APES Unit 3 Notes - Specialist vs. Generalist, K-selected vs. r-selected, Survivorship Curves

3.1 Specialist vs. Generalist Species Specialists: Smaller range of tolerance, or narrower ecological niche makes them more prone to extinction - Specific food requirements (bamboo) - Less ability to adapt to new conditions Generalists: Larger range of tolerance, broader niche mak...

3.1 Specialist vs. Generalist Species Specialists: Smaller range of tolerance, or narrower ecological niche makes them more prone to extinction - Specific food requirements (bamboo) - Less ability to adapt to new conditions Generalists: Larger range of tolerance, broader niche makes them less prone to extinction & more likely to be invasive - Broad food req. - High adaptability GENERALISTS VS. SPECIALISTS “ Identify ONE characteristic of specialist species and explain how that characteristic makes them more likely to become extinct than generalist species. 5 3.2 K-selected & r-selected species Objectives, EKs, and Skills  r-selected - “quantity” Quality vs. Quantity ▰ Many offspring, little to no parental care K-selected - “quality” ▰ May reproduce only once, but generally reproduce many times throughout ▰ Few offspring, heavy parental care lifespan to protect them ▻ Ex: insects, fish, plants ▰ Generally have fewer reproductive ▰ Shorter lifespan, quick to sexual events than r-strategists maturity = high biotic potential = high ▻ Ex: most mammals, birds population growth rate ▰ Long lifespan, long time to sexual ▻ More likely to be invasive maturity = low biotic potential = ▻ Better suited for rapidly changing slow population growth rate environmental conditions ▻ More likely to be disrupted by environmental change or invasive species  r-selected: Habitats/Populations ▰ Usually live in habitats with lower competition for resources ▰ Population are more likely to fluctuate K-selected: above and below carrying capacity ▰ Usually live in habitats with higher (overshoot and die-off) competition for resources ▻ “r” is the variable used to represent ▰ Populations that reach carrying maximum reproductive rate in capacity (K) usually remain at ecology stable size, near K ▻ Hence, r-selected or r-strategist ▻ Hence, K-selected or K-strategist Traits or characteristics of r-selected & K-selected species 10 It’s a Spectrum Spectrum of Parental Care  K-selected r-selected ▰ Low biotic potential (rep. rate) = ▰ High biotic potential (rep. rate) = more hard for pop. to recover after a rapid pop. recovery after disturbance disturbance (env. change) ▰ Low parental care means death of ▰ High parental care means death of parent doesn’t impact offspring parent = death of offspring ▰ Not as impacted by invasive species ▰ Invasives (usually r) outcompete since their pop. grow quickly for resources with high biotic ▻ More likely to be the invasive potential & rapid pop. growth ▰ Larger pop. & faster generation time = ▰ Less likely to adapt & more likely higher chance of adaptation & lower to go extinct chance of extinction Invasiveness & Disturbances 13 “ Identify ONE characteristic of an r-selected species that could increase the likelihood of the r-selected species becoming a more successful invasive species than K-selected species 14 Describe the relationship between Zebra Mussel and Unionid Mussel population density in the Hudson River 15 “ #ThinkLikeAMountain #WriteLikeAScholar 16 3.3 Survivorship Curves Objectives, EKs, and Skills  ★ Faster drop in line = quicker die-off of individuals ★ Slower drop in line = longer avg. lifespan Survivorship Curve: line that shows survival rate of a cohort (group of same-aged individuals) in a pop. from birth to death Type I, II, and III Survivorship Type I (mostly K-selected) Type III (mostly r-selected) ▰ High survivorship early in life due ▰ High mortality (low survivorship) early to high parental care in life due to little to no parental care ▰ High survivorship in mid life due to ▰ Few make it to midlife; slow, steady large size & defensive behavior decline in survivorship in mid life ▰ Rapid decrease in survivorship in ▰ Even fewer make it to adulthood; slow late life as old age sets in decline in survivorship in old age ▻ Ex: most mammals ▰ Ex: insects, fish, plants Type II (in between r & K) ▰ Steadily decreasing survivorship throughout