Lessons 6-1 and 6-2 Flashcards
Species
A group of similar organisms that can mate with each other and produce fertile offspring
Fossil
The preserved remains or traces of an organism that lived in the past
What was the Beagle?
The ship that Charles Darwin travled on
Where did Darwin explore?
The Galapagos Islands
What was Charles Darwin?
A naturalist
What did Charles Darwin compare?
Galapagos Islands organisms to organisms elsewhere
Adaptation
A trait that increases an organisms ability to survive and reproduce
Evolution
The process of change over time
What was Darwin’s Hypothesis?
Darwin hypothesized that species change over many generations and become better adapted to new conditions
What were Darwin’s ideas often reffered to as?
The theory of evolution
Scientific Theory
A well-tested concept that explains a wide range of observations
What did Darwin conclude about organisms on the Galapagos
That they had changed overtime
Artificial Selection
When only the organisms with a desired characteristic are bred
How are artificial and natural selection different?
Artificial Selection is done by human descicion and natural selection is done in nature, naturally
What are the three factors that affect the process of natural selection?
Overproduction, variation, and competition
What was the book that Darwin wrote?
The Origin of Species
Overproduction
In many species, so many offspring are produced that there are not enough recources - food, water, and living space - for all of them
Variation
Any difference between individuals of the same species
Competition
Since food, space, and other recources are limited, the members of a species must compete with one another to survive
Environmental Change
A change in the environment can affect an organisms ability to survive and therefore lead to natural selection
How are variations passed on?
Variations can result from changes in genes and the shuffling of different forms of genes when egg and sperm join
What evidence supports evolution?
Fossils, similar body structures, patterns in early development, and similarites in DNA and protein structures
How do fossils support evolution?
By examining fossils scientists can infer the structures of ancient organisms. Fossils show that, in many cases, organisms that lived in the past are very different from organisms alive today.
How do similarities in body structure support evolution?
Fishes, amphibians, reptiles, birds, and mammals all have an internal skeleton with a backbone. This similarity provides evidence that these animal groups all evolve from a common ancestor.
What is a homologous structure?
Similar structures that related species have inherited from a commen anscestor
How do similarities in DNA and protein structure support evolution?
Scientists compare the sequence of nitrogen bases in the DNA of different species to infer how closely related the two species are. The more similar the DNA sequences, the more closely related species are.
