2 - Evolution Guided Notes

Unit 4: Evolution NOTES (Chapter 10) Evolution, or change over time, is the process by ____________________________________ _____________________________________________________________________________    

Charles ______________ – born in England Joined the crew of the H.M.S. _______________ Sailed around the world Made numerous _____________________ and collected evidence that led him to propose his hypothesis.

Darwin’s Observations Patterns of Diversity: Puzzled by where different species ____________________________________________ • Asked: Why were there no rabbits in Australia, despite the presence of habitats that seemed perfect for them? Why were there no kangaroos in England? Living Organisms and Fossils • Darwin collected and preserved __________________ • Fossils resembled organisms that _____________________________ – other looked completely unlike any creature he had ever seen. He Asked: ____________________________________________________________________? The Galapagos Islands • Most influenced Darwin • Although islands were so close together, the islands had very different ________________. • Fascinated by the land ______________ and marine ____________________ • Saw that giant tortoises varied in__________________ ways from one island to another. • The shape of a tortoise’s _____________ could be used to identify which island a particular tortoise lived. An Ancient, Changing Earth James _____________ and Charles _____________  Recognized that Earth is many _____________ of years old.  And the processes that changed Earth in the past are the same processes that operate in the _________________.

 Volcanoes release hot lava and gases now, just as they did on an ______________________  _____________ continues to carve out canyons, just as it did in the past.  Also said that awesome geological features could be built up or torn down over long periods of time. (examples: _____________________________________________) Darwin then asked: If the Earth could change over time, might ____________ change as well?

Lamarck’s Theory of Evolution Proposed that by selective _____________________ of organs, organisms acquired or lost certain traits during their lifetime. These traits could then be passed on to their _____________ Over time, this process led to ______________ in a species. Fiddler Crabs: An Example of Lamarck’s theory 1. The male crab uses its small front claw to attract mates and _______________ predators 2. Because the front claw has been used repeatedly, it ______________________. 3. A larger claw, is then passed on to the crab’s ____________________. He was WRONG! He did not realize that the large claw traits were inherited. According to Lamarck's theory, a given giraffe could, over a lifetime of straining to reach high branches, develop an elongated neck. The long neck is _____________________. Population Growth  Malthus (an economist) – observed that babies were being born ____________ than people were ______________. Carrying Capacity: The largest number of _______________________ of a population that a given environment can support.

The Origin of Species by Charles Darwin  The actual title is: The Origin of Species by Means of Natural Selection • The book proposed a mechanism for evolution that he called _________________________ • Presented evidence that demonstrating the process of _____________________ has been taking place for millions of year.

Darwin’s Arguments Natural Variation and Artificial Selection • Argued that species were ________________________ and unchanging. Natural Variation: There are ____________________ among individuals of a species. Ex: Some cows gave more milk than others & some plants _______ larger fruit than others. Artificial Selection: Nature provided the variation among different organisms, and humans selected those variations that they found _____________. * Only the largest hogs, fastest horses, and the cows that gave the most milk were ___________________________________________________________________________. Evolution by Natural Selection The Struggle for Existence: Means those members of each species _______________ regularly to obtain food, living space, and other necessities of life.  A predator that is the _____________ or has a particular way of catching prey can catch more prey.  ___________ that are faster, better camouflaged, or better protected avoid being caught. Survival of the Fittest: Process by which individuals that are ______________________ to their environment survive and reproduce most successfully; also called Natural Selection. *Darwin called the ability of an individual to survive and reproduce in its specific environment ___________________. *An adaptation is any __________________________________________ that increases an organism’s chance of survival.  The concept of fitness, Darwin argued, was _____________ to the process of evolution by natural selection. Example: Baby birds ______________________________________________________________________________ ______________________________________________________________________________

Descent with Modification: Principle that each living species has descended, with _______________, from other species over time. • Implies that all living organisms are _________________ to one another. Common Descent: The principle that says all species – living and extinct – were derived from common ________________________. Evidence of Evolution ______________ that had formed in the different layers of rock were evidence of gradual change over time. One could view how a species had changed and produced different species over time. Geographic Distribution of Living Species  Species now living on different ___________________ had each descended from different ancestors. However, because some animals on each continent were living under similar ________________ conditions, they were exposed to similar pressures of natural selection.  They ended up evolving certain striking features in __________________. This is called ____________________ Evolution Homologous Structures: Structures that have different _____________ forms in different organisms but develop from the _____________embryonic tissues. In their early stages of development, chickens, turtles, and rats look similar, providing _________________ that they shared a common ancestry. Analogous structures can be ________________________ similar in construction, but are NOT inherited from a common ancestor. Example: The wing of an __________ & the wing of an ____________ have the same function (both enable the organism to fly) – but are constructed in different ways & from different materials. * While analogous structures do not indicate close evolutionary relationships, they do show that functionally similar features can ___________________________ in similar environments. Vestigial Structures are structures that are the ______________ forms of functional structures in different species. Examples: 1. ____________________: The pelvis is the attachment point for legs and is therefore nonfunctional in an animal without legs 2. _______________: The wings of kiwis are too small to be of any use in flight 3. _________________________: Important for digestion in many mammals, but of limited use in humans & some apes  Mimicry: Adaptation in which one species evolves to ______________another species for protection or other advantages.  Camouflage: Adaptation that allows organisms to _____________ into their surrounds.