Evolution Notes

Yes it is…. Evolution is ‘just’ a theory isn’t it? but what is a theory anyway? Popular Definition of a Theory - a “_____” or “hunch”. guess Scientific Definition of a Theory - a well-substantiated __________ of an aspect of the natural world. Scientific Theories are based on _______, facts, and have been ______ in many ways. explanation evidence tested

Where did the Theory of Evolution come from? The theory of evolution was thought of by both _______ ______ and ______ ______ _______. Charles Darwin Alfred Russell Wallace

Charles Darwin studied traits of organisms on the ________ Islands and developed the theory of evolution by ______ ________. Galapagos natural selection

survival of the fittest Alfred Russell Wallace studied traits of organisms on the _____ Archipelago of islands and coined the term “__________________”. Malay survival of the fittest

This is an Agrias butterfly from South America What is Evolution? Evolution is the process of species _______________ to better suit their environment. Species: a group of organisms that can ____ with one another to produce ______ offspring. changing over time This is an Agrias butterfly from South America mate fertile

Mutations: ______ to an organism’s DNA made during ______. Species change over time because of ________ and ______________. mutations natural selection Mutations: ______ to an organism’s DNA made during ______. Mutations create ________ in a population. changes Point of Mutation meiosis variations

Which color variation do you think is better suited to survive? Natural Selection In Natural Selection organisms with favorable _____ best suited to their environment are more likely to ______ and _________. traits survive reproduce Which color variation do you think is better suited to survive?

The Process of Natural Selection 1. Overproduction: organisms in a population produce more ________ than their environment can support. Not all offspring will ______ long enough to reproduce. offspring survive Green Sea Turtles lay 100 eggs in a “clutch” Only one or two will survive to adulthood

The Process of Natural Selection 2. There must be ________ within the species. Variation: _________ among _____ between individuals of the same species. variations differences traits

Variations must be _______ from an organism’s parents. inherited

The Process of Natural Selection 3. Organisms _______ to ______ in their environment. Starvation, ______, competition & ________ limit populations of all species. struggle survive disease predation

helpful traits survive environment reproduce Organisms that survive the struggle have ______ variations of _____ (adaptations) that help them ______. Adaptations: features that make an organism suited for its __________ so it can survive, _________, & pass its genes/ alleles onto its offspring. helpful traits survive environment reproduce The environment changes and it becomes too cold for dogs with short and medium fur.

What is the flies adaptation? Here’s an example of Evolution in action. This is happening all over the world! What is the flies adaptation?

The Process of Natural Selection 4. Selection (successful reproduction): The members of a population that have ________ helpful variations of traits will be more likely to ______ and ________. inherited survive reproduce A saddleback tortoise from Pinzón Island

How do new species form? speciation one evolves two species That’s called _________: the formation of a new species as a result of evolution. Speciation occurs when ___ species ______ into ___ different ______ that can’t reproduce with each other anymore. speciation one evolves two species

group separated caused movement plates How do new species form? 1. Separation - when a _____ of individuals becomes _________ from the rest of the population. Can be ______ by a newly formed canyon, mountain range, lake or ________ of Earth’s tectonic _____. group separated caused movement plates

groups affected selection Different traits favored spread How do new species form? 2. Adaptation - Separated ______ continue to be ________ by natural ________ in their new, different environments. ________ _____ can be _______ and over many generations can ______ through the population. groups affected selection Different traits favored spread Kaibab squirrel Abert squirrel The formation of the grand canyon separated the Tassel-Eared squirrel population. Over time the different environments favored different traits causing the formation of two new species.

successfully How do new species form? populations mate two different 3. Reproductive Isolation - Over time the separated _________ can become so different that they may ____ be able to _____ __________ with each other anymore. The populations are now considered to be ___ ________ ______. populations NOT mate successfully two different species

This example shows how the finches on the Galapagos Islands may have evolved.

Is there Evidence for Evolution? Lots….. fossil genetic biological

Fossil Evidence fossil record examining changed over time The _____ ______ is all of the fossils that have been found. By _________ the fossil record we can see what lived in the past. Comparing organisms in the fossil record provides evidence for how organisms have ________________. fossil record examining changed over time

Do we have any fossil evidence for intermediate species. Land Mammal ? Do we have any fossil evidence for intermediate species.

All of these are intermediate species

Embryology – The study of early development in ________. Biological Evidence Embryology – The study of early development in ________. organisms During early __________, the embryos of a shark, a rabbit, and a gorilla look similar. This suggests an evolutionary __________ among all vertebrates. development relationship

Homologous Structures Homologous Structures are similar structures with ________ functions. different The ____ ________ of the human arm, the front leg of a cat, the front flipper of a dolphin, and the wing of a bat are all ______. bone structure similar

Vestigial Organs/Structures Vestigial Organs show how some modern ________ are related to ancestors. organisms For Example: Whales have small ___ bones. hip

Genetic Evidence comparing DNA similar related Scientists can tell how closely organisms are related by ________ their ____. The more ______ the DNA, the more closely ______ the organisms are (possibly evolved from common ancestor). comparing DNA similar related

How do we show evolutionary relationships? Use ________ _______ to show how organisms are related. branching diagrams Branching diagrams (cladograms) show which _____________ organisms _____ and when these organisms ______. characteristics share evolved

These are the derived characteristics Organisms are _______ in the diagram by their ______ _______ _____________. grouped shared derived characteristics Derived characteristic: a ____ that two or more kinds of _________ _____ with their most recent common ________. trait organisms share ancestor These are the derived characteristics

more characteristics more related The ____ derived ____________ organisms share, the ____ closely ______ the organisms probably are. more characteristics more related The house cat is more closely related to the lion because they have the most characteristics in common (having hair, mammary glands, birthing live young & retractable claws).

shared organisms above Each characteristic listed on the diagram is only ______ by the ________ _____ it. shared organisms above The Brown bear has the characteristics of hair, mammary glands & birthing live young. It does not have retractable claws and the ability to purr. These characteristics are listed above the Brown bear in the diagram, therefore it does not have them.

Characteristics shown _____ on the _______ are more _____ than the characteristics below them. higher diagram recent The ability to purr is listed highest (or last) on the diagram. This means it is the most recent characteristic to evolve and only the house cat has it. most recent The characteristic of having hair & mammary glands is listed first on the diagram. This means it evolved first, or it is the oldest characteristic in the diagram. All organisms in the diagram have this characteristic. oldest