Phylogeny
What is the definition of a clade?
A clade consists of a most recent common ancestor and ALL of its descendants.
Define the terms macroevolution and microevolution.
Macroevolution- evolution of new taxonomic groups, also includes mass extinctions and similar events
Microevolution- change in allele frequencies IN A POPULATION over time
Which of the following is evidence for evolution occurring?
fossil record
comparative anatomy
geographic distribution of organisms
all of the above
4. All of the above!
An organism with a gametophyte dominant life cycle, lack of vascular tissue, moist habitat and reproduction via spores would be classified as:
a fern
a moss
a horsetail
a gymnosperm
2. a moss
You are scuba-diving and you see an organism with a hinged shell and what looks like a tongue sticking out. It looks to be bilaterally symmetric. It is most likely which of the following?
1. a mollusk
2. a bivalve
3. a gastropod
4. 1 and 2
5. 1 and 3
6. all of the above
4. 1 and 2
Two taxa are sister when...
they share an immediate common ancestor.
These are the two ways that new traits arise.
Mutation and sexual reproduction
Which of the following suggest shared ancestry?
1. Homologous structures
2. Analogous structures
3. Similarities in embryo development
4. 2 and 3
5. 1 and 3
5. 1 and 3
You stumble upon a knee-high plant lacking flowers in a shady, wet part of the forest. You notice brown, spore-producing structures on the undersides of its leaves. What kind of plant do you think it is, and why?
Seedless vascular plant- tall, so has vascular tissue, lacks flowers, in a moist area (most likely because ti is necessary for reproduction), produces spores
Which of the following are both in the phylum Cnidaria?
1. sponges and jellies
2. sea stars and corals
3. sea cucumbers and sponges
4. corals and jellies
4. corals and jellies
A polytomy is...
An unresolved pattern of divergence
You have a population of mice whose genotypes are: Bb, BB, BB, bb, Bb, BB, Bb, Bb, BB, Bb. Answer the following questions: How many individuals in the population? How many alleles does each individual have? How many alleles in the population? What is the frequency of the B allele? Of the b allele?
10 individuals in the population, 2 alleles for each individual, 20 alleles in the population, B allele frequency: 13/20 ~ 0.65, b allele frequency 7/20 ~ 0.35.
True or false?: The only evolutionary mechanism that results in organisms well-suited to their environment is gene flow.
You are looking under a microscope and see a few small, pill-shaped organisms. You leave it there and return 20 minutes later, only to see many more pill-shaped organisms. You are most likely observing a _______.
prokaryote
Land-dwelling arthropods developed a hard exoskeleton on the outsides of their bodies to provide protection and support as well as to prevent water loss. This is similar to which characteristic(s) developed by plants?
1. vascular tissue
2. seeds and pollen
3. cuticle
4. 1 and 3
5. 2 and 3
4. 1 and 3
What traits can we use to construct a phylogeny? There are three.
DNA sequencing, morphology, biochemistry
You have a population of 40 milkweed plants in your greenhouse. Aphids then begin to attack your plants, leaving you with only 10 milkweed plants. This is an example of which cause of evolution? What do you expect to happen to rarer alleles in the population?
This is an example of genetic drift, more specifically: bottlenecking. The rarer alleles are more likely to be eradicated from the population.
Explain what fitness means in the context of evolution by natural selection.
An individual who is fit has traits that increase their likelihood of surviving to reproduce and pass their traits to the next generation.
Hornworts and mosses are different from liverworts in that:
they have stomata, whereas liverworts have pores
they have pores, whereas liverworts have stomata
they are not different from each other; they all have pores
they are not different from each other; they all have stomata
1. they have stomata, whereas liverworts have pores
You are in your basement and find a long worm-like creature with a hard segmented exoskeleton and two pairs of legs per segment. It is most likely:
1. an arthropod
2. an insect
3. a centipede
4. a millipede
5. 1 and 3
6. 1 and 4
7. 3 and 4
With your team, draw a phylogeny and label the following: a node, sister taxa, a polytomy, and a clade.
Answers vary--see notes if you are having trouble with this!
Which mechanism(s) of evolution result(s) in allele frequencies that are different from those of the original population?
Bottlenecking and Founder effect
Two populations of mice are separated by a large stretch of deciduous forest. A mouse from one of the populations gets lost and finds the other population of mice. This is an example of ________.
Gene flow.
You are watching a fish at an aquarium. It breathes with gills and has fan-like fins that do not look to be very muscular. You are likely observing a _______.
Ray-finned fish
You are dissecting a worm. You notice that it has no segments. You cut it open and notice that it has a coelem. It is most likely a(n):
1. flatworm
2. segmented worm
3. earth worm
4. roundworm
5. 1 and 4
6. None of the above
4. roundworm