Learning Guide 18 Flashcards
What is the relationship between a population and a species?
A group of individuals of a species live in a population
What is the definition of a population?
A group of individuals of a species that live in a particular area
What are four variables that govern changes in population size?
Births, deaths, immigration, emigration
What are factors that affect the size of a population?
Biotic potential and environmental resistance
What is biotic potential?
Factors that favor increase in population size
What is environmental resistance?
Factors that favor decrease in population size
What is carrying capacity?
The maximum size of a population that a particular environment will support
What are the two main types of growth exhibited by populations?
Logistic growth and exponential growth
Are there always limits to population growth in nature?
Yes
Is carrying capacity the same for all populations and all environments?
No
Describe Type I survivorship curve.
- Little mortality in the early part of the lifespan
- Majority of individuals survive to reach reproductive age
- Greatest amount of mortality occurs in later portion of lifespan
Give examples of organisms that exhibit Type I survivorship curve.
Humans, elephants, polar bears
Describe Type II survivorship curve.
The probability of dying is the same at any time during organism’s lifespan
Describe Type III survivorship curve.
Majority of mortality in the early part of the potential lifespan, small percentage of initial number of individuals survive to reproductive age
Examples of organisms that exhibit Type III survivorship curve
Insects, annual plants, oysters
What phrase did Darwin use originally instead of the term evolution?
descent with modification
Name the three key observations that support Darwin’s theory of evolution.
All species produce more offspring than the environment can support, individuals of a population vary in their traits, organisms’ variations can be inherited by their offspring
What is the mechanism for evolution?
Natural selection
What is natural selection?
Differential or unequal success and reproduction
What is artificial selection?
The opposite of natural selection, humans select desired characteristics
What is the smallest unit that can evolve?
Population
What is Hardy-Weinberg equilibrium?
No change in frequencies of alleles in gene pool, no microevolution
What is microevolution?
Change in the gene pool, studied by looking at frequencies of alleles
What five conditions are necessary for Hardy-Weinberg equilibrium to be maintained?
Population is very large, population is very isolated, gene mutations cannot occur, mating is random, all individuals are equal in reproductive success.
