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Transcript of Heredity unit
DNA,Mendel and Genetics
What controls traits?
Types of Inheritance
the passing of traits from parent to offspring.
the passing on of physical or mental characteristics from one individual to another.
Mendel and his peas.
- Friar in the 1800s
- because of his experiments with the pea plants he is considered the father of genetics.
When Mendel bred plants with purple flowers together they produced only purple flowers.
When Mendel bred plants with white flowers together, they produced only white flowers.
When Mendel bred plants with white flowers together with purple flowers what do you think happened?
2. Gregor Mendel discovered that traits (or genes) are passed from parent to offspring.
a. parent: an organism from which younger ones are produced from
b. offspring - seeds, babies, eggs, etc.
First, lets get the definition of a hybrid.
A hybrid is the offspring of two animals or plants with different forms of the same trait.
So for example, if a person with 2 brown eyed traits were to have a baby with an individual with two blue eye traits, this baby could be considered a hybrid for this trait.
a. Dominant: the trait that will appear no matter what other genes are present.
b. Recessive: the trait that is in DNA, but not expressed or seen unless all genes for that trait are the same. (example: blue eyes, or blonde hair)
4. Dominant and Recessive Traits
Today this seems obvious to us as kids can look a lot like their parents with traits from either side.
Each trait that you have either visible or not can be traced back to your genes. A dominant trait can allow a certain trait to be expressed such as dark eyes.
NO, Not those kind of jeans! Genes! Your genetic code!
However, if a dominant trait is not present from the genetic make up of an individual then a recessive trait can be expressed.
A. What controls traits?
In humans we have 23 pairs. Each pair consists of two chromosomes one from each parent.
Each tiny message on your chromosomes is called a gene.
Each gene can have different forms called alleles.
7. Alleles: alleles are different forms of a gene.
In Mendel's pea experiments the hybrid pea plants had two alleles for flower color. One for purple and the other for white.
- a third of a piece of paper
- a pair of scissors
- a marker or colored pencil
It's time to create a graphic organizer.
Step 1: Fold the paper into thirds.
Step 2: On the outside flap write: chromosomes hold genetic information and draw a picture of a chromosome.
Step 3: On the inside flap write: genes hold specific genetic information for specific traits and draw a picture of a gene on a chromosome.
Step 4: In the middle of the paper write: each gene can have different forms called alleles.
When you have decorated your graphic organizer to help you remember this information, put glue on the back middle. Glue this into your notes in the space provided.
In your notes we are going to build a graphic organizer to help up remember this information.
Phenotype Genotype What's the Difference?
explains just what you will see or have.
Time for Dog Breeding
Practice with Spongebob Genetics
Making a graphic organizer...
Take one piece of paper and fold it almost in half so that it overlaps the far edge by one inch.
Take another piece and fold it almost in half, but make it overlap by two inches.
Put the two papers together so that they fit inside one another and you get four flaps facing you.
Staple them at the fold.
On the outside top flap write:
On the next flap write:
Types of Dominance
Then on the inside make three columns and place in the columns:
dominant trait will be expressed
ex. Mendel's Pea plants
when the alleles of a gene mix together like paint.
ex: straight ear allele of a dog mixes with floppy ear allele to make a medium floppy ear.
both alleles can be observed in a phenotype
ex: a red haired cow and a white haired cow produce a cow with both red and white hairs
On the next flap write:
traits can be determined by more than just two alleles.
ex: blood type
multiple genes determine the phenotype of trait or one trait can be affected by multiple genes.
ex. skin color, eye color, height in humans
On the last flap write:
DNA & Mutants
1. Every time a cell divides it creates new copies of DNA.
D. New Cells & DNA
1. Genes are sections of
2. Chromosomes are made up of
proteins and deoxyribonucleic
(dee AHK sih ri boh noo klee ihk) acid or
3. DNA is
an organism's genetic material.
The Human Recipe Book
DNA is like a cookbook because it is a long
set of instructions that your body reads in order to make you.
The entirety of the DNA code is made up of only four nucleotides. They are repeated and replicated over an over in different orders in a structure called a double helix.
These nucleotides are like the alphabet of DNA.
They fit together like a puzzle with adenine or A's only connecting to thymine or T's. Cytosine or C's will only pair up with guanine or G's.
This long stream of instructions lets a cell...
know how and what to build.
When a cell needs to divide to make a new cell, it makes new components including more DNA.
During the process of replication the double helix of the DNA zips open and splits apart like a zipper and replicates itself.
