Exam 2 Flashcards
What is character displacement?
When two similar species start to disperse in the same geographical area. They are forced to evolve through natural selection due to limiting resources. Similar species require the same resources and the increased competition will cause character displacement. An example would be galapgos finches as their beaks and body size changed over time.
What is an r-selected species?
R-selected species are species that produce large numbers of offspring with high growth rates and low probability to survive adulthood. R-species live much shorter on average compared to k-selected species. Butterflies are a good example because they produce a high number of eggs but minimal survive.
What is a k-selected species?
K-selected species don’t produce many offspring but all of them have high survival rates to reach adulthood. These species have much higher lifespans than r-selected species. Bees would be more k-selected than butterflies because a larger percentage of their offspring survive.
What is allelopathy?
Allelopathy occurs when organisms use chemicals to interfere with competitors. This would be considered interference competition.
What is R if:
a) Population goes from 200 - 190
b) Population goes from 100 - 110
a) R = 0.95
b) R = 1.10
How do you calculate r?
Find r:
a) R = 0.95
b) R = 1.10
r = lnR
a) r = -0.05
b) r = 0.1
If r = -0.05, what will the population be in 15 years after the original population is 200?
Population = (initial population)(e^rt)
P = 200e^(-0.05)(15)
P = population of 94
How do you calculate doubling time? What is doubling time if r = -0.05?
Doubling time: ln2/r • 100
ln2/-0.05 • 100 = -1386.3.9 years
How do you find lx in a life table?
Divide the number of organisms in current age by number of organisms at age 0.
How do you find px in a life table?
Divide lx in the next age by lx in the current age of the table. Last slot in table does not have a px.
How do you calculate Ro?
The summation of (lxmx)
What does Ro mean?
The average number of offspring produced by an individual in her lifetime. 1.0 is a constant rate where the new generation replaces the old generation. Anything above 1.0, the population is increasing while anything under 1.0, the population is decreasing.
