Monday, December 19 Do Now Read pages 418-420 in the Biology Textbook on the tables. Define: Artificial Selection and Natural Selection Assign Yourself Natural Selection Practice Questions Take Out Materials Biorganizer – Cornell Notes page 80 Title: NATURAL SELECTION

Objective B.7C, B.7d, & B.7e The student is expected to analyze and evaluate how natural selection produces change in populations, not individuals. The student is expected to analyze and evaluate how the elements of natural selection, including inherited variation, the potential of a population to produce more offspring than can survive, and a finite supply of environmental resources, result in differential reproductive success. Analyze and evaluate the relationship of natural selection to adaptation and to the development of diversity in and among species.

Key Point #1: theory of evolution Evolution: The process of change over time Specifically, a change in the frequency of a gene or allele in a population over time

Key point #1 Charles darwin Father of Evolution Proposed a mechanism for evolution, called natural selection Darwin went on a 5-year trip around the world on the ship, the HMS Beagle As the ship’s naturalist, he made observations of organisms in South America and the Galapagos Islands Wrote a book, “Origin of the Species”

Key Point #1 cfu THINK-PAIR-SHARE What is evolution? Why is Charles Darwin called the father of evolution? What did Darwin study that brought him to his conclusion?

Key Point #2 natural selection Natural Selection: Organisms that are best adapted to an environment survive and reproduce more than others Darwin’s Theory of Natural Selection occurs in four steps: Overproduction Variation Competition Selection

1. Overproduction Each species produces more offspring that can survive

2. Variation Each individual has a unique combination of inherited traits. Adaptation: an inherited trait that increases an organism’s chances of survival

What adaptations do you see?

What adaptations do you see?

Why is Variation Important? Because the environment changes. The more variation within a species, the more likely it will survive EX: If everyone is the same, they are all vulnerable to the same environmental changes or diseases The more variation of types of species in an habitat, the more likely at least some will survive EX: Dinosaurs replaced by mammals

Which community has a better chance of surviving a natural disaster? Community A Community B

3. Competition Fitness: the ability to survive and reproduce Individuals COMPETE for limited resources: Food, water, space, mates Natural selection occurs through “Survival of the fittest” Fitness: the ability to survive and reproduce Not all individuals survive to adulthood

4. Selection The individuals with the best traits / adaptations will survive and have the opportunity to pass on it’s traits to offspring. Natural selection acts on the phenotype (physical appearance), not the genotype (genetic makeup) Ex: When a predator finds its prey, it is due to the prey’s physical characteristics, like color or slow speed, not the alleles (BB, Bb)

Individuals with traits that are not well suited to their environment either die or leave few offspring. Evolution occurs when good traits build up in a population over many generations and bad traits are eliminated by the death of the individuals.

Peppered Moth A Which moth will the bird catch? B

KEY POINT #2 CFU Overproduction Variation Competition Selection STOP AND JOT In your own words describe Darwin’s four steps of natural selection. Overproduction Variation Competition Selection

Analysis of Population Composition Guided Practice Independent Practice 5 Minutes Work with your partner to answer to questions on the next slides. 6 Minutes (Homework) Work on your own to complete homework.

Example: Moths on trees Peppered moths can be light or dark. This is an example of variation (different traits).

Example: Moths on trees When trees had white bark, the ___________ moths survived better, because it was harder for predators like birds to see them. Light moth Dark moth

Example: Moths on trees When trees had white bark, the light moths survived better, because it was harder for predators like birds to see them. Tree trunk Light moth Dark moth

Example: Moths on trees Since light moths survived better, they had more offspring. Since they had more offspring, most of the population was light colored. Population Most moths are light. Light moth Dark moth

Example: Moths on trees Due to pollution, the tree bark became dark. When this happened, the _____________ moths survived better. Tree trunk Light moth Dark moth

Example: Moths on trees Due to pollution, the tree bark became dark. When this happened, the dark moths survived better. Tree trunk Light moth Dark moth

Example: Moths on trees Since dark moths survived better, they had more offspring. Since they had more offspring, over time, most of the population became dark colored. Population Most moths are dark. Dark moth Light moth

Exit Ticket (7 min) Students will have 7 minutes to silently complete the exit ticket, and SHOULD use their notes from class.