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