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GENETICS AND ADAPTATIONS
BUTTERFLIES Count how many butterflies you can
spot on the wall
Count how many butterflies you can spot on the floor
INHERITED VS. ACQUIRED TRAITS What is an acquired trait?
A trait that an organism acquires or gains over its lifetime. It cannot be passed on to its offspring. Like the ability a monkey has to peel a banana.
What is an inherited trait? A trait that is passed to offspring because of
genetic inheritance. Could be good or bad for the organism.
INHERITED TRAITS What are some examples of traits that
make an organism MORE suited to its environment?
What are some examples of traits that make an organism LESS suited to its environment?
INHERITED OR ACQUIRED? Blue eyes
Dog’s short fur
Broken arm
Blonde hair
A Cold
Sun tan
Colorblindness
Ability to roll tongue
Love of music
Ability to do math well
TOOTHPICK ACTIVITY In your group of 3, time each person for
10 seconds while they pick up toothpicks one by one.
Make a chart in your notes of how many toothpicks of each color each person picked up.Person Brown Red Yellow
Leonardo
Donatello
Michaelangelo
HOMEWORK Write down 5 acquired traits.
Write down 5 traits that you have inherited from your parents.
LAMARCK When environments changed, organisms
had to change their behavior to survive. If they began to use an organ more than they had in the past, it would increase in its lifetime. If a giraffe stretched its neck for leaves, for example, a "nervous fluid" would flow into its neck and make it longer. Its offspring would inherit the longer neck, and continued stretching would make it longer still over several generations. Meanwhile organs that organisms stopped using would shrink.
Is this true?
HOW ARE TRAITS PASSED ON? Two ways to inherit traits. Most
organisms reproduce with one or the other, not both.Asexual reproductionSexual reproduction
Both use genetic information (DNA) to create offspring
ASEXUAL REPRODUCTION The DNA of the parent is the same as
the offspring.
Any genetic mutation (whether good or bad) will be passed onto the offspring.
Mitosis
BACTERIA
SOME PLANTS
ALGAE
MARINE LIFE
HYDRA
PLANERIA
FUNGI
SEXUAL REPRODUCTION A better system for producing genetic
variation and therefore “fitness” for an environment
½ of the DNA from one parent and ½ from the other parent
Meiosis
SEXUAL REPRODUCTION Advantages
More opportunity for mutationsMore DNA combinations
DisadvantagesSometimes takes longerSome bad genes are still possible
MAMMALS
BIRDS
FISH
REPTILES
DNA Double ½ genes on one side ½ genes on other side Sex cells have ½ Mutation is a change in the DNA. Can be goodor bad.
MITOSIS One cell splits into 2 cells
Makes an exact copy of itself
All the DNA, traits are exactly the same
MEIOSIS Cell divides and makes 4 copies.
Each new cell gets ½ the DNA of the first cell.
Used in sexual reproduction to make eggs, pollen, etc.
DNA ACTIVITY Read pg C97-103 as a class.
Make an example of an offspring’s DNA in asexual and sexual reproduction.
Follow the example on the board.
LIGERS
• Lion and tiger mixed together• Half of its DNA is from lion, half
from tiger• Has traits of both animals• Does not occur in nature
OTHER HYBRIDS
Splake- hybrid of male brook trout and female lake trout
Africanized honey bee- African and European bees, “killer bees”
Beefalo-cattle and bison
Zebroid-zebra and horse
ACTIVITY
• You need to create your own hybrid!• Draw a picture of what your hybrid
would look like• List the traits it would get from each
of its parents• List the advantages and
disadvantages it would have in the wild
• DUE AT THE END OF CLASS!!!
WORDS YOU NEED TO KNOW Allele: Different forms of a gene
Homozygous: the same alleles (either both are dominant or both are recessive).
Heterozygous: different alleles
Phenotype: what an organism LOOKS like
Genotype: what an organism’s GENES say
DOMINANT ALLELES Dominant alleles occur on sections of
DNA that code for a particular trait.
If a dominant allele is present, then the organism is going to have the phenotype for that trait
Example: If you have the gene for free ear lobes, then
you will have free ear lobes.
RECESSIVE ALLELES Recessive alleles occur on DNA sections
where BOTH strands of the DNA must have the recessive allele in order for the recessive trait to be shown or expressed.
