Unit B Chapter1 History of Life on Earth

Geological Evolution The Earth’s surface is always changing and evolving. What is that word we use to describe that the Earth is always changing?

Technological Evolution Technology is always evolving and changing over time. How have cell phones changed in the last ten years, 5 years, or even 2 years? Technology is always evolving or changing, just like life.

Biological Evolution Life on the planet is always in a state of change Fossils Fossil evidence helps to support this How do you think fossil evidence helps to support that species change over time?

Video of Evolution of Whales

Evidence for change in life Mass extinctions: Huge numbers of organisms go extinct at around the same time period Many theories to why New species always develop afterwards Dinosaurs died out, leaving room for hairy mammals to adapt to the cold of the ice age

Mass Extinctions Cretaceous extinction 65 million years ago again 90% of life died out Scientists think meteor hit somewhere in Mexico, turn to pg. B15 in book.

Evidence to support change in life Evolution-theory that species change over time Traits passed from one generation to the next Slowly can change over time

Early Ideas Jean-Baptiste de Lamarck First to say species can adapt during their life and pass traits onto their offspring Giraffes neck was his evidence Each generation was reaching to higher leaves and thus pass that on to babies - He had no real evidence to support his ideas

Charles Darwin Took a 5 year voyage around the world to develop his theory of Natural Selection: members of a species best suited to an environment reproduce more at a higher rate than other members of a species. This leads to changes over time Most of his evidence taken from turtles and finches on islands

Natural Selection through adaptation example You and I are running from a bear. If you run faster than me, who is the bear going to catch? Who will be able to produce more fast runners? You were able to adapt faster then me. Your natural born speed enabled you to produce more offspring with your similar speed.

Darwin's Evidence He visited the Galapagos Islands and saw the same type of turtles and finches (type of birds) who developed on different islands. The turtles and finches adapted through natural selection. This supported his theory of evolution.

Different Islands had different climates Finches Adapted with the size of their beaks depending on their food source.

Each bird developed on a different island

Speciation on different islands

Turtles adapted by their body structure

These are turtles found on different islands

Artificial Selection When humans selectively breed animals and plants. This is true of some dog and plant species

Artificial evolution of peppers and dogs is an a example

Let’s Practice Figuring out natural selection of some finches and turtles

4 main driving forces of evolution by natural selection Overproduction Variation Adaptation Selection

Overproduction If an animal produces enough offspring some will survive Can you even think of things that ONLY have the ability to produce ONLY 1 offspring? NO Salmon Lay several thousand eggs, only a few hundred will survive the disease and predators in the streams Only a few dozen will make it long enough to breed

Overproduction of Pinecones

Variation Natural differences that help things to survive Predators-ability to catch their meals vs. Prey- ability to elude the predators Most of the time these are mutations Curved tail in a salmon allows it to swim faster

Different variations in colors of shellfish

Adaptation An inherited trait that gives an organism an advantage The curved tail allows the salmon to swim faster and a bear can’t catch it.

Same species of fish with different mouths to eat different things.

Selection Those animals born with a selective advantage survive longer Those salmon with tails that allow it to swim faster, live longer, will have more babies just like them.

Video of 4 driving forces.

Review: Ask your partner the questions. BUT SWITCH EACH TIME Review: Ask your partner the questions. BUT SWITCH EACH TIME. Record their responses What do you know about overproduction and how it helps evolution? What could you predict about adaptation of animals leads to evolution? What is the relationship between variation and selection? What is an example of adaptation?

Whole picture of biological evolution Overproduction + Variation + Adaptation+ Selection= Natural Selection driving Evolution.

Speciation Evolution of a new species from an existing one

What causes it? Usually physical isolation from each other and their ability to adapt to a new location Again think of the Galapagos Islands turtles and finches

Separated by mountains

Separated by a canyon

Evidence to support evolution Fossils Biological Structure Genetics

Fossil Evidence Supports Evolution Comparing fossils over time shows that there is a connection. The geologic time scale helps to show this

Elephant fossil timeline leads to one original ancestor

Dog fossils and structures lead back to one original species

Biological Structures Comparing today’s animals and plants to those in the fossil record help to provide evidence Vestigial Organs-are physical structures that were fully developed and functioning in an earlier group of organisms but are reduced and unused in later species.

Similar arm (wing) structure=similar ancestor

Vestigial organ: leg bones in whales

Vestigial Organ: Appendix in humans

Vestigial Organs: Wisdom teeth humans

Vestigial Organs: Wings of flightless birds

Evidence of hind legs on dolphins

Genetic Evidence Scientists can now examine the DNA of organisms and have also notices similarities in animals from the past and today. Same “stuff” in different animals=common ancestor

DNA comparisons

Write a paragraph at least 7 sentences long describing how fossils, biological evidence, and genetics support the theory of evolution. Be sure to talk about vestigial organs