Chapter 19 Flashcards
Define a life table and what it is used for
Provide important info about the life history of an organism and the life expectancy of indivduals at each age
What does a survivorship curve show? What are the three different types and how are they different? Humans and other mammals exhibit which type of curve?
Survivorship: a graph of the number of individuals surviving at each age interval versus time.
Type I: mortality is low in the early and middle years and occurs mostly in older individuals, type II: mortality is relatively constant throughout the entire lifespan, and mortality is equally ikely to occur at any point in the lifespan , type III: early ages experience the highest mortality with much lower mortality rates for organisms that make it to advanced years.
Humans and most mammals exhibit a type I survivorship curve.
Define logistic, and exponential growth and provide examples of each.
Logistic growth model yields and S-shaped curve & is a more realistic model of population growth than exponential growth. Ex. sheep & harbor seals
Exponential growth describes theoretical populations that increase in numbers without any limits to their growth. Ex. bacteria growing in a flask
What is the difference between r-selected and K-selected species. Examples
K-selected species are adapted to stable, predictable environments. Tend to have fewer but larger offspring whereas r-selected species are adapted to unstable and unpredictable environments. Tend to have large numbers of small offspring.
What are density-dependent and density-independent regulations? Examples
Density-dependent regulation includes factors in which the density of the population affects growth rate and mortality. Factors tend to be bilogical in nature Ex. predation and parasites.
Density-independent regulation factors tend to be physical in nature cause mortality of a population regardless of its density. Ex. weather, natural disasters, and pollution.
Define commensalism, parasitism, and mutualism
Commensalism: a relationship occurs when one species benefits from a close prolonged interaction, while the other is neither benefited nor harmed.
Parasitism: parasite benefits but the host is harmed.
Mutualism: symbiotic relationship where both species benefit from their interaction.
What are some examples of Behavioral, Mechanicalm, and Chemical defenses?
Mechanical: presence of armor in animals or thorns in plants
Chemical: toxic secondary plant compunds
Behavioral: body shape and coloration
What is mimicry?
Defense mechanism in which some prey species have evolved into mimic the coloration of other harmful/poisonous prey species to avoid being eaten
Define an invasive species
Non-native organisms that when introduced to an area out of its native range, alter the community they invade
Define species distribution pattern
The distribution of individuals within a habitat at a particular point of time
