7.1 Darwin’s Voyage

A.Darwin 1. Charles Darwin was a British ______________________. naturalist

2. He traveled for 5 years around the world on the ______________.HMS Beagle

3. He noted that plants and animals were very different from ones in England. He asked why…. a. This question led him to develop the theory of ____________________ by natural selection. evolution

B. Darwin’s Observations 1. During the voyage the Beagle stopped at the ______________ Islands which are off the coast of __________ ______________. Galapagos SouthAmerica

2. While on the islands Darwin observed incredible animal _________.diversity Lizards eating cactus Insects mimicking plants Giant Tortoises Harriet Darwin The Darwin Kids

C. Similarities and Differences (Mainland vs. Islands) 1. He noted similarities. The mainland and islands both had similar plants and animals. Example: ________________ and __________________ iguanasfinches

2. He also noted differences. Example: Iguanas -The mainland iguanas were ___________ and had _________claws to climb trees and grasp leaves from the trees. -The island iguanas were _____________ and had _________ claws to hold onto slippery rocks and grasp seaweed. greenshort dark graylong It appeared that once the mainland iguanas reached and inhabited the islands they reproduced, and eventually, over a ________ period of time, became different from their mainland relatives. long

Example – Finches: - Finches beak types were different from one island to the next. Island A had lots of insects but not many seeds. Their beaks were ____________ and _____________. Island B had lots of seeds but not many insects. Their beaks were ____________ and _____________. narrowpointed thickblunt

D. Evolution (From the Latin evolvere which means to unroll) 1. _____________ ____________ is a well tested concept or idea that explains a wide range of observations. 2. How did this theory develop? a. Darwin observed organisms on the Galapagos Islands that had slightly different traits when compared to the same mainland organisms. These slightly different traits which enabled them to survive on the island are called __________________. Adaptation – A _______ that helps an organism _________ and _____________ more successfully in its environment.. b. He reasoned that the organisms on the island faced different surroundings or _____________, compared to the mainland organisms. Scientifictheory adaptations environments trait survive reproduce

c. He also reasoned that species gradually changed over many ______________ and became ____________________ to the new island _________________. Environment - All ________ and _____________factors that affect an organisms ability to ___________ and ________________. (i.e. The place where you live ) generationsbetter adapted environment living non-living survivereproduce

E. Natural Selection Darwin wrote a book called The Origin of _____________ that proposed that evolution takes place by means of ___________ ___________. Species naturalselection

Natural Selection is the process by which individuals that are better _____________ to their environment are more likely to __________ and _____________, passing on their genes to the next generation. adapted survivereproduce

1.There are __________ factors that affect natural selection. a. ___________________- the production of more offspring than can possibly survive. Baby Spiders Overproduction THREE

b. ______________- members of a species differ from each other.Variation Pepper Moths

c. ________________- resources are limited and the offspring must struggle with each other for these limited resources. Some live, some die. Competition

F. Environmental factors 1. As overproduction, variation, and competition persist in a population of living things, ______________ ___________ ultimately determine which individuals will survive long enough to reproduce, and pass on their __________ (DNA). 2. Over time, genes for __________ (helpful) traits are passed on more than ___________ ones, gradually leading to adaptations that are well suited to that environment. Examples from the Galapagos: OrganismEnvironmentAdaptation IguanaBlack-lava, - slippery coastline- CormorantFood-poor shore,- food-rich ocean- Darker skin Longer Claws Shortened wings Stream-lined body environmental factors genes favorable unfavorable

Ex) Ground Finches of Daphne Major- In _____ years, more small seeds exist. Individuals with _________ beaks survive and reproduce more. ***Over time, the average beak size of this population will _____________. If conditions change, and _____ weather comes to the island, more large seeds will exist. Individuals with ________ beaks survive and reproduce more. ***The average beak size of this population will ___________. wetsmaller decrease dry larger increase 3. __________ in the Environment drive evolutionary changeChanges

4) __________ or __________ environmental changes require rapid adaptations or a species can become ________! Sudden drastic extinct Ex) Marine Iguanas of Santiago After the El Nino weather pattern dried up their food source, ________ iguanas on most islands were wiped out. Smaller populations on Santiago, which had __________ to a diet of thinner algae, survived, resulting in the ________ __________ that exist today. larger adapted smaller species