Exam 2 Flashcards
Evolution
change in the heritable characteristics of biological populations over successive generations
What are the 5 mechanisms of evolution?
- mutation
- non-random mating
- gene flow
- genetic drift
- natural selection
Natural selection, what is it?
- variation must exist (the population differs from one another with respect to a trait)
- traits must be heritable (trait differences are, at least in part, passed from parent to offspring)
- differential reproduction (variation in the traits renders some individuals more successful at surviving and reproducing than others)
What is differential reproduction?
variation in the traits renders some individuals more successful at surviving and reproducing than others
Selection happens to _____, but what changes is ______. Individuals do not ______.
individuals, populations, evolve
Who were the two authors that discovered natural selection before Darwin and Wallace?
W.C. Wells and Patrick Matthew
Which of the 5 mechanisms of evolution are predictable?
natural selection
How long ago did the finches that Darwin’s finches descend from invade the archepelago?
2-3 million years ago
What type of food do woodpecker and mangrove finches eat?
use twigs or cacti spines as tools
What type of food do vegetarian finches eat?
leaves and fruit
What type of finch did Grant and Grant study, and where?
medium ground finch on Isla Daphne Major
How long can the medium ground finches live for?
16 years
What is the generation time of the medium ground finches?
4.5 years
What do medium ground finches primarily eat?
Seeds
Is the finch population variable?
yes
What protein is responsible for beak depth?
Bone morphogenic protein 4
When does natural selection change?
when the environment changes
Large birds are favored in _______ years, small birds are favored in _____ years.
drought, wet
Natural selection acts on phenotypes, but evolution consists of changes in _____ frequencies.
allele
Natural selection is forward-looking, and occurs regardless of the environment. True or False?
False, natural selection is not forward-looking and only reacts to the environment.
Selection only acts on:
existing traits
What type of traits are often lost?
complex
Why are phylogenies useful?
- to understand evolutionary relationships between taxa
- to ask questions related to the origin on adaptations
- to help define taxonomy
Derived traits
traits that differ from common ancestor
What is the first thing you should identify when constructing a tree?
the individuals with the most unique characteristics
What does it mean when a characteristic is unique to one/a few individuals?
the trait must have evolved more recently
Paraphyletic group
a group consisting of an ancestor and some, but not all of its descendants
Fitness
an individual’s ability to survive and reproduce
Adaptation
a trait that increases an organism’s fitness relative to individuals lacking it
Is there any conscious intent with natural selection?
no
What was the premise of Jones’ and Reithel’s experiment in 2001?
If color preference by bumblebees could drive the evolution of flower color in snapdragons
What type of food do Warbler finches eat?
insects, spiders, nectar
What type of food do geospiza finches eat?
ticks from iguanas and tortoises, seeds
Is some of the variation in beak depth heritable?
yes
Natural selection acts on individuals, where does the consequence of this occur?
in the popluation
Natural selection does not generate new genetic variation. What does?
mutations
Evolution results in individuals that are perfect. True or False?
false
Is natural selection predictable? Does this mean selection is random or non-random?
predictable, thus non-random
Is natural selection progressive?
no
Phylogenies
hypothesis about evolution from a common ancestry to several descendent lineages
Who was the first known phylogeny drawn by?
Darwin
What type of data is used to construct phylogenies?
genetic info and phenotypic traits
Trees always start from a _____ ancestral lineage.
single
Polytony
a branch where you are unable to determine who is more related to who
any tree contains only:
what the marker deemed relevant to the analysis
Trees will always reveal a truth. True or false?
False, trees are a hypothesis based on data
Apormorphy
“separate form” - a derived character
Plesiomorphy
“near form” - an ancestral character, trait that the common ancestor had
Synapomorphy
“similarly separate form” - a derived character shared by two or more lineages
Monophyletic groups
clades - consists of an ancestor and all of its descendants
What identifies monophyletic groups?
synapomorphies
Polyphyletic group
a group that contains some, but not all of an ancestor’s descendants, and that also excludes the ancestor
Since 1980, how many finches have been marked in Grant and Grant’s experiment?
100%
