Purpose: In this investigation, we will find out how changes can occur in a population due to...
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Transcript of Purpose: In this investigation, we will find out how changes can occur in a population due to...
Purpose
Purpose: In this investigation, we will find out how changes can occur in a population due to variation in traits.
Background Information Traits in a population change over the
course of several generations Offspring grow up to look pretty much like
their parents. This is because the information for how to
develop is passed from the parents to the offspring
Passing genetic information from one generation to the next generation is called inheritance.
You inherit alleles from your parents, Larkeys inherit alleles from their parents. This is true for all living organisms.
Gregor Mendel
The pioneering work on inheritance was done by an Augustinian monk named Gregor Mendel.
He spent years growing thousands of plants and animals, observing closely to see how similar they were to their parents.
His most important work was done with pea plants.
Mendel reasoned that the offspring must be inheriting something from each parent.
Cells
Everything is made of cells. This is where the information
describing how to make you resides (is found)
Cells have many smaller structures inside, called organelles, which perform functions essential to life.
Animal Cell
http://www.fossweb.com/modulesMS/kit_multimedia/PopulationsandEcosystems/pdfs/transparencies/Pop_Eco_transp_22.pdf
DNA
Found inside the nucleus of a cell Also known as the inheritance
messenger DNA contains millions of atoms In order to fit inside the nucleus, DNA
is coiled and coiled again into structures called chromosomes.
Chromosomes
Chromosomes are the structures that carry the message of inheritance.
They come in almost identical pairs They have specific active locations
called alleles
Chromosomes and Genes
http://www.fossweb.com/modulesMS/kit_multimedia/PopulationsandEcosystems/pdfs/transparencies/Pop_Eco_transp_23.pdf
Chromosomes
The drawing shows the nucleus of a cell from our make-believe animal, the Larkey.
There are 8 chromosomes Chromosomes always come in pairs. The Larkey has 4 pairs of chromosomes. Both chromosomes in a pair have dark areas
in exactly the same location. The dark areas are called alleles.
Two pairs of alleles working together make a gene
Alleles
The alleles are the code that determines the traits
The combination of alleles in an organism’s chromosomes is the organism’s genotype.
Two Alleles on paired chromosomes work together.
Together they are known as a gene Alleles don’t all have equal influence in
determining traits
Dominant/Recessive Alleles
Dominant alleles are more influential in determining traits
They are represented by an uppercase letter
Recessive alleles are less influential in determining traits
They are represented by a lowercase letter
Larkey Genetics Code AA or Aa = __________ legs aa = __________ legs
EE or Ee = __________ eyes ee = __________ eyes
FF = striped fur pattern Ff = solid fur pattern ff = spotted fur pattern
TT or Tt = __________ tail tt = __________ tail
From Genotype to Phenotype
http://www.fossweb.com/modulesMS/kit_multimedia/PopulationsandEcosystems/pdfs/transparencies/Pop_Eco_transp_26.pdf
Genes
A gene is two alleles working together to control a trait
They determine eye color, hair color, fur patterns, etc.
Larkey Features
A Larkey has four features that we will focus on:
Legs (appendages) Eye color Fur pattern Tail shape
Each feature is controlled by one gene. Each of the four genes are located on
a different chromosome
Gene Locations
http://www.fossweb.com/modulesMS/kit_multimedia/PopulationsandEcosystems/pdfs/transparencies/Pop_Eco_transp_25.pdf
Human/Larkey Features Chart
http://www.fossweb.com/modulesMS/kit_multimedia/PopulationsandEcosystems/pdfs/transparencies/Pop_Eco_transp_20.pdf
Larkey Traits
http://www.fossweb.com/modulesMS/kit_multimedia/PopulationsandEcosystems/pdfs/transparencies/Pop_Eco_transp_21.pdf
Genes and Alleles
http://www.fossweb.com/modulesMS/kit_multimedia/PopulationsandEcosystems/pdfs/transparencies/Pop_Eco_transp_24.pdf