BIO220H1 Lecture Notes - Lecture 3: Genetic Drift, Phytophthora, Effective Population Size

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25 Mar 2018

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Yet 3 species account for 60% of food energy intake by humans: rice, maize, wheat. Typically, few genotypes are grown or harvested. Despite this, abundant genetic variation exists in the wild ancestors of feed crops. Severe bottleneck: only a tiny subset of individuals of the wild population are chosen to be cultivated. Strong artificial selection: humans breed and retain the best performing crop plants. Selection on germination timing, seed size, nutrition. H: average frequency of the heterozygous individuals per gene locus. P: proportion of gene loci that are polymorphic. : average number of nucleotide differences per site, for any randomly sampled pair of nucleotides. On what traits did our ancestors select. Case study: domestication of maize from teosinte domestication 10,000 - 5000 ya application of artificial selection before discovery of genetics & natural selection domestication led to dramatic loss of variation. Can we distinguish which loci have lost variation . What do both bottlenecks and selection do.

Related Questions

What is one type of information that can be gathered by archeologists who are studying dental caries (cavities) of ancient populations?

The types of tools used for planting/harvesting grains

How many children the person had

How many conflicts they have been part of

The time of year the person died

The type of plants they may have been consuming

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What is the difference between genetically-modified and transgenic crops?

Transgenic crops are a type of genetically-modified crops, in which scientists have inserted genes from another species.

Transgenic crops are illegal, while genetically-modified crops are not.

Genetically-modified crops are produced using modern techniques, while transgenic crops are produced through classical breeding.

They are the same.

Genetically-modified crops are a type of transgenic crop specifically bred for high yield.

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Vavilov hypothesized that in a crop plant's area of origin we should expect:

Lower genetic diversity than in areas outside of the plant's area of origin.

Greater genetic diversity than in areas outside of the plant's area of origin.

Greater diversity for trans-domesticated species, but lower diversity for species domesticated in their area of origin.

Greater herbivore damage because of increased genetic diversity.

Lower diversity for trans-domesticated species, but greater diversity for species domesticated in their area of origin.

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In what way did Harlanâs theory give rise to Diamondâs theory?

It recognized that agricultural societies were healthier and better fed than hunter-gatherer societies.

It recognized agriculture might have developed by different mechanisms in different parts of the world.

It is a basic case of scientific plagiarism - Diamonds theory is identical to Harlans theory.

It recognized the reason agriculture did not develop in certain parts of the world was because people lacked the intelligence or skill.

Both make the assumption that hunter-gatherers were (and still are) superior to agriculturists.

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What is the difference between classically bred varieties and landraces?

Landraces are grown in dry conditions; classically bred crops are wetland species

Landraces cannot be harvested using domesticated animals; classically bred crops can be harvested using domesticated animals.

Landraces are often (though not always) developed by unintentional processes; classically bred crops are developed by intentionally breeding for desired traits using modern techniques

Landraces are not edible by humans; classical bred crops can be eaten

Landraces have no means of seed dispersal; classically bred crops can readily disperse their seeds

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The inability of plants to move makes it difficult for them to:

Defend themselves.

Disperse seeds.

Create oxygen.

Disperse seeds, defend themselves, and create oxygen.

Disperse seeds and defend themselves.

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Norman Borlaug won the 1970 Nobel Peace Prize for:

Producing the first transgenic plant.

His discovery that plant secondary metabolites play a role in defending plants from insects and diseases.

His work to create improved, high yield crop varieties that helped to prevent starvation.

Creating the FlavrSavr tomato.

His discovery of the area of origin for maize.

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If a plant can grow well all by itself in the wild, yet still retains desirable agronomic traits, the plant is ____________________.

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In discussing the origin of agriculture, the term demographic stress refers to:

A higher incidence of religious practice in societies following the transition from hunting and gathering to agriculture.

Lower productivity of un-cultivated plants due to late-Pleistocene cooling.

Hobbes's assertion that hunter-gatherer groups did not posses the knowledge or skills to develop agriculture.

The situation where human populations are greater than the carrying capacity of the environment.

That the stresses on pre-domesticated plant species led to the development of traits that result in the "domestication syndromeâ

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The repeated domestication of grasses (i.e., cereals) and legumes across the globe is likely because:

Human populations were often starving, and needed an additional food source

Only grasses, not legumes, were repeatedly domesticated

Both contain almost all of the amino acids our bodies need to build proteins.

Early technologies allowed early agriculturalists the ability to communicate with each other over long distances to discuss what plants were best for domestication.

Both already possessed all of the traits needed for domestication

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Which of the following best demonstrates evolution?

A houseplant is moved to a sunnier location and it starts to grow more vigorously.

Your pet walks to the door when it hears your car in the driveway.

A giraffe with a longer neck survives a drought year, while one with a shorter neck does not.

Over time, a gene for disease resistance becomes more frequent in a population of plants.

A crop has a higher yield after fertilizer is added.

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Which of the following types of agriculture can be practiced in an urban setting?

Community gardens

Alternative farms (crickets, caterpillars, other arthropods)

All of these types of agriculture can be practiced in an urban setting

Vertical farms

CSA farms

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______________________ compounds are produced by plants, but are not necessary for the plant's immediate survival. However, they often help protect plants from being eaten.

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Brussel sprouts, cabbage, broccoli and cauliflower are all different varieties of the same species, Brassica oleracea. This group of plants demonstrates that crop breeding can lead to:

High within variety and low between variety diversity

Low within variety and high between variety diversity

Low within variety diversity

High between variety diversity

High within variety and high between variety diversity