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Chapter 40: Population Ecology & the Distribution of Organisms Part 2

Biology40 CardsCreated 3 months ago

This deck covers key concepts from Chapter 40 on population ecology and the distribution of organisms, including factors affecting population density, types of lakes, and patterns of dispersion.

What do marine algae and photosynthetic bacteria do?

Supply much of the world's oxygen and consume large amounts of atmospheric carbon dioxide
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Key Terms

Term
Definition
What do marine algae and photosynthetic bacteria do?
Supply much of the world's oxygen and consume large amounts of atmospheric carbon dioxide
What is an oligotrophic lake?
A lake that is nutrient poor and oxygen rich (sterile)
What is an eutrophic lake?
A lake that is nutrient rich and often depleted of oxygen when heterotrophs use up oxygen at the end of summer
What is a wetland?
A habitat that is inundated by water at least some of the time supports plants that are adapted to water saturated soil
What is an estuary?
A transitional area between river and sea. Water in this area is often described as brackish because it is a mixture of fresh and salt water
What is an intertidal zone?
An area that is periodically submerged and exposed by the tides

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TermDefinition
What do marine algae and photosynthetic bacteria do?
Supply much of the world's oxygen and consume large amounts of atmospheric carbon dioxide
What is an oligotrophic lake?
A lake that is nutrient poor and oxygen rich (sterile)
What is an eutrophic lake?
A lake that is nutrient rich and often depleted of oxygen when heterotrophs use up oxygen at the end of summer
What is a wetland?
A habitat that is inundated by water at least some of the time supports plants that are adapted to water saturated soil
What is an estuary?
A transitional area between river and sea. Water in this area is often described as brackish because it is a mixture of fresh and salt water
What is an intertidal zone?
An area that is periodically submerged and exposed by the tides
What are species distribution a consequence of?
Both ecological factors and evolutionary history
What is dispersal?
The movement of individuals away from their area of origin or from centers of high population density
What are biotic factors?
Living factors in an environment
What are abiotic factors?
Non-living factors in an environment
What does population ecology explore?
How biotic and abiotic factors influence the density, distribution and size of a population
What is population density?
The number of individuals per unit area or volume
What factors increase population density?
Births and immigration
What factors decrease population density?
Deaths and emigration
What does ZPG stand for?
Zero Population Growth
When does ZPG occur?
When births equal deaths
What are patterns of dispersion?
The pattern of spacing among individuals within the boundaries of the population
What are three basic patterns of dispersion?
Clumped, uniform, and random
A male stickleback fish attacks other males that invade its nesting territory. Predict the likely pattern of dispersion for male sticklebacks?
Uniform
What is demography?
The study of the vital statistics of populations and how they change over time
What are life tables?
Age-specific survival and reproductive rates of individuals in a population. These are produced by following the fate of a cohort.
What does type I survivorship show?
Low death rate at birth and middle life and then death rate increases sharply in older age groups. Low infant mortality. Associated with high parental care
What does type II survivorship show?
Relatively constant birth and death rate.
What does type III survivorship show?
High death rates early in life, but then death rates decline for older age groups. Usually associated with many offspring and low parental care.
What is population growth rate?
The change in the number of individuals in a given area over time
What is the formula for population growth rate?
r = (births-deaths/N)
What is exponential population growth?
Described as an idealized population growth in an environment with unlimited resources.
What shape curve is exponential population growth?
J-shaped
What is intrinsic rate of increase?
The per capita rate at which an exponentially growing population increases in size at each instant in time (ideal conditions, unlimited resources)
What is carrying capacity?
The maximum population size that a particular environment can sustain (K)
What is logistical population growth?
It charts the growth of a population with unlimited resources when the population is low (exponential growth), but then the rate of population growth approaches zero as the population size nears the carrying capacity
What is true about the birth and death rate during exponential growth?
Birth rate is much greater than death rate
What is true about the birth and death rate as the population approaches the carrying capacity?
Birth rate begins to decrease and/or death rate increases
What is true about the birth and death rate at the carrying capacity?
Rates are roughly equal
What makes up an organism's life history?
Due to limited resources, there must be a tradeoff between survival and reproductive traits (frequency, number of offspring, and parental care), which make up an organisms' life history
What is k-selection?
Selection of life history traits that are sensitive to population density and carrying capacity
What is r-selection?
Selection of life history traits that maximize reproductive success in uncrowded environments
What happens at large population sizes?
Negative feedback is provided by density-dependent regulation which halts population growth through mechanisms that reduce birth rates or increase death rates
What are the 6 density-dependent mechanisms?
Competition for resources, predation, disease, toxic wastes, territoriality, intrinsic factors
What are density-independent mechanisms?
Factors that are unrelated to population density. These factors will affect the same % of a population regardless of population density.