Bio 114 Unit 3 Flashcards
How old is the earth?
over 4.5 billion years old
How long has some form of life been present?
over 3 billion years
Who was the first person to develop a scientific theory of evolution?
Lamarck
Compare Darwin and Lamarck
Both thought species could change overtime
Contrast Darwin and Lamarck
Lamarck thought organisms could pass to their offspring features gained through use of exercise
Darwin didn’t have this mistaken view of inheritance
What analogy did Darwin use to illustrate “decent with modification”?
Tree of life
Individuals don’t ______ __________ __
…evolve, populations do
What is the first degree of adaptation? what is it measured by?
Fitness; individuals’ relative genetic contribution to the future generations; high evolutionary fitness > produce more offspring
What is stabilizing selection?
form of selection that eliminates “oddballs” and extreme individuals; reduces variation and keeps everybody close to average
What do scientists think about 4-limbed vertebrates?
They share similar limb structures because they inherited the same basic design from a common ancestor
Some features of humans have no clear function. What does evolutionary thinking think?
these structures are vestigial features, inherited from ancestors in which that structure WAS a valuable adaptation
Humans, lizards, birds, whales, and other 4 limbed vertebrates have a similar limb structures with…
…a bone at the base, then a pair of bones, then a mass of wrist or ankle bones, and finally 5(or less) digits
vertebrate limbs are the most familiar example of …
…a homologous structure
Pterodactyls and bats both have wings formed by a membrane stretched out between long limb bones. But bats and pterodactyls are not…
…closely related and their common ancestor was a sturdy land-dwelling reptile; their similar wings are analogous structures
Many life forms are restricted to the Southern Hemisphere continents of South America, Africa, Australia, and sometimes India, but…
…there are many fossil groups that indicate they were once on other continents. Scientists trace these Southern-Hemisphere groups to the ancient supercontinent of Pangaea
The transition of Elephants in one part of Africa into having bigger ears is an example of…
…microevolution
What was one thing that inspired Darwin’s Theory of Adaptation? What is this called?
His observation that humans could create spectacular varieties of dogs, cows etc. through selective breeding; Artificial selection
Two main sources of Variation in Populations?
Mutation and Sexual Reproduction
How can mutations be?
Harmful, helpful or have no effect on an organism and are not always reduced by Natural Selection.
Sickle shaped Hemoglobin in Red Blood Cells can cause…
…people to die from Sickle Cell Anemia, but are not protected from Malaria. The Allele that causes Sickle Cell Anemia in Homozygotes is maintained in some human populations because the Sickle Cell Allele protects Heterozygotes (carriers) against malaria
What are heritable traits that enhance an individual’s Fitness?
Adaptations; they work well in the population’s normal environment, but have limits and may not be suitable for environmental changes
Process that includes some random elements (mutation) and other predictable elements (Inheritance, selection)
evolution
What is the purpose of the PreBiotic experiment?
Demonstrate the origin of life using conditions of early Earth
What is considered the most dominant (abundant) organism living on earth?
Prokaryotes
