{ "@context": "https://schema.org", "@type": "Organization", "name": "Brainscape", "url": "https://www.brainscape.com/", "logo": "https://www.brainscape.com/pks/images/cms/public-views/shared/Brainscape-logo-c4e172b280b4616f7fda.svg", "sameAs": [ "https://www.facebook.com/Brainscape", "https://x.com/brainscape", "https://www.linkedin.com/company/brainscape", "https://www.instagram.com/brainscape/", "https://www.tiktok.com/@brainscapeu", "https://www.pinterest.com/brainscape/", "https://www.youtube.com/@BrainscapeNY" ], "contactPoint": { "@type": "ContactPoint", "telephone": "(929) 334-4005", "contactType": "customer service", "availableLanguage": ["English"] }, "founder": { "@type": "Person", "name": "Andrew Cohen" }, "description": "Brainscape’s spaced repetition system is proven to DOUBLE learning results! Find, make, and study flashcards online or in our mobile app. Serious learners only.", "address": { "@type": "PostalAddress", "streetAddress": "159 W 25th St, Ste 517", "addressLocality": "New York", "addressRegion": "NY", "postalCode": "10001", "addressCountry": "USA" } }

Lecture 8: Evolution Across Space Flashcards

(36 cards)

1
Q

What is gene flow in simple terms?

A

Mixing of alleles between different populations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a cline?

A

A smooth transition in a trait across geographical space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is clinal variation?

A

gradual changes in a trait or characteristic of a species across a geographic area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Cline vs clinal variation

A

a cline is the concept of gradual change, while clinal variation is the actual observed variation in traits across different geographical locations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does clinal variation relate to white clover plants?

A

Some plants have high frequency for an allele that causes deletion of the gene that produces cyanide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is Bergmann’s rule?

A

Body sizes of mammals and birds tend to increase with distance from the equator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why do animals in cold climates have less heat loss?

A

larger body size –> lower surface to volume ratio

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Are moose larger in Northern or Southern Sweden?

A

Northern

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the Wales mine and common bent grass situation an example of?

A

Local adaptation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Did adult common bent grass or common bent grass grown from seed have higher copper tolerance near the mine?

A

Adult

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happened to tolerance of copper as distance from the mine increased?

A

Decreased

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

When do clines evolve? (2 answers)

A

1) When selection pressures change across space

2) When there is gene flow between populations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the two important roles of gene flow in evolution?

A

1) Makes populations more similar

2) Introduces new alleles into a population from other populations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What causes gene flow?

A

Dispersal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is dispersal?

A

Movement of individuals or gametes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What affects the ability of toucan subspecies to disperse?

17
Q

What is migration rate (m)?

A

the fraction of individuals arriving from another population each generation

18
Q

Basically, m is a measure of …

A

how quickly gene flow erodes genetic differences between populations

19
Q

What is the equation for the change in allele frequency before and after migration? What do the variables stand for?

A

∆p = m(pₘ – p)

∆p: change in allele freq b/c of migration
pₘ: allele frequency in migrants
p: allele frequency in recipient pop
m: migration rate

20
Q

When is migration variance (σₘ^2) used?

A

When there are no distinct populations and thus the populations are spatially continuous

21
Q

What does σₘ represent?

A

The average distance between birthplace of a parent and its offspring

22
Q

What does a variance of zero mean?

A

Measurements are all identical

23
Q

Larger variance means (more/less) dispersal

24
Q

Can variance ever be negative?

25
What is Fₛₜ and what does it measure?
Fixation index statistic, measures the fraction of total genetic variance across two or more populations resulting from genetic differences between them
26
Fₛₜ = 0 means ...
two populations are identical
27
Fₛₜ = 1 means ...
two populations are fixed for different alleles
28
Fₛₜ = 0.36 means ...
36% of all the genetic variation in the two populations is caused by the differences among them
29
As the distance between pairs of populations increases, Fₛₜ ___
increases
30
selection and gene flow act ___ of each other
opposite
31
What would happen to allele frequencies if there was no selection or drift?
Gene flow would make allele frequencies uniform
32
Gene swamping
When gene flow overwhelms local adaptation
33
What can width of cline be used to measure?
Strength of selection
34
What happens to the cline as the migration variance increases?
Changes in allele frequency are less abrupt, so the cline becomes flatter
35
If selection is stronger than gene flow, then the cline becomes ____
steeper
36
Clines that form when there is selection against heterozygotes are very ___. Why?
narrow. Heterozygotes have reduced fertility