Purpose: In this investigation, we will find out how changes can occur in a population due to variation in traits

Inheritance

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






Nucleus

DNA and chromosomes are found inside the nucleus.

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






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


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






Human/Larkey Features Chart


Larkey Traits






Genes and Alleles






Documents

Purpose: In this investigation, we will find out how changes can occur in a population due to variation in traits