It can do this because each side of the DNA has a special code. Remember A's only connect to T's, and C's only connect to G's.
1. Sometimes during replication genes will mutate (change).
a. Mutation: a change in the genetic code (examples: down syndrome; blue eyes, light skin, red hair, syndromes)
Sometimes mistakes are made. Most of the time these mistakes will be fixed or repaired before the DNA seals itself up. But sometimes mutations are made.
Often mutations are not harmful. Sometimes they can benefit an organism. But in some cases they can be detrimental.
2. Mutations are only passed on if they occur in the sex cells (sperm & egg) of an individual and are passed to offspring.
4. Genetic disorders from mutations in the cells.
a) Cystic fibrosis
cause: a defective gene
result: causes mucus build up in lungs
b) Williams syndrome
cause: deletion of genes
result: developmental delays, facial differences, and cheery demeanor. These individuals are at ease with strangers.
c) Down syndrome
cause: additional chromosome either part or all of the 21 chromosome
result: mental retardation and sometimes also restrictions on physical growth.
d) Sickle-cell anemia
cause: recessive trait blood disorder
result: oddly shaped blood cells limiting ability to carry oxygen and nutrients; usually results in limited life span.
So how do we get all this DNA anyhow?
So how do we get all of this DNA anyhow?
As humans we get it from inheritance from our parents.
F. Inheritance: the passing of traits from generation to generation.
1.All of your inherited traits come from a combination of genes from your mother and father.
2. This is done through a gene exchange known as
for many organisms like humans, plants, animals, etc.
a) In sexual reproduction, chromosomes mix and match the traits they have. This lets every individual be original.
Acquired traits are a bit different.
1. Acquired traits: characteristic that an individual gets during their lifetime.
Once people use to think that traits were acquired and could be passed down to their children.
a) An acquired trait is not inherited by the offspring from the parents; You can't genetically pass on your learned piano skills to your offspring.
Acquired vs Inherited
sense of humor
ability to play volleyball
1. Sexual reproduction and asexual reproduction both produce offspring from a parent.
a) Completely different species can't produce offspring.
i) Example: a snake cannot be bred with a lizard.
Their DNA is too incompatible to make an offspring (aka baby).
2. During sexual reproduction process, genetic materials from
cells (sperm & egg/ pollen and ovule) combine, producing an offspring.
3. Advantages of Sexual Reproduction
a) Genetic Variation – individuals are genetically unique with slight variations.
i) These variations could be an advantage to fight off disease and evolve
Ex. sickle cell anemia
b) Breeding – helps to produce plants or animals with specifically desired traits.
i) Ex. The selective breeding of grasses is what has given us the corn we eat today.
c) All children are different from their parents allowing for diversity.
1. takes time and energy
waiting until maturity
can't have offspring if you can't find a mate
2. Possible exposure to sexually transmitted diseases
3. Fertilization cannot take place during pregnancy
a) involves specialized sex cells
b) union of a female and male individuals or parts
5. Sexual Reproduction Involves
In sexual reproduction process, genes swap alleles and the cell divides through meiosis to become four unique specialized sex cells.
a) Sexual reproduction always involves two individuals contributing genetic code.
6. What kinds of organisms have sexual reproduction?
Begins with either a male plant or female plant;
Male produces sperm - Female produces an egg
When it rains the male plant releases its sperm and the sperm either splashes onto the female plant or it has to swim to the female plant to fertilize the eggs.
After fertilization this produces a sporophyte which grows thousands of spores which are released in the wind and will germinate when it lands on the soil.
They do not have seeds, but they do have spores. The gametophyte of the fern produces both eggs and sperm cells in one plant. Like the mosses the sperm is released during rain storm and swims to nearby eggs to fertilize them.
When this occurs the plant grows into the fern plant and produces spores that burst and spread to new soils to start the cycle again.
Grasses – bamboo, your lawn, wheat plants or corn plants, have a male and female parts as well. The male pollen relies on the wind to get it to the ovules (like eggs) to be fertilized.
Cones from conifers or gymnosperms also rely on the winds to carry their pollen to the female parts of other trees.
Because of this reliance on chance, these plants that use the wind to fertilize their offspring tend to need to produce tons of pollen just to ensure that their eggs become fertile.
Also have pollen and
, but flowers communicate with animals and lure them in with a tasty treat.
The insect or animal gets nourishment and the planet gets pollination. Because the animals come to them, they don't need to take all the energy producing so much pollen.
Once fertilized, the plant will produce seeds.
