BLG 144 Lecture Notes - Lecture 11: Net Reproduction Rate, Fecundity, Exponential Growth

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greendolphin637

5 May 2015

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Population: group of individuals from the same species that live in the same area at the same time population ecology: the study of how and why the number of individuals in a population changes over time. Number of individuals present in a population depends on: Births and immigration: add individuals to the population. Deaths and emigration: remove individuals from the population. Demography: study of factors that determine the size and structure of a population over time. Generation: the average time between a mother"s first offspring and her daughter"s first offspring. Life tables are used to summarize the probability that an individual will survive and reproduce in any given time interval over the course of its lifetime. Survivorship: proportion of offspring produced that survive to a particular age. Cohort: a group of the same age that can be follow through time ex: 1000 babies born that year. Survivorship curves: log (number of survivors) vs. age.

Related Questions

Suppose a starting population contained six individuals. Each pair of individuals had a different genetic makeup (genotype) from the others (genotypes: G-1, G-2, and G-3). The genotypes vary with respect to reproductive rate and offspring survival. Suppose G-1 has 8 offspring that survive to reproduce, G-2 produces only 4 surviving offspring over its lifespan, and G-3 leaves 12 surviving offspring.

a) If the average individual produces 8 offspring by the end of its lifespan, will the reproductive differences among genotypes alter the population growth rate?

b) How would the reproductive differences among genotypes alter the genetic composition of the population by T9? And by T500? (Assuming at T0 we start with one individual of each genotype.)

c) Suppose that the genotypes have the same birth rates as shown above at low density, but genotypes 1 and 3 experience greater effects of density dependence on birth rate than 2. What might happen to the relative frequency of this genotype by T500?

graycicada41

1. Traits don't necessarily have to be passed on from parent to offspring for natural selection to act on them; traits that are environmentally acquired during the life time of an individual (such as practicing to become very strong or very fast) can also be acted upon by natural selection. Select one: True or False

2.Within the same species and even within the same population, not all individuals are the same. They vary in size, shape or other traits.

Select one:

True

False

3.Differential reproductive success means that some individuals in a population leave more offspring that survive and reproduce relative to other individuals in a population.

Select one:

True

False

coraldolphin670

In a large population of an annual wild pea species, height is controlled by a single locus; DD and Dd individuals are tall, while dd individuals are short. Because the local environment is very windy, tall plants tend to get broken and survive to reproduce only half as well as well as do short plants. Mating is random with respect to height and there is no immigration or emigration. In a population of 21,000 (large enough to be considered infinite for the purposed of the Hardy-Weinberg equilibrium and natural selection models; assume this population size remains constant through the generations described in this question) adult pea plants that successfully reproduce after natural selection through differential survival has occurred, there are 7,000 DD individuals, 7,000 Dd individuals, and 7,000 dd individuals.

a) What will be the frequency of the D allele in the gametes (sperm, in pollen, and ovules) that will unite to make up the next generation?

b) What will be the genotype frequencies of DD, Dd, and dd in the seeds that are formed to start the next generation? How many seeds will there be with each genotype?

c) What will be the genotype frequencies of DD, Dd, and dd in the adults that develop from these seeds and survive to reproduce? How many adults will there be with each genotype?

d) Over a long period of time, what do you expect to happen to the D and d alleles in this population? Why?

BLG 144 Lecture Notes - Lecture 11: Net Reproduction Rate, Fecundity, Exponential Growth

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