Example: If you have 1 gene for connected ear lobes,
and 1 gene for free ear lobes, then you will have free ear lobes
If you have 2 genes for connected ear lobes, then you will have connected ear lobes
HOW TO REPRESENT GENES In “genetic writing”, dominant
traits/alleles are represented by capital letters, such as “B”
Recessive traits/alleles are represented by lower case letters, such as “b”
BB=homozygous dominant bb=homozygous recessive Bb=heterozygous
CODOMINANCE AND INCOMPLETE DOMINANCE Co-dominance is when there is more
than one dominant allele, as well as a recessive alleleBlood type: A, AB, B, OO is recessive, A & B are dominant
Incomplete Dominance is when a heterozygous gene (one dominant and one recessive) shows a “mix” of the twoPink flowers from a red and white allele
MENDEL What did he do?
Studied traits and inheritance in pea plantsCrossed purebred pea plantsOffspring, of F1 generationDominant and recessive alleles
ExampleRound seed is dominant and wrinkled is
recessiveYellow seed is dominant and green is
recessiveTall is dominant and short is recessive
PUNNETT SQUARES Method used to determine the
probability of offspring having recessive or dominant traits.
PRACTICE In humans, brown eyes (B) are dominant
over blue (b)
Blue eyed mom and homozygous brown eyed dad
Blue eyed mom and heterozygous dad
Heterozygous mom and dad
PRACTICE In dogs, there is an hereditary deafness
caused by a recessive gene, “d.”
What percentage of dogs would be deaf if…
Homozygous dominant and heterozygote
Heterozygote and homozygous recessive
Homozygous dominant and homozygous reccessive
2 heterozygotes
CLASSWORK/HOMEWORK Bikini Bottom Genetics worksheet
QUIZ ON FRIDAY!!!!
SQUIRRELS OF THE GRAND CANYON: Originally, there was only one species of
squirrel living in the Grand Canyon. As the Grand Canyon deepened and widened, the group of squirrels on the north side of the canyon got separated from the group on the south side. The squirrels separated on the north side now have black fur, while the squirrels on the south side have red fur. The separation of the two groups caused them to evolve different traits. The two groups are becoming more and more genetically different, and in time will likely become two different species.
CORN AND COWS: People have been selectively breeding
plants and animals for a long time. Native Americans produced corn by selectively breeding a species of weed. The corn they produced had ears that were only three inches long. Modern science has increased the length of the ears to one foot long. Farmers cross cows that produce the most milk to produce new generations of cows that produce increasing amounts of milk.
FINCHES As Charles Darwin conducted research
on the Galapagos Islands, he noticed differences in finches from island to island. One of the biggest differences was the sizes and shapes of the bird beaks. Each bird had the type of beak it needed to survive. Finches that ate insects had sharp needlelike beaks. Those that ate seeds had strong, wide beaks. The shape of the beak is an example of an adaptation, or change over time, that helped the birds survive.
POLAR BEARS Polar bears live in the Arctic areas. They
DO NOT live in the southern hemisphere
Adult males are 8-10 feet tall and weigh 550-1700 pounds
Adult females are 6-8 feet tall and weigh 200-700 pounds
POLAR BEARS Have 2 layers of fur. Their fur is clear
and hollow. It is oily and repels water.
They have a layer of blubber (fat) to insulate them. It can be up to 4.5 inches thick
Compact ears and small tail prevent heat loss
Bumps on feet keep them from slipping on the ice
POLAR BEARS Slightly webbed paws to help them
swim
Powerful claws to catch seals
Nose can detect prey from miles away
They can dig out shelters and curl up in them to get out of the cold, wind
POLAR BEARS Eat walruses, seals, small whales,
reindeer, birds, bird eggs, seaweed, small mammals, plants, berries
They try to kill a seal about every 5-6 days
POLAR BEARS In the wild, they live 15-18 years
In zoos, they can live 30-40 years
POLAR BEARS They do not hibernate
Mothers make dens when they give birth and the babies stay in it for about 4 months
Mothers usually have 2 cubs at a time
Baby polar bears are the size of a rat when they are born
POLAR BEARS Their predators are humans, other polar
bears, sometimes walruses.
Climate change is the biggest threat to bears
POLAR BEARS There are 25,000-40,000 polar bears in
the world.
In winter, polar bears sleep in shallow pits they dig in the snow with their sides or backs to the wind.
Polar bears need to have ice to hunt seals.