life FRQ Practice 3.3 Describe the trend in survivorship shown in this graph. Justify which type of survivorship curve these data represent. “ #ThinkLikeAMountain #WriteLikeAScholar 22 3.4 Carrying Capacity Objectives, EKs, and Skills  ★ Fig. 1 is theoretical ★ Fig. 2 is more realistic ★ Pop. briefly “overshoots” (K) and then die-off happens Fig. 1 Fig. 2 Carrying Capacity (K): the max. Number of individuals in a pop. that an ecosystem can support (based on limiting resources) Carrying Capacity (K) ▰ Highest pop. size an ecosystem can ▰ Die-off: sharp decrease in pop. size support based on limiting resources: when resource depletion (overshoot) ▻ Food leads to many individuals dying ▻ Water ▻ Ex: many deer starve with too ▻ Habitat (nesting sites, space) many new fawns feeding in ▰ Overshoot: when a population briefly spring exceeds carrying capacity ▻ Ex: deer breed in fall, give birth all at once in spring; sudden spike in pop. = overshoot ▰ Consequence of overshoot: resource depletion ex: overgrazing in deer Die-off Example ▰ Reindeer of St. Paul Island ▻ 25 introduced in 1910 ▻ Growth was gradual (10’-30’), then exponential (30’-37’) ▻ Carrying capacity was overshot ▻ Sharp die-off lead to pop. crash as food resource (lichen) were severely depleted ▰ Real pops. don’t always fluctuate around carrying capacity. If resource depletion is severe enough, total pop. crash can occur Predator-Prey 1. Hare pop. increase due to low predator pop. (lynx) 2. Lynx pop. increase due to increase in food (hare) 3. Increasing lynx pop. limits hare pop; leads to die-off 4. Hare die-off decreases lynx food source, leading to die-off 5. Hare pop. increase due to low predator pop. (lynx) FRQ Practice 3.4 Explain the impact that the canine virus had on the moose population based on the graph. “ #ThinkLikeAMountain #WriteLikeAScholar 3.5 Pop. Growth & Resource Availability Objectives, EKs, and Skills  Pop. Characteristics ▰ Size (N): total # of individuals in a given area at a given time ▻ Larger = safer from population decline ▰ Density: # of individuals/area ▻ Ex: (12 panthers/km2) ▻ High density = higher competition, possibility for disease outbreak, possibility of depleting food source ▰ Distribution: how individuals in population are spaced out compared to each other ▻ Random (trees) ▻ Uniform (territorial animals) ▻ Clumped (herd/group animals)  Pop. Characteristics & Growth Factors ▰ Sex Ratio: ratio of males to females. ▰ Density-Independent Factors: Closer to 50:50, the more ideal for breeding factors that influence population (usually) growth independent of their size ▻ Die-off or bottleneck effect can lead to skewed sex ratio (not enough ▻ Ex: natural disasters (flood, females) limiting pop. growth hurricane, tornado, fire) ▻ It doesn’t matter how big or ▰ Density-Dependent Factors: factors that small a pop. is, natural influence population growth based on size: disasters limit them both ▻ Ex: food, competition for habitat, water, light, even disease ▻ All of these things limit pop. growth based on their size; aka - small pop. don’t experience these, large do Ex. of Density-Dependent Factor ▰ Food is a density dependent factor. (also a limiting resource) ▻ When twice as much food was added to the dish, both species increased carrying capacity by about 2x  Biotic potential = exponential growth Logistic growth = initial rapid growth, then limiting factors limit pop. to K ▰ Biotic Potential = maximum potential growth rate, with no limiting resources - also called intrinsic rate of increase (r) ▻ May occur initially, but limiting resources (competition, food, disease, predators) slow growth, & eventually limit pop. to carrying capacity (K)  Calculating Population Change ▰ Population Size = (Immigrations + births) - (immigrations + deaths) ▻ Ex: An elk pop. of 52 elk has 19 births and 6 deaths in a season, and 5 new elk immigrate to the herd and 0 elk emigrate from the herd (19+5) - (6+0) = +18 elk 52 + 18 = 70 elk 37  FRQ Practice 3.5 Calculate the percent change in the population size of a 14 wolf pack that experiences 5 deaths, 3 births, and 4 new wolves released into the pack from a nearby wildlife sanctuary. “ #ThinkLikeAMountain #WriteLikeAScholar 3.6 Age Structure Diagrams Objectives, EKs, and Skills Age Cohorts Age cohorts & growth = groups of similarly aged individuals 0-14 = prereproductive; 15 - 44 = reproductive age; 45 + = post reproductive Size difference between 0-14 & 15-44 indicates growth rate ○ Larger 0-14 cohort = current & future growth ○ Roughly equal 0-14 & 15-44 = slight growth/stable ○ Larger 15-44 = pop. decline - Extreme Pyramid shape = rapid growth - Less extreme pyramid = slow, stable growth - House = stable, little to no growth - Narrowest @ base = declining pop. - Practice Reading Diagrams Highest to Lowest Growth Rate India > US > China > Germany Number of 0-14 Individuals - India = 360 million - US = 62 million - Germany = 11.5 million - China = 270 million  FRQ Practice 3.6 Identify the country with the slowest pop. growth rate and explain your answer “ #ThinkLikeAMountain #WriteLikeAScholar 3.7 Total Fertility Rate (TFR) Objectives, EKs, and Skills  TFR & Infant Mortality ▰ Total Fertility Rate (TFR): avg. number ▰ Infant Mortality Rate (IMR): of children a woman in a population will number of deaths of children under bear throughout her lifetime 1 year per 1,000 people in a pop. ▻ Higher TFR = higher birth rate, ▻ Higher in less developed higher pop. growth rate (generally) countries due to lack of access to: health care, clean water, ▰ Replacement Level Fertility: the TFR enough food required to offset deaths in a pop. and ▰ Higher IMR = higher TFR, due to keep pop. size stable families having replacement ▻ About 2.1 in developed countries children (replace mom & dad) ▻ Higher than 2.1 in less developed countries due to higher infant mortality Global TFR Infant Mortality  Infant Mortality & TFR Factors in IMR Decline - Access to clean water - More reliable food supply - Access to healthcare (hospitals, vaccines, vitamins & supplements for moms & babies)  Factors That Affect TFR ▰ Development (Affluence): more ▰ Gov. Policy: can play a huge role in developed, or wealthy nations have a fertility by coercive (forceful) or lower TFR than less developed nations noncoercive (encouraging) policies ▻ More educational access for women ▻ Forced or vol. sterilization ▻ China’s 1 (now 2) child policy ▻ More econ. opportunity for women ▻ Tax incentives to have fewer children ▻ Higher access to family planning ▻ Microcredits or loans to women without education & contraceptives children to start businesses ▻ Later age of first pregnancy ▻ Less need for children to provide income through agricultural labor Affluence & TFR ▰ More access to contraceptives & family planning ▰ Ed./econ. opportunities require time, leaving less for raising children ▰ Lower IMR = lower TFR Female Education & TFR ▰ More education = fewer unplanned pregnancies ▰ More education = more job. opportunities for women ▻ Alternative to marrying young FRQ Practice 3.7 Identify and discuss TWO of the causes for the trend in worldwide TFR. “ #ThinkLikeAMountain #WriteLikeAScholar 3.8 - Human Population Dynamics Thomas Malthus Objectives, EKs, and Skills Does Earth Have a Human Carrying Capacity? Malthusian theory (what Malthus theorized): - Earth has a human carrying capacity, probably based on food production - Human population growth is happening faster than growth of food production - Humans will reach a carrying capacity limited by food Technological Advancement - Humans can alter earth’s carrying capacity with tech. Innovation - Ex: synthetic fixation of Nitrogen in 1918 leads to synthetic fertilizer, dramatically increasing food supply Exponential Increase in Food Supply 60  Birth Rate, Death Rate, and Growth ▰ Growth Rate (r) = % increase in a population (usually per year) ▻ Ex: a growth rate of 5% for a population of 100 means they grow to 105 ▰ Crude Birth Rate & Crude Death Rate (CBR & CDR) ▻ Births & deaths per 1,000 people in a population ▻ Ex: Global CBR = 20 & CDR = 8 ▻ Calculating Growth Rate (r) Divide by 10 because CDR & CDR are per 1,000 and growth rate is % or per 100 Growth rate always expressed as %  Doubling Time (Rule of 70) ▰ Rule of 70: The time it takes (in years) for a population to double is equal to 70 divided by the growth rate Ex: Global growth rate = 1.2% 70/1.2 = 58.3 years Global pop. will double in 58.3 years  Calculating Population Change ▰ Practice Problem: A country has a CDR of 9 and a CBR of 18. ▻ Calculate the annual growth rate, and the doubling