Monday, April 25 th Big Idea: What role do chromosomes play in inheritance Daily target: I can describe how genetic diversity is done in sexual reproduction Homework: Bookwork DUE (TURN IT IN!) Vocabulary: Gamete- a mature sexual reproductive cell, as a sperm or egg, that unites with another cell to form a new organism. Homologous Chromosomes- two chromosomes, one of paternal origin, the other of maternal origin, that are identical in appearance and pair during meiosis. Entry Task: Which stages of Meiosis look exactly the same as the PMAT stages of Mitosis? Conclusion: Describe how you end up with half of each parent’s chromosomes. Plan for Today: Finish Meiosis notes

Sexual Reproduction Requires two parents that each share ½ of the genetic information. Offspring share the characteristics of each parent. Meiosis 2

Sexual Reproduction All the members of the Animal Kingdom Fish Mammals Amphibians Birds Reptiles Insects Crustaceans 3

Sexual Reproduction Plant Kingdom Flowers are the reproductive organs of plants. Some flowers have both male and female reproductive organs on the same flower. 4 Male flower Female flower

Sexual Reproduction Examples of organisms that reproduce sexually Chickens Iguanas Lobsters Sharks Humans Butterflies Sunflowers Roses 5

Sexual Reproduction Happens 2 ways Internally (inside) The egg is fertilized by sperm inside the female Mammals, birds, reptiles, insects, spiders Externally (outside) The egg is fertilized by sperm outside the female The female lays the eggs and then the male fertilizes them. Fish and some amphibians Plants and fungi (pollen and spores) 6

Sexual Reproduction Advantages 1. More Variation (more differences within a species) Due to there being two parents, each parent passes on their DNA. The new offspring becomes a combination of both parents. You have some characteristics of your mother AND your father.

2.Species can evolve over time (due to there being so much variation) Due to organisms being slightly different, characteristics or features can be better than others. Organisms that have these features may get more food, find more mates, survive in harsher conditions. The weaker organisms die out leaving the stronger better suited organisms. Think about it…will a male white tail deer that is stronger with larger antlers get more mates or one that is weaker with small antlers? Would a snake that blends in with the environment avoid getting eaten or would one that is white so predators can see it? Advantages Bats wings have evolved over time

Advantages 3. New characteristics or traits may form (due to there being so much variation) This is a picture of a female and a male Frigate bird. The male has a large red pouch that he uses to attract mates. Back in the day, none of the males had a red pouch. Through a random mutation, one of the males was born with a small red pouch. The female birds found him attractive! Since he mated with more female birds than the others, this trait was passed on. Now ALL the male frigate birds have this red pouch. The ones that don’t have it didn’t get any mates and died off.

Sexual Reproduction Advantages 4. Less chance that diseases will be passed on Due to there being two parents, each parent contributes DNA. If one of the parents has a disease or disorder, it is more unlikely to be passed on due to their DNA combining with another’s. Keep in mind, we are talking about ALL organisms that reproduce sexually: plants and animals! Many plants and animals have SEVERAL offspring at once.

Sexual Reproduction Disadvantages 1. Only half of the population can reproduce Since only half of the population can reproduce, the other half depend on them to create offspring.

2. It takes two organisms to create new offspring. A male and female must find each other. Within the wild this may be difficult. It requires energy to search for and find a mate. I’m lonely, so lonely...

3. Courtship and having a baby requires a lot of energy In many cases, the male spends a great deal of energy trying to get the female to like him. This can even put the male into dangerous situations. The mom, while pregnant, requires more food and often can’t run/escape from predators as easily. This male bird is performing a dance to attract a mate. This female Hyena can’t run as fast now (big belly!) Ready? Imma ‘bout to twerk!