BIOL 121 Chapter Notes - Chapter 5: Commensalism

29 views2 pages
24 Sep 2019
School
Department
Course
Professor
Compare and contrast r-selected vs. K-selected strategies for survival
There is a balance between care and number of offspring
K-selection: selection for life history traits that are that are sensitive to population density
and are favored at high densities; density-dependent selection
o Operates in populations living at a density near the limit imposed by their
resources: the carrying capacity, K
o Occurs when competition between individuals is stronger
r-selection: selection for traits that maximize reproductive success in uncrowded
environments (low densities); density-independent selection
o Maximizes r, the per capita rate of increase
o Occurs in environments in which population densities are well below carrying
capacity and individuals face little competition
Interpret graphs on predator-prey cycles
The relative abundance of predators and prey can also impact population sizes and cause
predator-prey Cycles, causing each population to rise and fall cyclically over time
o This pattern is an example of sinusoidal growth
If the population of prey increases, the population of predators can increase
when the population of predators increase, the population prey again decreases
as the population of prey decreases the population of predators decrease, allowing the
prey population to recover (increase)
Compare and contrast mutualism, commensalism and parasitism with the use of examples
Symbiosis: when individuals of two or more species live in direct and intimate contact with one another.
This relationship may be harmful, helpful, or neutral for each organism.
Parasitism (+/-): a symbiotic relationship in which one organism, the parasite, benefits at the expense of
another, the host, by living either within (endoparasites) or on the surface of (ectoparasites) the host.
For example, a tick on a dog or a tapeworm in a human intestine
Parasites can significantly alter the survival, reproduction, and density of their host
population, either directly or indirectly
Mutualism (+/+): a symbiotic relationship in which both participants benefit.
Unlock document

This preview shows half of the first page of the document.
Unlock all 2 pages and 3 million more documents.

Already have an account? Log in
terubarenuka and 39551 others unlocked
BIOL 121 Full Course Notes
44
BIOL 121 Full Course Notes
Verified Note
44 documents

Get access

Grade+20% off
$8 USD/m$10 USD/m
Billed $96 USD annually
Grade+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
40 Verified Answers
Class+
$8 USD/m
Billed $96 USD annually
Class+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
30 Verified Answers

Related Documents

Related Questions