Unit 7 check
Unit 7 check: Natural Selection
12 questions from 12 lessons in Unit 7. Answer each one, and if you miss, follow the link back to where it is taught, then try again. Your score counts first tries.
Question 1 · from 7.1 · Put it in order
A population of seed-eating mice lives in a field where the seeds run short each winter. Put these events in the order they happen as natural selection acts on the population, ending with the population that results.
Question 2 · from 7.2 · Sort it
Each card names a variation and the environment an organism lives in. Tap a card, then whether the variation is more likely to raise or lower fitness in that environment.
More likely to raise fitness
More likely to lower fitness
Question 3 · from 7.3 · Sort it
Each card describes what decides which individuals reproduce. Tap a card, then the kind of selection it describes.
Artificial selection
Natural selection
Question 4 · from 7.4 · Sort it
Each card describes a change in a population of fish. Tap a card, then whether it shows the population evolving.
Shows evolution
Does not show evolution
Setup for question 5
Two snail populations, both teaching examples. For the first, you are given the count of each genotype and find an allele frequency from them. For the second, you are given an allele frequency and use the equations to predict how many snails of one genotype to expect.
Question 5 · from 7.5 · Calculate
A second population of 1,000 snails is in Hardy-Weinberg equilibrium, and allele b has a frequency of 0.3. How many snails would you expect to be heterozygous, Bb?
Setup for question 6
Two new cases. In the first, a protein compared between two species is turned into the percentage of positions that match; the numbers are a teaching example. In the second, you decide whether the reduced eyes of fish that live in dark caves are evidence that they share an ancestor with fish that live in open water.
Question 6 · from 7.6 · Decide and justify
A species of fish that lives in dark caves has small eyes, covered by skin, that do not work. A closely related species that lives in open water has eyes that work. Are the cave fish's eyes evidence that the two species share a common ancestor?
Which statement supports your decision?
Setup for question 7
A lab examines five single-celled organisms, V to Z, for three features. These organisms are a teaching example.
| Organism | Membrane-bound organelles | Chromosomes | Genes with introns |
|---|---|---|---|
| V | Yes | Linear | Yes |
| W | No | Circular | No |
| X | No | Linear | No |
| Y | Yes | Linear | Yes |
| Z | No | Circular | No |
Question 7 · from 7.7 · Decide and justify
Using the table: a student says organism X is a eukaryote because its chromosomes are linear. Is the claim well supported?
Which statement supports your decision?
Setup for question 8
Researchers test mosquitoes from two regions with the same dose of an insecticide, a kind of pesticide, every two years. One region was sprayed with the insecticide every year; the other was never sprayed. The numbers are a teaching example.
| Year | Sprayed region (%) | Unsprayed region (%) |
|---|---|---|
| 0 | 3 | 3 |
| 2 | 9 | 4 |
| 4 | 24 | 3 |
| 6 | 51 | 4 |
| 8 | 81 | 3 |
Question 8 · from 7.8 · Decide and justify
Using the table: a student suggests the rise in the sprayed region was caused by a change in weather over the eight years that affected both regions alike. Do the data support the student's idea?
Which statement supports your decision?
Setup for question 9
A biologist scores four lineages, A to D, and an out-group for four traits. A yes means the lineage has the trait. The data are a teaching example.
| Lineage | Trait 1 | Trait 2 | Trait 3 | Trait 4 |
|---|---|---|---|---|
| Out-group | No | No | No | No |
| A | Yes | No | No | No |
| B | Yes | Yes | No | No |
| C | Yes | Yes | Yes | No |
| D | Yes | Yes | Yes | Yes |
Question 9 · from 7.9 · Decide and justify
Using the table: a student says lineage A is more closely related to the out-group than to lineage B, because A and the out-group both lack traits 2, 3 and 4. Is the student right?
Which statement supports your decision?
Question 10 · from 7.10 · Spot the error
A student explains why sharks and dolphins both have a streamlined body shape. Tap the line with the mistake.
Question 11 · from 7.11 · Multiple choice
Two populations of the same species of tree are the same size. In population X, the trees carry many different alleles at most genes; in population Y, nearly all the trees carry the same alleles. Which population is more at risk of decline from a change in its environment, and why?
Question 12 · from 7.12 · Sort it
Each card states a claim about early life. Tap a card, then whether it is one of the assumptions of the RNA world hypothesis.
An assumption
Not an assumption
0 of 12 answered.