Class 03 W16 - Dr. Jacobs and Dr. Newmaster\'s lecture on mussels and evolution PDF

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Dr. Jacobs and Dr. Newmaster's lecture on mussels and evolution...

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1/18/2016

Which of the following contributes to the extraordinary success of dreissena in the great lakes region?

Zebra mussels don’t use the gill glochidia technique

David Attenborough, Life in the Undergrowth

BIOL*1070 Class 03

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1

Learning outcomes to recognize the kinds of factors (both external and internal) that influence a species’ success or peril under particular conditions.

1/18/2016

stand the major levels of biological organization and the nature and importance of variability at each of them. m some basic data collection and analysis and consider sources of error in a dataset.

2

Inquiry Case 1 Unit 2 Invasion! Mussels of the Great Lakes region

D

The Learning Team:soProfessors What do we know far?

the following contributes the most to the extraordinary success of Dreissena polymorpha in the l run-off eliminating competitors. nd exhalent siphons for filter-feeding. arvae and host-attraction specializations. vae that disperse freely. bivalve shell.

The Learning Team: Professors

DNA comes from nucleus of the mitochondria, chloroplast Variation- mutations, natural selection

Mini lecture: Variability at multiple biological scales

The Learning Team: You and Your Peers!

Traits= alleles- fixed, wont change

Genetic variation: Causes and consequences Genetic variation = differences at the DNA level among individuals within a population or species. Alleles = Different versions of the same gene. Genetic variation can change within populations in various ways: Mutation, natural selection, genetic drift, gene flow. The primary source of genetic variation is mutation. Can also result from recombination. Mutations are errors in DNA replication. They occur at random. Mutations do NOT occur in order to benefit the organism.

Genome duplications can be done on dandelions

The Learning Yousource and Your Peers! variation Mutation: TheTeam: primary of genetic Various kinds of mutation:

Name

Description

Point mutations

Base pair substitution in DNA sequences

Chromosome Rearrangement or fusing of chromosome mutations

Gene duplications

Genome duplications (polyploidy)

segments; alter gene order Duplication of a short stretch of DNA, creating an additional copy Addition of a complete set of chromosomes

Cause Chance errors during synthesis or repair of DNA

Significance Create new alleles

Breaks in DNA Change proximity caused by radiation of genes to each or other factors other and to regulatory regions Unequal crossingAllow duplicate over during meiosis genes to diverge in function Hybridization or errors in meiosis or mitosis

Duplicate all genes; can create new species

The Learning Team:Non‐random You and Yoursurvival Peers!and reproduction Natural selection:

d/or reproduction among individual entities on the basis of differences in heritable characteristics. (Did I mention that natural selection is, by definition, NON‐RANDOM?) (More about natural selection next week)

The Learning Team: You and Your Peers!

Same species but different alleles giving rise to red or blue bugs The result in shift of red:blue is genetic drift

Genetic drift: Evolution by chance due to sampling error The Learning Team: You and Your Peers!

Before: 50%

After: 29%

50%

71%

Bottleneck: Evolution by chance due to random event The Learning Team: You and Your Peers!

Cause of genetic drift #2: Founder effects

Bottleneck- an event that causes a large deletion of a section of a species/population- less diversity between individuals (tornado, hurricane etc) Mainland has big population Individuals from mainland move over to the island bringing specific genes, possibly bringing rise to a new species as not all genes of the species are accounted for (over time of course)

Mainland: 50%

50%

Founder: 29%

71%

Over time, the allelic variation changes as individuals move from region to region Similar to migration

After:

36%

64%

After:

50%

50%

Gene flow: Movement of genes among populations SAMPLE EXAM QUESTION:

Before: 27%

73%

Before: 100%

0%

Clicker Question (sample exam question) careful study of DNA sequences reveals that a population of mussels in a particular river has very little genetic va hich of the following explanations would you REJECT? ere has been intense natural selection favouring individuals with a particular trait. ere has been a great deal of movement of mussels into this river from nearby lakes. severe storm once left only a few survivors in this population. is species of mussel has remarkably efficient DNA repair enzymes. is population was established by only a few larvae that were carried into the river by a fish host.

Active Learning Identifying a Specimen

Figure it out ?? discussion B

The Learning Team: You and Your Peers!

Could be a mistake in the book Mutations Invasive species

Active learning: Identifying a specimen If you worked for Fisheries and Oceans Canada and found a mussel shell in a river, how would you go about identifying it quickly and accurately? The Learning Team: You and Your Peers!

?

Active learning: Identifying a specimen

Activity:

Working with a small group of colleagues, use your field guide to identify your specimen.

Write down the number on the shell and your proposed identification (common name, species name, field guide page #).

These shells are the property of the Department of Integrative Biology and were collected under permit. Many of them are endangered. It is illegal to possess these shells without a permit. So please BE CAREFUL and BE SURE TO RETURN THEM!

The Learning Team: You and Your Peers! Clicker question was the biggest challenge to getting a correct identification? (Choose one) owed it down to a few species, but variation in characters within species made it hard to choose one. cimen lacked one of the key characteristics we expected for that species and/or had one normally found in another species. cimen was damaged, dirty, immature, or the wrong part of the shell. rmation in the field guide was not organized in a straightforward way (i.e., no taxonomic key). e were awesome and got it right easily.

The Learning Team: Professors

Clicker Question (sample exam question) Which of the following is TRUE with regard to the mussels having veliger vs. glochidia larvae?

The Learning Team: You and Your Peers!

HOMEWORK: Random?

Genetic variation Increase? Decrease? Same?

Resulting number of populations

Genetic difference among populations Increase? Decrease? Same?

Genetic drift – Bottleneck

yes

decrease 1

decrease

Genetic drift – Founder effect

yes

decrease 2

decrease

Gene flow

yes

decrease 1

decrease

Mutation

yes

increase 1

Increase

Natural selection

no

decrease 1

decrease...