Life Science Week 3 Notes

Life Science Week 3 Notes

Genetics and Heredity

1. Genetics

• Genes are groups of chromosomes in our DNA

• Comes from cells

• cells have 46 chromosomes

• 23 from mom, 23 from dad

• we study how animals change DNA over time (variation)

A gene is a segment of DNA. It will determine what you look like and what types of diseases you can have.

Species can change over millions of years. Lion ancestors were different then vs. now. How have these changes in genes happened?

Ancient horses: tiny, smaller brains, four toes

Horses today: large, fast, developed hooves

Multiple Choice

How many chromosomes does each cell have?

• 23

• 32

• 64

• 46

Multiple Choice

True or false:

Genes from a species can change over time

• True

• False

Multiple Choice

True or false:

Horses used to have 4 toes!

• True

• False

2. Survival of the fittest

• Species inherit traits that help them survive

• Better genes survive and are dominant

• Bad genes die. Less chance to reproduce offspring

• Example: Moth in England on darkened birch trees

Multiple Choice

How do genes get dominant?

• stronger genes do not survive as well as weaker genes

• weaker genes don't show up in babies

• stronger genes survive and get passed onto offspring

3. Pedigree

• a chart that shows ancestors and traits

• can have many generations (levels)

• some traits are not inherited but are learned

• some traits can happen because of environment

Flamingos are not born pink. The pink feather trait comes from their environment (shrimp and algae) not their parents.

Multiple Select

What does a pedigree chart show? *pick 2 answers*

• location of families

• ancestors

• traits

• learned behavior

• chromosomes

Multiple Choice

What is a level of a pedigree called?

• a dominant trait

• a generation

• a learned trait

• environment

Multiple Choice

Flamingos are pink because of...

• the pink feathers from their parents

• the DNA for pink feathers

• environmental conditions

• it helps them camouflage

4. Clones vs. Hybrids

• Clones are exact gene duplicates

• Hybrids is a mix of genes from two species

• Hybrids can result in good genes from both parents

• Hybrid plants from cross-pollination

Hybrid animals

Hybrid plants: Can you guess what these hybrid plants were mixed with? Hybrids are made for fun, better nutritional value, resistance to bugs, or taste.

Multiple Choice

True or False:

Clones are mixed from 2 species

• True

• False

Multiple Choice

True or False:

Only animals can be made into hybrids

• True

• False

ANSWERS:

• Kalettes = kale + brussel sprouts

• Pluot = plums + apricots

• Ugli fruit = grapefruit + orange + tangerine