Presentation on theme: "Organisms have thousands of genes, organized into chromosomes, which determine what the animal looks like and what it can do. Be sure to make the point."— Presentation transcript:
1 Organisms have thousands of genes, organized into chromosomes, which determine what the animal looks like and what it can do.Be sure to make the point that both plants and animals have chromosome.
2 In RoboRiot each robot has one gene with two “alleles” In RoboRiot each robot has one gene with two “alleles”. Each robot contributes one “allele” to the recycler.Explain that since the robots have only two alleles, the number of variations is limited.
3 In humans each gene has two alleles In humans each gene has two alleles. Each parent contributes one allele for a trait.Whereas Robot have only two alleles, humans have many 46 chromosomes each having with many genes. You may want to ask students if they know about the Human Genome project and how each gene is being mapped.
4 Heredity: An offspring gets one allele related to a trait from each of its parents. The two alleles are responsible for that trait in the offspring.AllelesIf students have learned about meiosis, they will be familiar with this concept. If they have not, it is important the help them understand that each parent contributes ½ of the offspring’s chromosomes.determine trait
5 in a gene are the same for a trait, the gene is homozygous. When the two allelesin a gene are the same for a trait, the gene is homozygous.When the two alleles in a gene are different for a trait, the gene is heterozygous.
6 When an organism has two alleles that are the same for a trait, both determine the trait. When an organism has two different alleles for a trait, only one trait is expressed.
7 The allele that is not expressed as a trait is called recessive. The allele that determinesthe trait is called dominant.dominantTrait:brown eyesThe allele that is not expressed as a trait is called recessive.recessive
8 The appearance of an organism is called its phenotype. All the information in the genes, both dominant and recessive, defines an organism’s genotype.The appearance of an organism is called its phenotype.
9 brown is dominant and blue is recessive. For the trait of brown or blue eye-color in humans, there are three possibilities:GenotypePhenotypehomozygous brownhomozygous blueheterozygous brownbrown eyesblue eyesbrown eyesBecausebrown is dominant and blue is recessive.
11 The alleles in some genes are neither dominant nor recessive The alleles in some genes are neither dominant nor recessive. Both alleles are expressed when the genotype is heterozygous. This is called co-dominance.Blood TypeBlood TypeBlood TypeAAABBBAB
12 When alleles are co-dominant: The phenotype isthe result of both allelesThe genotype is always heterozygousAAAABBBBAB
13 A species is defined as organisms that resemble one another, can mate, and produce offspring that can reproduce.You may want to tell students that while a horse and a donkey can mate, their offspring, called a mule, is sterile.etc…