APES - Unit 3 Populations
Which of the following are characteristics of generalists?
- Adaptable to many environments - Broad niche - Have an advantage when conditions change - Less likely to become extinct
Which of the following are characteristics of specialists?
- Advantaged in environments that remain constant - Narrow niche - More likely to become extinct
Pythons (FL)
- Brought to Florida as pets, released into wild by owners - Decimated mammal populations in everglades - Aggressive hunters with no natural predators
Stage 1: Pre-industrial
- High IMR and death rate due to lack of access to clean water, stable food supply, and healthcare - High TFR due to lack of access to education for women and contraceptives/family planning - Need for child agricultural labor - Little to no growth due to high CBR and CDR balancing out - Virtually no country is in stage 1 today
Struggles with R-selected
- High biotic potential (reproduction rate) = more rapid population recovery after disturbance - Low parental care means death of parent doesn't impact offspring - Not as impacted by invasive species since their population grow quickly (more likely to BE the invasive) - Larger population and faster generation time + higher change of adaptation and lower chance of extinction
Stage 4: Highly Developed
- Highly modernized countries that are very affluent - TFR declines even further as families become more wealthy and spend even more time on educational and career pursuits - Increased wealth and education brings even more prevalent use of family planning - CBR drops lower than CDR and growth rate becomes negative (population decline)
Type II
- In between R & K-selected - Smaller organisms that are less capable of protecting their young from predators/have young sensitive to disease or temperature - Ex: Birds and rodents
Cane Toad
- Introduced to eat Cane Beetles, causing sugarcane crop loss in Australia - Became invasive due to huge appetite - Drove declines in others amphibians and small reptiles
What are the three age cohorts that make up a population (give the name of the cohort and the ages that the cohort includes)
- Larger 0-14 cohort - Roughly equal 0-14 & 15-44 - Larger 15-44
Control/Removal Methods
- Legislation to prevent transport of invasives - Introduction of natural predators (biological control) - careful boat cleaning and inspection - Physical removal
Struggles with K-selected
- Low biotic potential (reproductive rate) = difficult for population to recover after a disturbance (environmental change) - High parental care means death of parent = death of offspring - Invasives (usually) outcompete for resources with high biotic potential and rapid population growth - Less likely to adapt and more likely to go extinct
Stage 2: Industrializing/Developing
- Modernizations bring access to clean water, healthcare, and stable food supply - IMR and CDR decline TFR remains high due to lack of education for women and contraceptives/family planning - Need for child agricultural labor - Generational lag (takes time for educational and social change to spread) - Rapid growth - Most countries today are in stage 2
Stage 3: Industrialized/Developed
- Modernized economy and society increase family income, so TFR declines significantly (more education for women, delayed age of marriage and childbirth in order to focus on education/career goals) - Access to contraceptives/family planning - Slowing growth rate as CBR drops closer to CDR
Type I
- Mostly K-selected - High survivorship early in life due to high parental care - High survivorship in midlife due to large size and defensive behavior - Rapid decrease in survivorship in late life as old age sets in - Ex: mammals
Type III
- Mostly R-selected - High mortality (low survivorship) early in life do to little or no parental care - Few make it to midlife; slow, steady decline in survivorship in midlife - Even fewer make it to adulthood. slow decline in survivorship in old age - Ex: insects, fish, plants
Kudzu Vine
- Planted to limit soil erosion in southern US - Grows very rapidly - Outcompetes natives for sunlight; growing over them - No herbivore control in the US
Zebra Mussel
- Transported by ship ballast water - Aggressive filter feeders eating algae many other species rely on - 1 million eggs/year
Emerald Ash Borer
-Spread by wood packing materials of ships/planes and fire wood - Larvae laid in bark, eat their way into phloem - Disrupts tree nutrient transport, killing them - Expanding range due to global warming
Factors that affect the total fertility rate of a human population
1) Cultural traditions 2) Government policies and economic incentives 3) Education level and economic opportunities for females
The TFR for replacement level fertility in developed countries is
2.1
What is the doubling time for a country with a growth rate of 3.83 %?
70/3.83 = 18.3 years
TFR (total fertility rate)
Average number of children a women in a population will have in her lifetime
r
Biotic potential; maximum potential for growth with unlimited resources
Density-dependent limiting factors
Factors that influence population growth based on size. Ex: Food, competition for habitat, water, light, even disease
Density-independent limiting factors
Factors that influence population growth independent of their size. Ex: Natural Disasters
Cohort
Group of same-age individuals
A country has a CDR of 9 and a CBR of 18. What is the growth rate and the doubling time?
Growth rate: 0.9% Doubling time: 77.8 years
Distribution
How individuals in populations are spaced out compared to each other. - Random (trees) - Uniform (territorial animals) - Clumped (herd)
Technological Advancement
Humans can alter earth's carrying capacity with tech innovation
What does IUCN stand for?
