Chapter 6 Exam Evolution

• Evolution – theory that species change over time.
• Is it a theory or a fact?
• What is a species – groups of organisms whose members successfully reproduce among themselves
• How do species change?
• What causes Evolution to occur
• Main Theories explaining Evolution
• Lamarckism – Theory of Acquired Traits
• Species evolved by keeping traits their parents developed during their lives
• If a parent did not use a trait they did not pass that trait off to offspring
• Is salamanders did not use their legs they produced off springs without legs
• If you crop your dog’s ears he will produce puppies with cropped ears
• Theory of Use and Disuse
• As our needs changed, in order for us to meet those needs, we have to change in our lifetime, develop new traits to meet new needs
• New traits would dominate, old traits would fade away.
• Organisms developed new traits in their lifetime to meet changes in environment
• Snakes lost their legs because they didn’t use them
• Water birds – used wings less so they got smaller but webbed feet emerged
• Theories were all popular in 1700’s.
• What’s missing in these theories?Charles Darwin – Theory of Natural Selection
• Darwin was born in England in mid 1700’s
• Both dad and brother were doctors
• Idea was for him to be a doctor too.
• He didn’t like it much. He liked being outdoors looking at bugs and plant life. He liked nature.
• While he was studying medicine two of his professors heard of a sailing expedition that was going to sail around the continent of South America and map out the new lands they found.
• The name of the boat was the Beagle and they were able to get Darwin a position as the ship’s naturalist. His job was to collect samples of plants and animals from each of the islands they stopped at.
• Since the islands have never bee visited before the plants and animals had never been seen before.
• The Beagle set sail in 1831. What was supposed to be a 2-3 trip ended up lasting 5 years
• Galapagos Islands – is an archipelago, collection of small islands in the ocean.
• Formed by volcanoes millions of years ago. Like Hawaii.
• 563 miles off the coast of Ecuador, South America
• Group of 22 islands, 18 larger islands and 4 smaller ones.
• Famous for their endemic species, only found on those islands.
• Darwin’s Theory of Natural Selection – organisms with the traits best suited to their environment are more likely to survive and pass those traits off to future generations
• Published his theory in 1859, On The Origin of the Species By Means of Natural Selection
• Survival of the Fittest – goal is to possess the traits that allow you to live long enough to reproduce and pass on your traits to the next generation
• Darwin’s Four Observations
• 1. Organisms produce more offspring than can survive – Competition
• 2. Differences are found among individuals in a species, we are different from each other – Variations
• 3. Some variations give members advantages over other members in the population – Adaptations
• 4. Future generations will show more members possessing the advantageous variations - SurvivalVariations – an inherited trait that makes an individual different than other members of the same species
• How tall we are, hair color, skin color
• Adaptation – a variation that gives an organism an advantage over other members of the same species
• Adaptations can e physical, part of the body, or behavioral, how we act
• Physical – color, camouflage, size and shape
• Mimicry – a completely harmless species comes to look like a very dangerous species
• To ensure survival adaptations must provide 4 advantages
• 1. Find food/water - hunt
• 2. Help provide shelter – build a safe place
• 3. Attract a mate – be pretty

4. Help to avoid predators – defense

• Factors that create adaptations
• 1. Mutation – genes
• 2. Migration – genes moving into or out of a population
• 3. Geographic isolation
• 4. Climate Changes 6.2 Evidence of Evolution
• Fossils – any remains of life from an earlier time
• Relative Dating – dating the age of a fossil by its position in rock,
• Deeper fossils are older
• Radioactive Dating – radioactive elements decay over time. Scientists can measure the amount of radioactive element that has decayed to determine the age of a fossil
• More precise than relative dating.
• Other evidence of evolution – show relationship with other species
• Homologous Structures – body structures in different species that have a similar structure but are used for different purposes
• Show a common ancestor
• Vestigial Structures – body parts reduced in size and are no longer useful. Show relationship with other species
• Embryology – compare embryo development
• DNA – the more alike a species’ DNA is to another species, the more they have in common
• Human and ape – 99%
• 6.3 Primate Evolution –
• Primate – apelike, monkeys, apes, humans
• Characteristics
• 1. Opposable Thumbs – grasping tools and weapons
• 2. Binocular Vision – depth perception
• 3. Flexible Shoulders - swinging

4. Rotating forelimbs - swinging