Presentation is loading. Please wait.

Presentation is loading. Please wait.

is the transmission of traits from one generation to the next.

Similar presentations

Presentation on theme: "is the transmission of traits from one generation to the next."— Presentation transcript:


2 is the transmission of traits from one generation to the next.

3 Who was Gregor Mendel? Gregor Mendel was born in 1822 in Heinzendorf, Austria. Mendel grew up on a farm and learned a lot about flowers and fruit trees. When he was 21 years old, he entered a monastery. The monks taught science and performed many scientific experiments. Mendel was sent to Vienna where he could receive training in teaching. However, Mendel had trouble taking tests. Although he did well in school, he was unable to pass the final exam. He returned to the monastery and put most of his energy into research. Mendel discovered the principles of heredity in the monastery garden by studying pea plants.

4 From his previous work with plants, Mendel knew
that the patterns of inheritance were not always clear. For example, sometimes a trait that appeared in one generation was not present in the next generation. In the third generation, though, the trait showed up again. Mendel noticed these kinds of patterns in several other living things too. Mendel wanted to learn more about what was causing these patterns. To keep his investigation simple, Mendel decided to study only one kind of organism. Because he had studied garden pea plants before, they seemed like a good choice. Like many good ideas, Gregor Mendel’s ideas were not understood at first. In 1865, Mendel wrote about his studies, but it wasn’t until after his death, more than 30 years later, that he finally got the recognition he deserved. Once Mendel’s ideas were found and understood, the door was open to modern genetics.

5 are characteristics or features of an organism that are inherited
(passed from parent to offspring). Examples nose shape eye color hair type and color

6 Some traits are passed on and others are not
Dominant traits are traits that hide other traits when passed on to offspring Recessive traits are the traits that get hidden by dominant traits blue eyes Recessive trait Brown Eyes Dominant trait Brown Eyes

7 Which traits do you have that are dominant? Which are recessive?
Let’s take a look at a few examples. Thumb Shape Earlobes Straight Dominant Hitchhiker’s Recessive Hanging free Dominant Attached Recessive

8 Why are some traits passed on and others are not
Why are some traits passed on and others are not? The answer lies in our Cells. Scientist began to experiment with plants and animals to learn how traits are passed on from parents to offspring.

9 Vocabulary Review The cell is a membrane covered structure
that has all the materials necessary for life. Nucleus - contains all the genetic information for all life processes. Chromosomes are long molecules of DNA; found in the nucleus of eukaryotic cells. DNA - “deoxyribonucleic acid”; heredity material that controls all the activities of a cell.

10 Not all organisms have a nucleus, but all organisms have genes.
Genes are contained in DNA. basic unit of heredity determines a persons traits (characteristics) passed on from parent to offspring through asexual or sexual reproduction

11 Cells nucleus - chromosomes DNA - genes - traits Chromosomes

12 Alleles are the different forms of a gene.
Alleles come in pairs, one set from your father the other set from your mother. Geneticists use letters to represent alleles. Example: Alleles come in pairs, and the allele for having a Widow's Peak is thought to be dominant, so you only need one copy present to have the trait. Widow’s peak Straight hairline

13 Genotype vs Phenotype Genotype is the combination of
alleles an organism inherits from its parents (genes). Phenotype is the organisms appearance (physical). WW, Ww Widow’s peak ww Straight hairline

14 Genotype vs Phenotype Other Examples:

15 Punnett Square The Punnett square is a diagram that is
used to predict the outcome of a particular cross or breeding experiment. It is named after Reginald C. Punnett, and is used by biologists to determine the probability of an offspring having a particular genotype. The Punnett square is a summary of every possible combination of one maternal allele with one paternal allele for each gene being studied in the cross.


Download ppt "is the transmission of traits from one generation to the next."

Similar presentations

Ads by Google