Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
36 Cards in this Set
- Front
- Back
|
the Earth is how old?
|
12 to 20 billion years old
|
|
|
Cambrian explosion
|
era where multicellular bodies formed
|
|
|
Define Evolution
|
a change in gene or allele frequency in a population over time
|
|
|
Sources of Variation on Evolution
|
1) Mutations
2)Dominance/Recessive 3) Independent Assortment 4) Changed Environment 5) Balanced Polymorphism |
|
|
Balanced Polymorphism
|
more than one allele for a trait - that is steady in the population
ex: ABO blood types |
|
|
Genetic Drift
|
The random change of the occurrence of a particular gene in a population
|
|
|
Bottlenecks
|
a random environmental disaster that reduces a population to near extinction and reduces genetic diversity
|
|
|
Gene flow
|
the immigration or emigration of individuals between small populations resulting in the loss of gain of genetic diversity
|
|
|
Founder effect
|
the first member/group of a species to invade a new territory will have less genetic diversity than the species as a whole
|
|
|
Macro VS Microevolution
|
Macro - long term genetic changes
Micro - changes in gene/allele frequencies within a population or species |
|
|
Patterns of Selection
|
1) Stabilizing
2) Directional 3) Disruptive 4) Sexual |
|
|
Stabilizing
|
preservation of the mean characteristic
|
|
|
Directional
|
continuous selection for one extreme of a characteristic
|
|
|
Disruptive
|
simultaneous selection for both extremes of a population trait in two different environments
|
|
|
Sexual
|
selection based on mating prefrences
|
|
|
Types of Isolation
|
1) Behavioral
2) Temporal 3) Ecological 4) Mechanical 5) Postzygotic |
|
|
Behavioral Isolation
|
distinct courtship rituals
|
|
|
Temporal Isolation
|
distinct mating seasons
|
|
|
Ecological Isolation
|
alternate use of environmental materials which minimizes contact and competition
|
|
|
Mechanical
|
Incompatible reproductive organs
|
|
|
Postzygotic Isolation
|
embryos formed are nonviable or offspring are sterile
|
|
|
Patterns of Evolution
|
1) Divergent
2) Parallel 3) Convergent |
|
|
Divergent
|
different species develop from a common ancestor; have homologous structures - parts with common origins but now perform different functions
|
|
|
Parallel
|
selection pressure moves two distinct groups along relate paths
|
|
|
Convergent
|
two different groups come to the same solution and look or act alike; have analogous structures - parts that look or act alike but are derived from different components
|
|
|
Gradualism
|
new species emerge through many small changes in form over long expanses of time
|
|
|
Speciation
|
the process by which species originate
|
|
|
Adaptive Radiation
|
a burst of speciation events, in which they move away from one another due to environmental factors
|
|
|
What two molecules were not present on early Earth?
|
oxygen and water
|
|
|
Punctuated equilibrium
|
a theory of evolution which states that changes such as speciation can occur relatively quickly, with long periods of little change in between
|
|
|
Homo habilis
|
most ancient of the human species
|
|
|
Types of Proteins
|
enzymes and structural proteins
|
|
|
Genetic defects in structural proteins tend to be inherited
|
dominantly
|
|
|
Genetic defects in enzymes tend to be inherited
|
recessively
|
|
|
Consequences of defective enzymes:
|
1) "Downstream" - products are not produced
2) "Precursor" - chemicals are not used or built up |
|
|
Define Mutations
|
Mutations are any heritable change in the DNA code
|
