Evolution & Natural Selection Write Green! Chapter 13 Lesson 2

Observed tortoises, mockingbirds and finches. 1. Who is Charles Darwin A naturalist that explored the Galapagos Islands, in which he proposed the Theory of Natural Selection. Observed tortoises, mockingbirds and finches.

Wait….that’s confusing?? What is Natural Selection? the process by which organisms with variations that help them survive in their environment, live longer, compete better and reproduce more than those that do not have these variations. Wait….that’s confusing??

2. How does genetic variation & environmental factors contribute to evolution by natural selection and diversity? Variation is a slight difference in an inherited trait of individual members of a species.

3. How does variation happen? An adaptation variation (change) that makes an organism better suited to it’s environment. Structural Physical characteristics. Color, beak shape, etc. Camouflage and mimicry. Behavioral Hunting at night, moving in herds and conserving energy. Functional Internal body systems affecting biochemistry.

How many adaptations does this arctic fox have?

Natures Best Camouflages! https://youtu.be/EJGtN-igCu8?list=PLoHQGyBT6rWb5d6sYdJI0_yYnABJrV5jq

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

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

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

6. 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, not the genotype! 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 Pocket Mouse https://www.youtube.com/watch?v=sjeSEngKGrg

7. Evidence for Evolution Fossil record Homologous body structures Vestigial organs Embryology Biochemical evidence

a. Fossil record Use of fossils to record the history of life on Earth.

Archaeopteryx Missing link between reptiles and birds

B. Homologous body structures Similar anatomy in different types of animals because of common ancestor.

C. Vestigial organs “Leftover” traces of evolution that serve no purpose.

d. Embryology Embryos of all vertebrates are very similar early on

E. Biochemical DNA with more similar sequences suggest species are more closely related Humans and chimpanzees share more than 98% of identical DNA sequences.