Unit 8 Evolution Study Guide Flashcards
Define “evolution”.
The process of change over time
Define “theory” in scientific terms.
A Well supported explanation
Who is Charles Darwin, and why is he important?
He was a biologist & naturalist (someone who studies the natural world) and had always been interested in biological diversity
What 3 patterns of biological diversity did Darwin observe?
Species vary globally - He saw that species differed in different parts of the world
Species vary locally - Related species often live in different habitats within a local area (and may look different)
Species vary over time - Darwin saw fossils that showed some extinct species were similar to living ones, while others were unlike anything he had ever seen.
Where did Darwin do most of his famous research?
Galapagos Islands
Describe the importance of Darwin’s finches.
Beak size differed depending on the island that they were on. All were the same species of birds, but they had changed over time to adapt to their habitat!
In Darwin’s time, how old did people believe the Earth was?
A few thousand years old
_______ ________ concluded that the Earth must be much older than most believed - he coined the term “ ______ _______” which means “much older than we can imagine”.
James Hutton
deep time
________ ________ built upon Hutton’s work and demonstrated that Earth processes have _______ changed the Earth over _______ ________
Charles Lyell
slowly
many years
What are Jean-Baptiste Lamarck’s 2 major hypotheses about evolution?
Use/disuse: organisms could change the shape/size of organs by not using them (acquired characteristics)
Inheritance of acquired characteristics: traits acquired over one’s lifetime could be passed to offspring
Thomas Maltus noted three major forces that worked against population growth. These 3 forces were:
War
Famine
Disease
What 2 ideas did Darwin draw from Malthus’s ideas?
More offspring are produced than can survive
Not all who survive will reproduce
What is artificial selection?
process used by breeders and farmers to enhance the traits they want
What did artificial selection demonstrate to Darwin?
This showed him that traits could be inherited and that variation between organisms is important.
Explain each of Darwin’s 3 main ideas:
Struggle for existence - not all individuals survive because of competition (food, water, space, etc.)
Natural variation - Individuals with the best natural variation will most likely survive. Examples of this are: birds with brighter feathers, moth wing patterns
Fitness -an individual’s ability to survive and reproduce.
Define adaptation
Heritable traits that increase an organism’s ability to survive and reproduce
Summarize the phrase “survival of the fittest”.
Individuals with higher fitness will survive and reproduce most successfully.
What are the 4 steps that lead to natural selection?
Struggle for existence
Natural Variation
Survival of the fittest
Changing population (fitter organisms become more common)
Darwin proposed that all living things may have originated from a single “ ________ ________”. He termed this ___________ with ___________
“common ancestor”.
descent
modification
Explain how fossils can be used as evidence for evolution.
Compare fossils from older layers of rock to newer layers to see changes
What is “geographic distribution” and how does it provide evidence for evolution?
Comparing animals from all over the world
-Organisms in the same area tend to look similar (even if they aren’t the same species)
-Same species living in different places may look very different (likely facing different evolutionary pressures)
What are homologous body structures and how do they provide evidence for evolution?
Structures shared by related species (and have been inherited from a common ancestor)
-More similar=more closely related
What is a vestigial organ?
Organs that serve no purpose but do not disappear because they do not put individuals at a disadvantage
What is embryology and how does it provide evidence for evolution?
Embryos of different species develop in a similar pattern to produce tissues & organs found in all vertebrates
🡪Common ancestor
What is molecular evidence and how does it provide evidence for evolution?
Molecular Evidence (DNA, RNA, Amino Acids)
Using DNA comparison to determine relatedness.
The closer the DNA sequence, the more closely related
Define “gene pool”.
All genes present in a population
Define “relative frequency”
of times allele occurs compared with # of times the other alleles occur (%)
Define “gene shuffling”
Genes are mixed up during gamete production
