Differentiate between density-dependent and density-independent factors affecting population growth. Provide two
examples for each, along with a brief explanation. What will be an ideal response?
Concepts to Consider: Density-dependent factors are those whose influence on the growth
of a population reflects the population density. As the population density increases, the
impact of these factors increases and contributes to a slowing of the growth rate through an
increase in the death rate or a decrease in the birth rate. The converse is also true. Examples
of density-dependent factors include predation, disease, and competition. Densityindependent
factors tend to be abiotic, are not influenced by population density, and may
have unpredictable effects on the population. Examples of density-independent factors
include unusual weather events such as early freezes, floods, fires, and hurricanes.
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You are relieved to see that the patient received a tetanus vaccine at her last checkup. The vaccine ____________. A. exposed the patient to C. tetani so that she contracted a mild version of tetanus. B. exposed the patient to deactivated C. tetani, so that her B cells would produce antibodies to the bacteria with minimal risk of contracting the disease. C. stimulated the production of mast cells by her bone marrow. D. exposed the patient to other types of bacteria, so that her immune system would be prepared for infection by prokaryotes.
When you look at a phylogenetic tree of reptile classes, turtles, lizards and snake, and crocodiles are grouped together and birds are set off to the side but with a common ancestor for both groups. This would
A. be a monophyletic tree. B. be a paraphyletic tree. C. be a polyphyletic tree. D. have the taxonomy wrong because birds should be included with the others to make it a monophyletic tree. E. be a paraphyletic tree but the taxonomy wrong, because birds should be included with the others to make it a monophyletic tree.
________ is a polymer of glucose.
A. Triglyceride B. Cellulose C. DNA D. Protein E. RNA
Red blood cells originate from the bone marrow.
a. true b. false