International Union for Conservation of Nature: Recognized by every nation, keeps a list of where species are and ranks them from most to least threatened
Wolves invest time and energy into the care of relatively few offspring. Identify the reproductive strategy of wolves.
K-selected
Survivorship Curve
Line that shows survival rate if a cohort in a population from birth to death
biotic potential
Maximum potential growth rate, with no limiting resources (May occur initially, but limiting resources slow growth, and eventually limit population to carrying capacity (K))
Density
Number for individuals/area (High density=higher competition, possibility for disease outbreak, possibility of depleting food source)
The tropical rain forests are known to have a large variety of animals. One example is the orchid mantis that is highly camouflaged when standing on a certain species of orchid found in tropical environments. Another species, the tropical cockroach, can live anywhere in the rain forest where it can find water and a food source. Which of the following statements best describes why it is predicted that the orchid mantis will be more affected by global climate change than the tropical cockroach will be?
Orchid mantises tend to be advantaged in habitats that remain constant; the rain forest habitat is likely to shift because of global climate change.
Woodland voles are known to have many offspring per litter that quickly reach reproductive age. Identify the reproductive strategy of woodland voles.
R-selected
Raccoons eat a variety of foods and can live in a variety of habitats, including locations near humans. Tiger salamanders eat an abundance of worms and insects and require wetland habitats so they do not dry out
Raccoons are generalists, and salamanders are specialists
Raccoons eat a variety of foods and can live in a variety of habitats, including locations near humans. Tiger salamanders eat an abundance of worms and insects and require wetland habitats so they do not dry out. Which of the following best identifies the two different species?
Raccoons are generalists, and salamanders are specialists.
Sex Ratio
Ratio of males to females closer to 50:50, the more ideal for breeding. (Die-off or bottleneck effect can lead to skewed sex ratio, limiting population growth)
Die-off/die-back
Sharp decrease in population size when resource depletion (overshoot) leads to many individuals dying
In a certain country, the birth rate is high, the death rate is high, and there are many children that are part of the workforce. The country is most likely in which of the following stages of the demographic transition?
Stage 1
What discovery supported the exponential increase in food supply?
Synthetic fixation of Nitrogen
Which of the following best describes the change in the carrying capacity of the human population if growth is limited by conditions set forth by the Malthusian theory?
The carrying capacity will decrease, and the human population size will experience a dieback
Net Migration Rate (NMR)
The difference between immigration and emigration in a given year per 1000 people in a country
Overshoot
The extent to which a population exceeds the carrying capacity of its environment
Industrialization
The process of economic and social transition from an agrarian (farming) economy to an industrial one (manufacturing based)
Malthusian Theory
The theory that population grows faster than food supply. Earth has a human carrying capacity, probably based on food production
Replacement level fertility
The total fertility rate required to offset the average number of deaths in a population in order to maintain the current population rate
Brown marmorated stink bugs are native to China and Japan. They were identified in Pennsylvania for the first time in 1998 and have since spread across North America, feeding on agricultural crops. Which of the following characteristics of the brown marmorated stink bug has led to them being an invasive species in North America?
They are tolerant of a wide range of environmental conditions
Which of the following is generally true of K-strategist species as compared to r-strategist species?
They have longer life spans.
The graph presents three survivorship curves. Choose the description that best fits the graph.
Type II could represent a coral species that has a constant decline in survivorship throughout its life.
Total Fertility Rate (TFR)
an estimate of the average number of children that each woman in a population will bear throughout her childbearing years
K
carrying capacity (when resources are limited)
Narrowest at base
declining population
The K-selection reproductive strategy maximizes survival of offspring by producing
few offspring with high levels of parental care
The CITES treaty has been helpful in protecting endangered animals and plants by
listing those species and products whose international trade is controlled
The R-selection reproductive strategy maximizes survival of offspring by producing
many offspring with low levels of parental care
Which of the following species is most likely to be an invasive species if introduced into a FAVORABLE new habitat based on the number of fertilized eggs produced each year?
oysters-5,000,000,000
The number of individuals of a single species per unit area is known as
population density
Invasive species tend to be
r-selected & generalists
Extreme pyramid shape
rapid growth
consequence of overshoot
resource depletion
Less extreme pyramid
slow, stable growth
House
stable, little to no growth
Replacement Level Fertility
the TFR required to offset the average number of deaths in a population so that the current population size remains stable
Population biologists are concerned about introduced species such as the zebra mussel in North America because
the introduced species compete for resources more effectively than native species
Crude Birth Rate (CBR)
the number of births per 1,000 individuals per year
IMR (infant mortality rate)
the number of deaths of children under the age of 1 per 1,000 births
Infant Mortality Rate (IMR)
the number of deaths of children under the age of 1 per 1,000 live births
Crude Death Rate (CDR)
the number of deaths per 1,000 individuals per year
demographic transition
the theory that as a country moves from a subsistence economy to industrialization and increased affluence it undergoes a predictable shift in population growth
Size (N)
total number of individuals in a given area at a given time