regents biology welcome to semester 2 topics genetics classification viruses/bacteria very brief...
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Regents Biology
Welcome to Semester 2Topics Genetics Classification Viruses/Bacteria Very brief – plants and fungi Animal Development Animal Phyla Human Body
Fresh Start for your Semester 2 Grade Full effort, come in for help, get homework
done, take notes, study for tests…set goals for a higher grade
Regents Biology
Agendas Out Plan for this week – write down your
homework (use your agendas this semester – they help!)
Semester 1 Final Exam – if you want to go through the test, you may come in on your own time to check your answers (you will be given key to check with)
Regents Biology
Zebra Like our fingerprints – no two
patterns are exactly the same 3 different species – each
species does have a general pattern
Stripes distort distance at dawn and dusk – tricks predators
Social animals – graze together, groom each other
Some herds can have over a thousand members
Look-out for each other and protect the wounded of their group
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Cucumber Genetics In about 2 weeks we will be tasting cucumber
cotyledons to determine whether they are the bitter or non-bitter variety – then we will collect data to determine the genes that code for bitter/non-bitter and their frequency
Today, you will be planting 1 seed in a pot of soil – don’t place seed too deep in soil
Water your plant Label your name and hour on the pot/cup WASH HANDS AFTER PLANTING
2006-2007 Regents Biology
Genetics *study of passing on of characteristics from parents to offspring
Why do we look the way we do?
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Inheritance of chromosomes Meiosis = making sex cells (egg and sperm) Egg + sperm zygote
egg
sperm
zygote
fertilizationmitosis &
development
meiosis
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Inheritance of genes On the chromosomes passed from
Mom & Dad to offspring are genes may be same information may be different information
eye color(blue or brown?)
eye color(blue or brown?)
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Effect of genes Genes come in different versions
brown vs. blue eyes brown vs. blonde hair alleles
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What did we show here? Genes come in “versions”
brown vs. blue eye color alleles
Alleles are inherited separately from each parent brown & blue eye colors are separate &
do not blend either have brown or blue eyes, not a blend
Some alleles mask others brown eye color masked blue
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Genes affect what you look like
XBBbb
Bb Bb Bb Bb
Where did the blue eyes go??
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Genes affect what you look like…
XBbbb
Bb Bb bb bb
Why did the blue eyes stay??
Regents Biology
Genes affect what you look like…
XBbBb
BB or Bb BB or Bb BB or Bb bb
Where did the blue eyes come from??
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How does this work?
eye color(brown?)
hair color
hair color
eye color
(blue?)
Paired chromosomes have same kind of genes but may be different alleles
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Yunnan Snub-nosed Monkeys
Old world monkeys Live in small part of China
mountains, and a small colony is found in Tibet
Endangered Specialist feeders – eat only
lichens growing on the bark of pine trees
Named from short, stumpy nose Live high up in mountain forests,
up to 4700 meters up! World’s highest living non-human
primates Live in groups of 20-60 Little is known about them – hard
to study! Not discovered until the 1990’s!
Regents Biology
The Father of Genetics Gregor Mendel – first person to predict
how traits pass between generations Studied pea plants Self-pollination and cross-pollination Studies 1 trait at a time - Monohybrid Studies short vs. tall plants over several
generations, then also studies other plant traits separately
Regents Biology
Generations P1 = Parent
F1 = First Filial (first set of offspring)
F2 = Second Filial (second set of offspring)
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Extending Mendelian genetics Mendel worked with a simple system
peas are genetically simple most traits are controlled by single gene each gene has only 2 version
1 completely dominant (A) 1 recessive (a)
But its usually not that simple!
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Traits are inherited as separate units
1 from Mom
1 from Dad
For each trait, an organism inherits 2 copies of a gene, 1 from each parent a diploid organism inherits
1 set of chromosomes from each parent diploid = 2 sets of chromosomes Sex cells are haploid (1 set of
chromosomes)
homologous chromosomes
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Making gametes
BB = brown eyesbb = blues eyesBb = brown eyes
BB
bb
Bb
brown is dominant over blue
blue is recessive to brown
Remember meiosis!
B
B
b
b
B
b
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How do we say it?
BB = brown eyesbb = blues eyes
Bb = brown eyes
2 of the sameHomozygous
2 differentHeterozygous
BB
B
B
bb
b
b
Bb
B
b
homozygous dominanthomozygous recessive
Regents Biology
Genetics vs. appearance There can be a difference between
how an organism looks & its geneticsappearance or trait = phenotype
brown eyes vs. blue eyesgenetic makeup = genotype
BB, Bb, bb
2 people can have the same appearance but have different genetics: BB vs Bb
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Traits Inventory Let’s check some of your traits and
alleles you have
Traits Inventory Packet
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Punnett squares (predict possible offspring)
Bb x Bbmale / sperm
fem
ale
/ eg
gs
X
BB
Bb bb
BbB
b
B b
Regents Biology
Genetics vs. appearance
eye color(brown)
eye color
(brown)
eye color(blue)
eye color
(brown)
vs.
BB
B
BBb
B
b
How were these brown eyes made?How were these brown eyes made?
2005-2006 Regents Biology
Woof! Woof!Any Questions?
2005-2006Regents Biology
Dog Genes and Pea Pod WS Let’s practice what we just went over! Let’s do one Punnet Square Together –
then take 8-10 minutes to complete the rest of the worksheet (both sides)
2005-2006Regents Biology
Monohybrid Cross Worksheet Due Thursday – you will have some
time to work tomorrow if you finish lab early