time ▰ Solution: (18-9)/10 = 9/10 = 0.9% growth rate 70/0.9% = 77.77 years to double  Factors Affecting Human Pop. Growth ▰ Factors that increase pop. growth ▰ Factors that decrease population ▻ Higher TFR → higher birth rate growth rate ▻ High death rate ▻ High infant mortality rate can drive up TFR (replacement children) ▻ High infant mortality rate ▻ Increased development ▻ High immigration level (education & affluence) ▻ Increased access to clean water & ▻ Increased education for women healthcare (decrease death rate) ▻ Delayed age of first child ▻ Postponement of marriage age  Standard of Living Indicators ▰ Standard of Living ▰ Life expectancy = key health ▻ What the quality of life is like for indicator of standard of living people of a country based ▻ Average age a person will ▰ Gross Domestic Product (GDP) = key live to in a given country economic indicator of standard of living ▻ Increases with access to ▻ Total value of the goods & clean water, health care, services produced stable food sources ▻ Per capita GDP is total GDP/total population High GDP & life expectancy are both indicators of development & low pop. growth  FRQ Practice 3.8 Describe one human activity related to a rapidly growing human population that is having an impact on biodiversity. Propose a solution a government could take to slow population growth. 3.9 Demographic Transition Objectives, EKs, and Skills  Industrialization ▰ Industrialization: the process of ▰ Industrializing/developing economic and social transition from an ▻ part way through this transition agrarian (farming) economy to an ▻ Decreasing death rate & IMR industrial one (manufacturing based) ▻ Rising GDP ▰ Pre-industrialized/Less developed ▰ Industrialized/developed: completed the transition ▻ A country that has not yet made the ▻ Very low CDR & IMR agrarian to industrial transition ▻ Very High GDP ▻ Typically very poor (low GDP) ▻ Low TFR ▻ Typically high death rate & high infant mortality ▻ High TFR for replacement children & agricultural labor Development Status  Stage 1 - Preindustrial ▰ High IMR & high death rate due to lack of access to clean water, stable food supply, and healthcare ▰ High TFR due to lack of access to: ▻ Ed. for women ▻ Contraceptives/family planning ▰ Need for child agricultural labor ▰ Little to no growth due to high CBR & CDR balancing each other out Ex: Virtually no country is in phase 1  Stage 2 - Industrializing/Developing ▰ Modernizations brings access to clean ▰ Econ./societal Indicators water, healthcare, stable food supply ▻ Low per capita GDP ▻ IMR & CDR decline ▻ Shorter life-expectancy ▰ TFR remains high due to ▻ High infant mortality ▻ Lack of ed. for women & ▻ High TFR contraceptives/family planning ▻ Low literacy rate & school life ▻ Need for child agricultural labor expectancy for girls ▻ Generational lag ( takes time for ed. & societal change to spread ▰ Rapid growth, due to high CBR and declining CDR  Stage 3 - Developed/Industrialized ▰ Modernized economy and society ▰ Econ./societal Indicators increase family income, so TFR declines ▻ High per capita GDP significantly due to ▻ Long life-expectancy ▻ More ed. opportunities for women ▻ Low infant mortality ▻ Delayed age of marriage & first child ▻ TFR near replacement level to focus on ed./career (2.1) ▻ Access to family planning & ▻ High literacy rate & school life contraceptives expectancy for all ▰ Slowing growth rate as CBR drops closer to CDR  Stage 4 - Post-Industrialized/Highly Developed ▰ Econ./Societal Indicators ▰ Highly modernized countries that are ▻ Very high per capita GDP very affluent ▻ Longest life-expectancy ▻ TFR declines even further as ▻ TFR below replacement level families become more wealthy and (2.1) spend even more time on educational & career pursuits ▻ Highest contraceptive use rates ▻ Increased wealth & education brings even more prevalent use of family planning & contraception ▰ CBR drops lower that CDR & growth becomes negative (pop. decline) Stages & Development ▰ 1 = pre-industrial ▰ 2 = developing ▰ 3= Developed ▰ 4 = Highly developed 75  FRQ Practice 3.9 Identify the stage of this graph in which population grows the fastest and explain why this is the case. Besides population growth rate, describe one economic or societal indicator of a country in this phase.