Scribe Post: 2/14/11

TODAY, boys and girls, we finished our notes packet and worked on lab 32 in class (ooooooooooooooohhh) The notes taught us the names and characteristics of our evolutionary predecesor

• Homo habilis- "handy man"- enlargement of brain, lived in east Africa
• Homo erectus- extended territory to different parts of the world. Changes in diet included more meat consumption (from hunted animals), refined tools, taller, larger brain capacity (Thus more cognititve thought), lived in caves, built fires (hallelujah), social cooperation, African, Asian, European, and Austrailian.
• Neandarthals- (descendents of H. erectus/ precursor to H. sapien)- Heavier browridges (sloped foreheads, similiar to gorillas), less pronounced chins, slightly larger brain size than us, skilled toolmakers, burials and rituals, abstract thought. Stereotypical "caveman", found in Europe, Middle East and Asia.
• Homo sapiens- regionally diverse

- A.) Archiac Homo sapiens- oldest, over 300,000 years old, lived in Africa, Can include Neandarthals.

- B.) Cro-Magnon- like modern humans, lived in french caves (found cave drawings there), 35,000 years old.

- C.) Homo sapiens sapiens- Les humains modernes (modern humans :)

What happened to various H. Erectus descendents????

• Multiregional hypothesis- Modern humans evolved simultaneously around the world. Genetic similiarities due to interbreeding with neighboring tribes.
• "Out of Africa" hypothesis- (aka replacement hypothesis) Modern human arose from group in Africa and then spread around the world about 100,000 years ago. (Most widely accepted because of genetic backing)

Cultural Evolution-

• Erect stance- Most radical change in our evolution. Required MAJOR realignment of pelvis, feet, and spine.
• Enlargement of brain- secondary alteration-made possible by lengthened skull growth period. Accounts for lengthened parental care, and offspring learn from past generations.
• Culture- transmission of accumulated knowledge by writing or storytelling.

- 3 MAJOR CULTURAL STAGES:
Nomad, Agricultural, and Industrial.
Basicallly, we're more advanced than the "cavemen" because we've learnt from other's mistakes. We are no more smarter, but have the advantage of accumulated knowledge from past generations relayed to us by our parents, media, books, and TEACHERS (Thank you Mrs. Andrews :)


HOMEWORK:
- LAB 32 IN UP- DUE MONDAY
- TEST TUESDAY
- FINISH UP FOR TUESDAY :)


next scribe: Claire T.

2/9/11

Today, we took a quiz.
Notes:

Human Ancestry

• Early primates:
  
  evolved from insect-eating mammals during Cretaceous period (evidence from fossils)


• were small


• lived in trees (arboreal)


• limber shoulder joints


• could grab with their hands (dexterous)


• nails started replacing claws


• had depth perception (eyes close together in front of face)


• eye-hand coordination


• parents cared for their offspring

The 2 Major Primate Groups:

Prosimians

• oldest


• EX- lemurs, lorises, pottos, tarsiers

Anthropoids

• 
  EX-monkeys, apes, humans


• New World monkeys


• in the Americas


• arboreal


• prehensile tails-could swing by tails and grab things with them unlike dogs or cats, it functioned as an extra appendage


• Old World monkeys


• mostly ground dwellers


• EX- baboons-


• -Prehensile tail, New World

Human Ancestors

• closest anthropoid relatives=apes
• gibbons, orangutans, gorillas, chimps
• apes today live in tropical regions of Old World
• Humans
• young twig on vertebrate branch
• chimps and humans diverged from common ancestor 5-7 million yrs. ago

• Our ancestors are not modern apes and chimps; we diverged on a different branch than they did, but we both evolved from a common ancestor
• they are more like our cousins than anything else

• Human evolution is not a series of steps leading directly from an anthropoid ancestor to Homo sapiens; other groups have traveled to dead ends and died off
• Many different human species coexisted
• We are a subspecies of Homo sapiens

• Human characteristics did not evolve at the same time
• They evolved at different rates
• Bipedalism-walking on two feet, led the way
• We had some ancestors who walked on two feet and upright, but they still had ape-sized brains

Kinds of Hominids

Australopithecus-walked African savanna, came before Homo genus:

• A. afarensis
• early species
• bipedal
• a skull was found that was about 3.9 million yrs. old. It had a vertical backbone which provided evidence that upright posture is at least that old
• Lucy-very complete skeleton of A. afarensis, female, 3ft tall, 3.2 million yrs. old
• footprints also found, bipedal footprints in Africa, 3.7 million yrs. old
• bipedalism is a very old trait
• Australopithecus went extinct about 1.4 million yrs. ago

Homework!!

