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45 Cards in this Set
- Front
- Back
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a feature common to all populations of living organisms
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GROWTH
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number of individuals per unit area or volume
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population density
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a plot of the number of members of a cohort that are still alive at each age; one way to represent age-specific mortality
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survivorship curve
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growth of a population in an ideal, unlimited environment, represented by a J-shaped curve when population size is plotted over time
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exponential population growth
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population growth that levels off as population size approaches carrying capacity
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logistic population growth
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referring to any characteristic that varies with population density
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density dependent factor
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any characteristic not affected by population density
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density-independent factor
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the relative number of individuals of each age in a population
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age structure
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the study of changes over time in the vital statistics of populations, especially birth rates and death rates
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demography
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human population growth has ___ in the last century?
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accelerated
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individuals of a given species that occur together at one place and time
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population
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formula for population change
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growth rate = births-deaths
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rapid, requires ideal conditions
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exponential growth
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the number of individuals an environment can support
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carrying capacity
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grow larger
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positive growth
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grow smaller
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negative growth
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populations remain the same size
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zero growth
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two types of positive growth
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exponential or logistic
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growth in which the time required to double the size of the population becomes shorter and shorter
-what kind of curve? |
exponential
-J |
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represents the carrying capacity
-what kind of curve |
logistical growth
-s curve |
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limiting factors of growth
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food, minerals, water, space, carrying capacity
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what contributes to the growth of a population?
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mortality and survivorship
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-depends on the ages of the organisms in it?
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population growth rate
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death rate
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mortality
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proportion of an original population that survives to a certain age
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survivorship
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shapes vary with type of population, number of young, sexual or asexual reproduction, level of care for young
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survival curves
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-juvenile survival is high and most mortality occurs among older individuals
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type 1 survivorship (humans, large mammals)
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-individuals in a population die at equal rates, regardless of age
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type 2 survivorship (Beldings ground squirrels, rodents, invertebrates, lizards, some annual plants)
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--die at a high rate as juveniles and then at much lower rates later in life
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type 3 survivorship (long lived plants, many fishes, most marine invertebrates)
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-new individuals going the population from other populations
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immigration
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individuals leaving the population
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emigration
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examples of density independent limiting factors
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soil, nutrients, weather, physical features
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density dependent limiting factors examples
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-competition for resources, accumulation of poisonous wastes
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type of diagram of age structure
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bar graph
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shows current composition of population by age and gender, can be used to predict future size based on number of females and birth rate
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age structure diagram
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countries with rapid growth, what shape is the age structure diagram?
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kenya, nigeria, saudi arabia
-cone |
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slow growth countries
-shape of age structure diagram |
united states, canada
-less prominent cone |
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zero growth countries
shape |
denmark, italy
-bullet |
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negative growth countries
-shape |
germany, hungary
-thumb |
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reasons of exponential increase in human population in 19th century
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-industrial revolution, better nutrition, advances in medicine, lowered death rate, increased birth rate
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increased carrying capacity
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human technology
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*** current increases in population are higher in developing countries ****
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k
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prediction of the human pop by 2050?
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7.3 to 10.7 billion peeps
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the max number of individuals in a population that can be sustained in an environment
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carrying capacity
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competition for resources, disease, predation
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density dependent limiting factors
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