BILD 3 Study Guide - Final Guide: Balancing Selection, Genetic Drift, Heterozygote Advantage

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byzantiumfly635

30 May 2016

School

UCSD

Department

Biology/Lower Division

Course

BILD 3

Professor

Sarah Stockwell

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Document Summary

Compare and contrast artificial and natural selection. Explain why not all phenotypic variation is inherited, and the term used to describe phenotypic variation resulting from environmental changes. Be able to give an example of non-heritable phenotypic variation: genotype is the genetic composition of an organism while phenotype is the characteristics of an organism as a result of genes and the environment a. i. Not all phenotypic variation is inherited because some genotypes are also not inherited such as common sense a. i. 1. Phenotypic variation can occur as a result from environmental changes because the environment selects for a better phenotype or by how the environment physically affects a certain phenotype a. i. 1. a. Conservation: staying the same over evolutionary time because changes are harmful a. ii. Purifying selection conserves useful traits: give an example of an allele being beneficial, harmful, or neutral depending on the environment, beneficial a. i. Example: loss of pigments in cave tetra a. i. 1. a. a. ii.

Related Questions

Which of the following states does NOT describe a requirement of natural selection? Question 4 options: Changes in the environment are what prompt organisms to adapt (through natural selection). Only variation in parents' sex cells are passed to their children. Individual organisms adapt to environmental changes via natural selection, not an entire species. Each organism decides what traits are favorable in a given environment.

Corn (maize) was domesticated around 9,000 years ago through artificial selection. Ancient farmers selectively planted kernels from plants with desirable traits, such as bigger kernels, ease of harvest, and better taste. During this time, the wild ancestor of maize, teosinte, has been under natural selection that favors those traits that improve the chance of survival and reproduction in the wild. Maize and teosinte look different in many ways. Assign the following pairs of traits to their respective species by circling the correct response, then provide a hypothesis to explain why these traits were favored during natural or artificial selection in the space allotted.

Trait #1: In (maize or teosinte), the seed is encased in a hard fruit case. This trait may be favored during (artificial or natural) selection because __________________________________. In (maize or teosinte), the seed is exposed. This trait may be favored during (artificial or natural) selection because _________________________________________________.

Trait #2: In (maize or teosinte), the plant has one main stalk. This trait may be favored during (artificial or natural) selection because ___________________________________. In (maize or teosinte), the plant has many branches. This trait may be favored during (artificial or natural) selection because ____________________________________.

Trait #3: In (maize or teosinte), the ear breaks apart to release individual kernels at maturity. This trait may be favored during (artificial or natural) selection because ___________________________________________. In (maize or teosinte), the ear remains intact at maturity. This trait may be favored during (artificial or natural) selection because __________________________________.

2. If both maize and teosinte are grown in the wild, which species is more likely to proliferate? Why?