Lab 32-due Monday

Up pgs. 69-70, read and questions

Next scribe:

Aliza!! :)

2/8/11 Class Overview

Notes:

How to tell geologic time using fossils

Macroevolution - large scale evolution (one species turns into another)
Microevolution - minor evolutionary changes

-Fossils in sedimentary rocks show that macroevolution has happened
-Earth's layers show a record of life
-Layers of sediment/fossil dating don't tell exact age... only ballpark/relative
-Layers closer to Earth's surface are youngest
-Deeper down low are older

4 Eras of Time: Precambrian, Paleozoic, Mesozoic, Cenezoic

Radiometric Dating
-Measure how much radiation a fossil releases as they break down
-The amount of radiation as well as level of decay give you exact years
-Half-Life=the amount of time it takes for half of a fossil to radioactively decay
--So if a bat fossil would normally take 100 years to decay, its half-life is 50 years
--Think of the decay period (100 years) as the fossil's life, half of it is 50
-To date very old fossils, paleontologists simply use isotopes with longer half-lives
-Isotope=an atom (like the M&M's in our lab today) with uneven numbers of protons/neutrons

Continental Drift: Pangaea
-The idea that all land in the world used to be one huge piece of land
-It broke apart slowly into the separate pieces of today
-Still breaking apart.... 2 cm/year (Thanks Nick)
-Impacts of land break=extinctions, species isolation according to continents
-Plate boundaries=place where 2 plates meet
-Earthquakes occur at plate boundaries





In-Class Lab: M&M's

Purpose: To learn how radiometric dating and radioactive decay work

-The M&M's represented atoms that were radioactively decaying
-We took 100 and kept decaying them randomly by spreading them out and removing the ones that had no "M" inscribed on top. The removal represented decay~
-Once they decayed to around 50, the half-life was found by seeing how much time it took to get to 50 because half-life is a time period

Quiz on all evolution tomorrow.

Next Scribe: Bridget

February 7th

CJ P.
Took notes today. Lots o' notes.
HW: 39-43 in UP. Read ch. 1, 13, 14, 15, 17. Quiz tomorrow
Notes pages 1-11 in 7B packet.

LIFE ON ANCIENT EARTH
Earth theories on life development:
1. BIG BANG - great big explosion and condensed forming atoms.
4 conditions necessary for chemical evolution:
1. No free oxygen. So no mammals.
2. Energy - built up by storms, volcanoes, and UV radiation.
3. Chemicals
4. Time.

OPARIN HYPOTHESIS:
Simulated mini big bang. mini bang.
Found monomers which make polymers and amino acids and building blocks and and and RNA and DNA bases!

HOW DID LIFE FORM?!
1. life from non life.
2. life from life
3. Earth's new compounds.

EARTH SOUP = primordial.

Stages of origin of life:
1. Synthesis from abiotic chemicals.
2. linked monomers to make polymers (amino acids)
3. Origin of SELF replicating
4. Formation of pre-cells using monomers and polymers to form precells (no nuclei)
THESE CAME FIRST: Single cell, anaerobic, asexual, heterotrophic.

cell theory:
Cells are building blocks of life, cells come from other cells, all living things contain cells.

How did species evolve? From natural selection! Nature selected the fittest.

MACROEVOLUTION:
Speciation: creating new species. NONBRANCHING vs. BRANCHING
NONBRANCHING turns into different species
BRANCHING creates a new species and keeps the original ancestor as well.

SPECIES create FERTILE offspring!
REPRODUCTIVE BARRIERS
PREZYGOTIC BARRIERS
1. Temporal isolation ---> TIME
2. Habitat isolation ----> some species live in winter, some in fall
3. Behavioral isolation ---> species must understand mating rituals, if not, no game.
4. Mechanical isolation ----> sex organ must work.
5. Gametic isolation ----> sex organs work together, but gametes do not work.

POSTZYGOTIC BARRIERS
1. Hybrid inuiability---->offspring dies early in life
2. Hybrid sterility ----> offspring lives but is infertile/sterile

allopatric - other country. Some organisms are physically separated making it impossible for them to mate and produce new species
sympatric - together. new species live amongst parent species.

polyploidy - sudden speciation



My name is CJ and thank you for joining us on this week's episode of Honors Biology Period Three: THE BLOG.

Back to you, James (aka next scribe)

STUDY, QUIZ TOMOMO.

Feb 4

Hardy-Weinberg
important things to remember:

Punnett Squares
-know where to place dominant homozygous, heterozygous, recessive homozygous











p= dominant
q= recessive

p+q=1
p^2 + 2pq + q^2 = 1

If you know p, then you know q (and vice versa)

know the difference between frequency and percentage

know the difference between finding the frequency/percentage of a gene (p/q) and population (2pq/p^2/q^2)

read the question carefully- the given info might not be what you think at first
go back to genetics notes if you forgot recessive/ dominant diseases

Notes
Vocab
-microevolution
-genetic drift:
-bottleneck/founder effect
-gene pool
-gene flow
-mutations
-natural selection:
-directional, diversifying, stabilizing
-darwinian fitness

Next scribe - CJ

Feb 1st

Today, we went over answers to UP pgs. 17A-E and notes.

