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

Regents Biology

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?

Regents Biology

Inheritance of chromosomes Meiosis = making sex cells (egg and sperm) Egg + sperm zygote

egg

sperm

zygote

fertilizationmitosis &

development

meiosis

Regents Biology

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?)

Regents Biology

Effect of genes Genes come in different versions

brown vs. blue eyes brown vs. blonde hair alleles

Regents Biology

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

Regents Biology

Genes affect what you look like

XBBbb

Bb Bb Bb Bb

Where did the blue eyes go??

Regents Biology

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??

Regents Biology

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

Regents Biology

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)

Regents Biology

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!

Regents Biology

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

Regents Biology

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

Regents Biology

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

Regents Biology

Traits Inventory Let’s check some of your traits and

alleles you have

Traits Inventory Packet

Regents Biology

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