinct

species

Different Species…• Cannot naturally combine gene pools

• Cannot have fertile, viable offspring**

Picture by Mrs. Sweis

• Appearance can be misleading in determining a species.

Same species or different species?

Members of Different Species May Be Similar in Appearance

Members of SAME Species May Differ in Appearance

Same species or different species?

Speciation is the process by which new species form

1. Populations Isolated• No gene flow between

them• May be physically

(allopatric) or within an area (sympatric)

2. Populations genetically diverge

• Populations adapt differently and accumulate genetic differences

• Eventually they are too different to reproduce

Part of a mainlandpopulation reachesto an isolated island

Divergence may eventuallybecome sufficient to causereproductive isolation

The isolated populations beginto diverge due to genetic driftand natural selection

Allopatric Isolation and Divergence

Part of a fly population that lives only on hawthorn trees moves to an apple tree

The flies living on the apple tree do not encounter the flies living on the hawthorn tree, so the populations diverge

Sympatric Isolation and Divergence

Fig. 16-10

Is this Plausible? • Yes!• There is observed experimental evidence of

speciation.

Micro + Macro → The Big Picture!-Darwin’s BIG IDEA

-natural selection takes place in populations that are isolated

-over LONG periods of time, small changes in allele frequencies from gen to gen can add up to BIG changes in species. -This leads us again to the idea of a universal common ancestor.

But How Could This

Evolve from this?

Very Gradually Over 4 Billion Years

• https://www.youtube.com/watch?v=hsHwCc9C3GA

 

How Much is a Billion? (compared to a million)

•1 million seconds = about 12 days

•1 billion seconds = about 32 years

•1 million minutes ago was approximately 2 years ago

•1 billion minutes ago was the year 114AD

•1 million hours ago it was the dawn of the 20th century (1901)

•1 billion hours ago was around the time we think the first modern humans walked (141k ya)

•1 million days ago it was about 700BC

•1 billion days ago was 2.7 million years BC

To Understand the Evolutionary Timescale

• Each person gets 92cm worth of paper• Scale out 4.6 billion years on that paper

(the approximate age of the Earth)–The 4.6 billion years should use up all 92

cm. Why are we asking you to use 92 cm HINT HINT…

–Check with your teacher to see if your scale is appropriate

NEXT…

• Pick 10 MAJOR events in the history of the Earth (and life)– Do not focus on human events! You have 4.6

billion years to look at!• Get this list approved • Identify approximately when they occurred

and place a sketch or small picture at the appropriate point. Label what happened

E.g. if you did the last 20 years

Toda

y

2 ya

6ya

10ya

20ya

4 ya

8ya

12 y

a

16ya

14 y

a

18ya

MJ 6-peats You all are born Y2k is a bust9/11 Iraq War Obama Elected Burj Khalifa

New Jones Built

HOMEWORK•Finish your timeline and bring it to class SP 0.4, fill out your survey!

•ELITE: come see me now•Optional HW:

–Come to Ac Lab and review your last Unit test–Read the corresponding pages in the wolf book. –Review this power point on the HHW