WHAT NOTES???

Modern synthesis: the fusion of genetics with biology

Modern synthesis is a study of variations in populations caused by mutations and sexual recombination.

Population: group of SAME SPIECIES living in same area at same time (Important!)

Gene Pools: all of the alleles in all the individuals making up a population (how many big and small alleles)

Allele: form a trait

Ex: Wildflower with only two varieties-

Red flowers = R & white flowers = r

Suppose 80% or .8 of all flowers in the gene pool have the R allele.

p = relative frequency (how common something is) of the dominant allele (R), so p = .8

q = frequency of the recessive allele (r), so q = .2

YOU MAY BE THINKING, “BUT WHY?”

Since there are only two alleles for flower color, then p+q=1 (MEMORIZE FOR TEST)!

Now that we know the formula, we can find the frequencies of the different genotypes in the population IF the gene pool is completely stable (non-evolving).

Meaning, no one can leave or join the population.

This is called the Hardy-Weinberg equilibrium.

G.H. Hardy questioned, “How can both dominant and recessive alleles remain in populations? Why don’t dominants simply drive out recessives?”

It was discovered that genetic recombination does not by itself change the overall composition of the gene pool. They examined the behavior of alleles in an idealized population in which five conditions hold:

1. No mutations occur

2. No net movement of individuals in or out of the population

3. Population is large enough

4. Mating is random

5. All alleles are equally viable (no natural selection)

• Ex: Dwarfism -> Aa = Dwarf aa = normal AA = too much dwarfism in you, you can’t survive

This ideal environment is hard to find.

Now, back to the wildflower problem!

What’s the probability of producing an RR individual by “drawing” two R alleles from the pool of gametes?

R sperm x R egg (p x p) -> .8 x .8 = .64, or 64% of the plants in the population will have the RR genotype.

Well then, what is the frequency of rr individuals in the population?

r x r (q x q) -> .2 x .2 = .04, or 4% of the plants in the population will have the rr genotype.

What is the frequency of Rr in the population?

Rr + rR, or 2pq

2 (.8 x.2) = .32, or 32% are Rr with red flowers.

General formula: p^2+2pq+q^2=1 (MEMORIZE)!

You can use a Punnett Square to solve the problem as well.



Tonight’s homework:  UP pgs. 31-36 due Thursday

Next Scribe: Christine K.

Justin A.

1/26/11

We started off the day by turning UP pg 11 and 12. Next we filled out a sheet about the science class we are going to take next year. Then we began notes.

Notes:

• All life is connected
• Evolution is cause of today's diversity.
• Charles Darwin came up with the idea. He wrote "The origins of Species" in 1859.
• 2 main points in book:1. "decent with modification"(this means every descendent is a little different. 2. the mechanism for evolution is "natural selection"
• Darwin loved nature and traveled world in HMS Beagle." He observed species on different islands
• saw variety of finches in the Galapagos Islands.
• After many generations, 2 populations could become dissimilar enough to be separate. (called divergent evolution)
• Darwin observed the finches' beaks and color.
• 
• Natural selection- 3 main points:

1. Overproduction- leads to struggle for existence among individuals of a population.
2. Individuals in a population vary in traits, no 2 are alike.
3. Individuals with best traits to survive leave greatest number of surviving offsprings.

• Nature decides what traits are most fit.
• Adaption is accumulation of favorable variation in a population over time.
• Darwin looked at Artificial Selection- Humans modify species to get best traits.
• In Artificial selection. humans change trait, not nature.
• natural selection today, i.e.= Pesticide- now some insects are immune to pesticide.
• Camouflage is an example of evolutionary adaption. (mantids)

• Evolution- 2 modern definitions:

1. genetic composition changes over time
2. all life descended from common ancestor

• Scientist during Darwin's time thought earth was young, and that Darwin's idea was radical
• Anizimander- Greek philosopher who though simpler forms of life preceded more complex life.
• Aristotle- Greek philosopher thought species were fixed and didnt evolve.
• Buffon- studied fossils. Said Earth is mush older. Said species in fossils were ancient versions of modern species.
• Lamarck- said the life evolves through adaptation.
• He said "Inheritance of Aquired Characteristics" (not using a body part would cause offspring to be born without that body part.
• Lyell-said ancient earth was sculpted by geologic process. (earthquake and mountains)
• Graualism principle.
• Wallace-developed concept of natural selection. Had same idea as Darwin but Darwin published his ideas before Wallace did.
• fossils- preserved remnants of impressions left by organisms that lived in the past.
• Younger strata are on top of the older ones. Level reveals "relative age"
• Fish like vertebrats are oldest, then amphibians, then reptiles, then mammals and birds.
• Paleontologist- scientise who studies fossils.

Homework: UP pg 5, E.C. pg 6 and/or M&M.

Next scribe: Katie