Animals that need to fertilized their eggs in water will tend to have an external sexual experience such as frogs, fish, coral, etc. The female will lay her eggs in the water and the male will excrete swimming sperm to fertile them.
Most animals (sperm and egg)
Animals that do not go to the water like birds, mammals, some insects, etc. use an internal fertilization where a male body part will enter the female (in most cases) and inject sperm into the female
which swims to the
egg for fertilization.
Animals & Sexual Reproduction
7. Types of Organisms that do Sexual Reproduction:
In sexual reproduction, an offspring inherits half of their DNA from each parent resulting in genetic variation- difference.
I. Asexual reproduction one parent organism produces offspring without meiosis and fertilization.
1) Because asexual organisms inherit ALL of their DNA from just one parent, they are all genetically identical to each other and to their parent. They are essentially clones or replications.
Time to make another graphic organizer! This time just draw it in.
D. Types of Asexual Reproduction
a) fission: cell division in prokaryotes (like bacteria) that forms two genetically identical cells.
b) Mitotic cell division: eukaryotes reproducing from mitotic cell division.
(there is one and then there are two)
c) Budding: a new organism grows by mitosis and cell division on the body of its parent (multicellular)
d) Animal regeneration: an offspring grows from a piece of its parent; also production of new parts.
e) vegetative reproduction: a form of asexual reproduction in which offspring grow form a part of a parent plant.
f) Cloning: laboratory procedure creating identical twins from cells taken from a multicellular organism.
2. Asexual Reproduction Advantages:
a) reproduction without finding a mate
b) reproduce rapidly and large number of offspring
a) offspring are genetically identical to their parent (lower survival rate)
b) genetic changes or mutations can be passed on to every offspring
Bacteria – some can divide and replicate once every 9.8 minutes.
Fungus – can produce both asexual and sexual spores; asexual spores are pieces of the fungus that drop of or are ejected off from the reproductive sections of the fungus are carried off by the wind and become a genetically identical new offspring;
hydra – live in unpolluted fresh water places like ponds and lakes. Interesting because they appear not to age or die due to their regenerative ability. They grow buds that grow into miniature adults. Then they break away and become a genetically identically new offspring.
cuttings from some plants - Vegetative regeneration
Rare animal asexual reproductions
4. Organisms that have asexual reproduction:
a. bacteria (fission)
b. amoeba (mitotic cell division)
c. hydra (budding)
d. fungus (vegetative reproduction)
e. sea stars (animal regeneration)
f. planaria (fission & animal regen)
Checkered whiptail lizard is an all female species of lizard that can lay eggs and produce viable genetically identical offspring.
A couple types of stick-bugs are asexual producing eggs which hatch into genetically identical female offspring to that of the mother.
Honey Bees - Drones are male honey bees. They develop from eggs that have not been fertilized, and they cannot sting, since the worker bee's stinger is a modified ovipositor (an egg laying organ). Drones carry only one type of allele because they are haploid (containing only one set of chromosomes) from the mother. -Wikipedia
What Mendel created and discovered is now called a
1. What you will look like, what eye color, animal, skin color, is all determined by your
6. Gene: A gene is a section on a chromosome that has genetic information for one trait.
6. On your genes you have two messages for every characteristic of what makes you, you! Only one message gets expressed or
consists of two
that tells you all of the messages or genes you have for that trait.
1. Our genetics are inherited from our parents.
There are many different types of inheritance that allow us look. sound, and even walk the way we do. These all combine in different ways.
3. Mutations in bacteria and viruses causes resistant and stronger pathogens. Bacteria that mutate can become immune to antibiotics.
Sometimes these negative mutations can result in genetic disorders.
G. Acquired traits vs. inherited traits.
b) examples of acquired traits:
Let's come up with some for our notes!
2. Inherited traits
are passed down from your family in your DNA.
You have these traits whether you are raised by your parents or are adopted.
inherited trait cannot be changed or altered by your will.
b) Examples of inherited traits:
Let's come up with another list for our notes!
b) This involves a male and female gamete
or gamete from hermaphrodites.
i) Gametes are sex cells of organisms. In humans they are the egg and the sperm.
c) Each gamete contains just one half of the genetic code or DNA
d) In sexual reproduction the two gametes, the male and female, come together and produce an offspring.
The prefix a means no or not. So asexual reproduction means not sexual.
smaller than half an inch
Dolly the sheep
July 1996 - Feb 2003
First multicellular organisms to be cloned from an adult cell.
Planaria live in salt and fresh water. Is a flatworm that if split in two can become two organisms. Some are both asexual and sexual (hermaphrodite). Asexual they detach their tails and it grows a new planaria while the parent regrows its tail back.
