7.1 Darwin’s Voyage
Dec 30, 2015
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
South America
2. While on the islands Darwin observed incredible animal _________.diversity
Lizards eating cactus
Insects mimicking plants
Giant Tortoises
Harriet DarwinThe 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 __________________iguanas finches
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.
green short
dark gray long
It appeared that once the mainland iguanas reached and inhabitedthe 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 _____________.
narrow pointed
thick blunt
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.
Scientific theory
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 )
generations better adapted
environment
living non-living
survive reproduce
E. Natural Selection
Darwin wrote a book called The Origin of _____________ that
proposed that evolution takes place by means of
___________ ___________.
Species
natural selection
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.
adaptedsurvive reproduce
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:
Organism Environment Adaptation
Iguana Black-lava, - slippery coastline -
Cormorant Food-poor shore, - food-rich ocean -
Darker skinLonger Claws
Shortened wingsStream-lined body
environmental factors
genes
favorableunfavorable
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 ___________.
wet smaller
decrease
drylarger
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