120 likes | 252 Views
GENETICS. Lavender . TRUE or FALSE?. Like mixing paints, parents’ traits always blend in their offspring. If you look more like your mother than your father, then you received more traits from your mother. New DNA is copied from existing DNA. What makes you unique?. Earlobes? Thumbs?
E N D
GENETICS Lavender
TRUE or FALSE? • Like mixing paints, parents’ traits always blend in their offspring. • If you look more like your mother than your father, then you received more traits from your mother. • New DNA is copied from existing DNA.
What makes you unique? • Earlobes? • Thumbs? • Interlacing fingers? Why might some students have types of traits that others do not?
Genetics • The study of how traits are passed from parents to offspring. • Gregor Mendel – the father of genetics • An Austrian monk • Performed experiments that helped answer questions about heredity and disprove the idea of blending inheritance • Mendel
Heredity & Traits • Heredity: The passing of traits from parents to offspring. • Traits: a distinguishing characteristic or quality, especially of one's personal nature
Mendel’s Experiments • Mendel used PEA PLANTS to study genetics • They reproduce quickly = lots of data • They have easily observed traits (flower color, pea shape) • He could control reproduction – which plants result in which traits
Pollination in Pea Plants • Read this section on page 672. • Jot down notes • Draw the diagram from figure 1. • Answer the following questions. • Would this pea plant be more likely to self-pollinate or to cross-pollinate? • What does the arrow indicate is happening to the pollen?
True Breed vs. Cross Pollination • Mendel began his experiments with true breed pea plants. • Ex: When a round pea plant self-pollinates it always produces round pea plants. • Mendel used true breed pea plants to cross pollinate. • Observe figure 2 – he crossed a purple flower with a white flower to observe the TRAITS that appeared in the offspring. • He did this with flower color, seed color, seed shape
Mendel’s Results • First generation crosses • Purple x Purple = Purple • White x White = White • Purple x White = Purple • WHY? This led to Mendel conducting second-generation crosses…
Second Generation Crosses • Hybrid plants – purple plants (came from purple x white) • He crossed two purple hybrid plants • Observe figure 4 (pg 675) • The trait that disappeared in the first generation (white) always reappeared in the second generation.
Observe Mendel’s Data • Page 676 – Table 1 • What characteristics did Gregor Mendel study? • What do you notice about the ratio?
Mendel’s Conclusion • When organisms reproduce, each reproductive cell (sperm & egg) contributes one factor for each trait. • Dominant – a genetic factor that blocks another genetic factor • Recessive – a genetic factor that is blocked by the presence of a dominant factor (only observed when 2 recessive factors are present)