Unit 2 Study Guide Test Date: ____________________Natural Selection & Adaptations

Charles Darwin Interested in organisms on the

Galapagos Islands Convinced all finches and tortoise

species had a common ancestor and changed over time to adapt to their food source in their environment

Knew each member of a species had variations (a slight difference in an inherited trait) because of decent with modification

Darwin developed the Theory of Evolution by Natural Selection

*Natural Selection*: process by which populations of organisms with favorable variations help them survive longer and reproduce more than those populations that do not have favorable variations

Also known as “Survival of the Fittest”

A trait that increases an organism’s fitness, ability to survive and reproduce in their environment, is called an adaptation

Adaptations occur over time as a result of natural selection selecting for favorable (fit) traits/variations.

Evolution: the process by which organisms have developed and changed over time

There are 4 types of evidence to support evolutions:

1. Comparative Anatomy2. Embryology 3. Fossil Record4. DNA

Genetically Modified Organisms (GMOs)When a gene from one organism is purposely moved to improve or change another organism in a laboratory, the result is a genetically modified organism (GMO). It is also sometimes called "transgenic" for transfer of genes.

Genetically modified foods or GM foods, also known as genetically engineered foods or bioengineered foods, are foods produced from organisms that have had changes introduced into their DNA using the methods of genetic engineering.

Commercial sale of genetically modified foods began in 1994. 

Arguments in SUPPORT of GM Foods

Scientific consensus says that GMOs are as safe to eat as any other food.

We need to grow more food on the same land we have to sustain the world’s growing population.

GMO crops in poor nations could increase farming profits and lift farmers out of poverty.

GM foods can be resistant to drought and pests to ensure food production for people.

Genetic modification of food is a powerful tool that could be used to end hunger around the world.

GM crops overall lead to less pesticide and chemical use from farmers.

Arguments AGAINST GM Foods

The risk assessment process is inadequate or flawed.

The safety of GMO plants that contain their own insecticide is in question.

GMO herbicide resistant plants may be over-sprayed with chemicals that may be toxic in certain levels.

The purpose of GMOs is seemingly to have intellectual property (patent rights) on seeds and plant breeding processes to make money for large companies.

All GM Food does not have to be labeled throughout the world, and consumers have a right to know if the food they buy is GMO-free.

GM Food is impacting the livelihood of small farmers.

GM food like factory fish may endanger native species.

Review InformationHomologous structures: similar structures in organisms each with different function

Analogous structures: same function but different structures

Vestigial structures: structure in an organism that has lost its function over time

Embryology: study of the development of an organism from one cell to birth

Using the diagram to the right, we can tell a human, monkey, and pig are closely related because they have very similar embryonic development. Human embryonic development is most similar to a monkey.

The salamander is the least complex organism. Its development and adult structure are very simple compared to the other organisms in the diagram.The fossil record contains information about every fossil discovered around the world. Studying these fossils from oldest to youngest give us information about how living things have changed over time.

The Principle of Superposition- Younger rock layers are on

top of older rock layers Fossils found in the same

layer are the same age (relative dating)

The younger fossils are more complex than the older fossils.