Peppered Moth Evolution

• Melanism

Answer on a separate sheet1. What are the two types of peppered moths?2. What color were most peppered moths originally?3. What changed in the environment of the peppered moth?

What caused this change?4. After the change in environment, which color was a positive

adaptation?5. What is melanism?6. Why did the birds eat the light colored moths more than

the dark colored moths?7. How does the peppered moth support the theory of

evolution?

Peppered Moth Activity

• Pick a spot in the room to camouflage your moth• Color the moth to blend in to the room– 6 points for one color– 7 points for 2 colors– 8 points for 3 colors

• Put the moth in the correct spot to camouflage it.• You will receive 2 points if it is not found and 0 points

if it is found

Evolution

What is evolution?

• The process by which modern organisms have descended from ancient organisms

• Changes that are beneficial (adaptations) are passed on to offspring

• Goal of all living things: pass genes on to another generation– Good adaptations increase fitness– Bad adaptations – what happens?

Charles Darwin

• Theory of evolution by natural selection

• Voyage on the Beagle– Galapagos Islands

• On the origin of species…

Voyage of the Beagle

• Charles Darwin– Born in England,

1809– Boarded the Beagle

in 1831 for it’s journey around the world

The Voyage of the Beagle

Darwin’s Observations – Evolution by Natural Selection

• Patterns of Diversity– Darwin noticed that organisms living in different

habitats and environments had very different traits

– And…similar environments had organisms with similar traits

• Struggle for existence – species compete for resources

Darwin’s Observations – Evolution by Natural Selection

• Descent with modification – new species descend (come from) other species with changes (modifications)

• Survival of the fittest – the fittest organisms will live and pass their genes on to a new generation

Evolution by Natural Selection

• Darwin used his observations to come up with the theory of evolution by natural selection

• The environment will determine which organisms will live or die– Pass their genes on to a new generation– Determined by adaptations – traits of an organism

Adaptations

• Darwin looked at the finches on the Galapagos Islands– Noticed beak shape differed– Why would the beak shape be different?

• Darwin looked at the finches on the Galapagos Islands– Noticed beak shape differed– Why would the beak shape be different?

– Diet– Habitat– Defense mechanism

Adaptations

Evolution

• Fitness: ability of an organism to survive and reproduce viable offspring– Viable offspring are offspring that can survive and

reproduce

• Adaptation: characteristic in an organism that increases fitness

Natural Selection vs. Artificial Selection

• Natural Selection: environment chooses which traits are beneficial and will increase fitness

• Artificial selection: humans choose which traits are beneficial– Examples: breeding dogs

Battle of the Beaks Class TotalsBeak Paper Clips Macaroni Rubber Bands Toothpicks

Scissors

Plastic Spoons

Clothes Pins

Binder Clips

Evidence for Evolution

Evidence for Evolution

• Fossils• Geographic distribution• Homologous body structures• Vestigial organs• Similarities in embryology

Fossils

• Fossils: remains of ancient life• Shows progression from ancient to modern

Fossil Record: Determining Age

• Radioactive Dating: use element’s half-life to determine age of fossil– Half life: how long it takes for half of the element

to decay or disappear from the fossil• Relative Dating: look at which layer of rock the

fossil was found in to compare age to other fossils around it

Geographic Distribution

• Animals living in similar environments have similar anatomies and behaviors– Showed that evolution in similar environments

caused certain traits to be chosen as beneficial• Each animal experienced descent with

modification from common ancestors

Homologous Body Structures

• Structures that have different mature forms but develop from the same embryonic tissue

• Limbs of reptiles, birds, mammals (arms, wings, legs, flippers) all come from the same basic bones

Homologous Limbs

Homologous Limbs

Vestigial organs

• Traces of homologous organs in other species• Organs are not necessary for survival• May resemble miniature legs, tails or other

structures• Examples in humans: – Tail bone– Appendix

Similarities in Embryology

• Embryology: study of embryos, development before birth, hatching

• Development in vertebrates is extremely similar

• Common tissues and developmental patterns

Calf, chick, fish, hog, human, rabbit, salamander, tortoise

Calf, chick, fish, hog, human, rabbit, salamander, tortoise

Calf, chick, fish, hog, human, rabbit, salamander, tortoise

Human Evolution

Human Evolution

• Hominids – “great apes”– Human ancestors AND humans belong to this

group• Similarities in body structures, DNA, development

• Over time, organisms changed

Human Evolution

Human Evolution

• As human ancestors moved from location to location, traits were deemed beneficial or not

• Different traits, different environments caused changes in humans and our ancestors over time

Human Cladogram