IX. Lesson 8
X. Lesson 9
Any physical body part, behavior, or mental ability that increases an animal's ability to survive in its environment.
B. Examples of adaptations:
1) Light colored leaves (desert plant)
2) White fur in the arctic
7) Infrared sensing
8) Warm Blooded
Adaptation of Birds
1) the close resemblance of an animal or plant (or part of one) to another animal, plant, or inanimate object.
2. mimicry can be looks, sound, or movement.
A. Evolution: the gradual change of a species over time through multiple generations.
Can be observed
(example: bacteria, flies, and even the human race)
Blue and green eyes have only been around for several thousand years.
Interesting fact: only 2% of the world's population is thought to have green eyes; Celtic or German decent.
Evolution has no stopping point.
Nor does it have end goals.
Chimps if given enough time WILL NOT EVOLVE INTO HUMANS!!!
Evolution is simply change.
Man did not come from chimps.
Chimps are a new evolutionary organism.
Chimps and man evolved from a common ancestor.
We are not them...
They are not us.....
We will never be them......
They will never be us.
B. Evolution occurs through diversity of offspring and mutations.
1. Natural selection: organisms better adapted to their environment tend to survive and produce more offspring ("survival of the fittest")
2. Artificial selection (man caused): intentional breeding of plants or animals to bring about desired traits
C. Natural Selection
Individuals with traits better suited for their environment are more likely to pass their genes on. (cuz they live longer and make more babies)
animals that blend in
strong male lion gets all the girls
insects with long tongues
drought resistant plants
D. Artificial Selection
Artificial selection (aka selective breeding) humans breed animals and plants for specific traits
breeding to get larger fruits and veggies
more meat or food production
A. DNA - deoxyribonuecleic acid
1. DNA - all life from bacteria to humans has DNA
2. DNA is the code for life; it is the instructions for making any life form.
3. DNA is made up of different molecules and is store in structures called chromosomes;
a. Chromosomes are stored inside the nuclei of most cells.
Each organism has a specific set of codes and a different amount of chromosomes. Humans have 46 chromosomes.
Building a DNA Strand
1. Genetics: the study of how traits are passed from parents to offspring.
What is a trait?
3. Trait: a specific quality or characteristic; example: blonde hair, height
5. Gene: a section of DNA that determines a specific trait that is transferred from a parent to offspring
DNA is bound up in structures called ____?
& Gummy Bear LAB
Mitosis & Meiosis
2. This process of division is called MITOSIS
a. During mitosis a cell makes a copy of DNA and divides into two cells each with just one set of DNA
Mitosis is useful for:
development and growth
and some asexual organisms reproduction
Without mitosis your hair wouldn't grow, you'd have no new blood, in fact you would have never made it past a fertilized egg.
4 Phases of Mitosis
Nuclear membrane breaks apart
Chromosomes condense and form like pairs
4 Phases of Mitosis
like chromosomes line up along the center of the cell
Spindle fibers attach to each chromosome
4 Phases of Mitosis
like chromosomes separate and are pulled to opposite ends of the cell.
4 Phases of Mitosis
Nuclear membrane forms around each set of chromosomes.
The cytoplasm divides, forming two daughter cells (or in plants a cell wall forms)
...makes another me
3. Meiosis: cells divide to create four cells with half the DNA. Each cell has different DNA!
a) Only happens in sex cells (sperm, egg, ovule, pollen, etc.)
b) Sex cells divide into two cells, scramble the alleles for genes;
c) then both cells split into four cells that contain a unique set of half of the genetic code.
Why purpose would scrambling the genes be for?
Why do the cell only contain half of the genetic code (DNA)?
Compare Mitosis and Meiosis
Number of chromosomes in parent cell
Type of parent cell
Number of divisions of nucleus
Number of daughter cells produced
Chromosome number in daughter cells
or pairs of chromosomes
diploid or pairs of chromosomes
pairs of chromosomes
half of a pair of chromosomes
growth, cell repair, some types of reproduction
forms sperm and egg cells
b. Mitosis is used for growing new cells like bone, muscle, blood, etc.
H. Sexual reproduction vs. asexual reproduction.
The birdog is a lie!
1) Behavioral adaptation: something you do that increases your chance for survival (putting on a blanket when cold)
2) Physical adaptation: Body structure or coloring that allows for an advantage; (fast twitch muscles letting you run faster; camouflage)
C. Camouflage: hide or disguise the presence of (a person, animal, or object)