Make a connection between Easter and the movie “Night at the Museum” with chapter 8 (populations)

Do you know where it is?

Easter Island *Formed from volcanic eruptions *64 sq miles *2300 miles west of Chile

Easter Island Story First inhabitants – 700 AD 7000-9000 people around 1500’s 1722, Europeans landed – 2500 people What happened?

End of Easter Island – YouTube

APES Chapter 8

http://www.youtube.com/watch?v=gS-jZp_cvqY

REINDEER ON ST. MATTHEW ISLAND

Key Concepts Environmental factors affecting populations Role of predators in controlling populations Reproductive patterns and species survival Conservation biology Human impacts on populations Lessons about sustainable living

Oh Deer!

http://www.shodor.org/interactivate/activities/

Sea Otters: Back from the Brink of Extinction? Keystone species Pollution effects Importance of otters Orcas Fig. 8-1, p. 160

Populations A. Characteristics of a population (1) size (number of indiv.) (2) density (spatial) (3) dispersion (spatial pattern) (4) age distribution

Population B. Measuring population size, density, distribution, etc. APES Chapter 8 Population B. Measuring population size, density, distribution, etc. 1. Count vs. Sampling 2. Sampling Quadrats Transects Line Belt Mark-recapture Quadrat - sample units or plots that vary in size, shape, number and arrangements, depending on the nature of the vegetation, site conditions and purpose of study. Transects – line transect – presence or absence of species; continuous (every plant that touches the tape) or interrupted (every meter, every 10 meters, etc.) belt transect – presence or absence, and abundance (% cover)  relative abundance http://www.countrysideinfo.co.uk/what_method.htm

Quadrats - % Cover and # Random Along transect

Line Transect – Presence/Absence

Belt Transect Presence/Absence and Abundance Number of individuals Distance (m)

Mark-Recapture re ^

Chapter 8 Part 2

C. Dispersion Patterns of Organisms APES Chapter 8 C. Dispersion Patterns of Organisms Clumped or aggregated – common Even – rare in nature, creosote bush is an example Random Fig. 8-2 p. 161

Creosote bush – even dispersion

Penguins – Even or Uniform Distribution

D. Population Dynamics Changes in the characteristics of a population, occur in response to (1) environmental stress (2) changes in environmental conditions

1. Exponential Growth 2. Logistic Population Growth APES Chapter 8 1. Exponential Growth 2. Logistic Population Growth Right graph – logistic growth, S curve, levels off when meets carrying capacity (K) Fig. 8-4, p. 163

ZPG = Zero population growth APES Chapter 8 Population Dynamics Carrying capacity - maximum population of a particular species that a given habitat can support over a given period of time. Biotic potential (intrinsic rate of increase [r]) = births – deaths  Population size = births – deaths + immigration – emigration ZPG = Zero population growth Carrying capacity – maximum population of a particular species that a given habitat can support over a given period of time. Pop growth rate also called intrinsic rate of natural increase (r) = births – deaths High intrinsic growth rate – Show exponential growth, J curve Environmental resistance – all factors that limit pop growth in nature Population of a species at any given time is balance between intrinsic growth rate of species, and environmental resistance. Right graph – logistic growth, S curve, levels off when meets carrying capacity (K) Minimum viable population (MVP) – great importance to conservation biologists. Problems with small populations 1) not enough indiv to find mates, 2) genetically related indiv. May interbreed which weakens species, 3) low genetic diversity so not able to adapt in response to changing env. Conditions. Result is extinction if Intrinsic growth rate is real low.

5. Environmental resistance - all factors that limit pop growth in nature

APES Chapter 8 Population size influenced by birth rate, death rate, immigration and emigration Population growth rate = births + immigration – deaths – emigration Zero population growth (ZPG) – 0 net growth, increase = decrease Biotic potential – capacity for growth, populations vary Abiotic factors affecting population size – light (just right, too much or too little), temperature, chemicals Biotic factors – reproductive rate, generalized/specialized niche, food supply, habitat, competitors, predators, disease, parasites, ability/inability to migrate to another habitat, ability/inability to adapt to env. change Fig. 8-3, p. 162

Logistic vs Exponential Growth

Logistic Growth of Sheep Population APES Chapter 8 Logistic Growth of Sheep Population 2.0 1.5 1.0 .5 Number of sheep (millions) 1800 1825 1850 1875 1900 1925 Year Sheep on island of Tasmania between 1800 and 1925. Introduced, pop’s increased, reached carrying capacity, overshot it, stabilized and fluctuated around carrying capacity. Logistic growth – growth can overshoot carrying capacity because of a reproductive time lag – the time needed for the birth rate to fall and the death rate to rise in response to resource overcomsumption. Fig. 8-5, p. 163

When Population Size Exceeds Carrying Capacity APES Chapter 8 When Population Size Exceeds Carrying Capacity Overshoots Reproductive time lag Diebacks (crashes) overshoots – a population grows rapidly and passes the carrying capacity reproductive time lag – a lag between environmental change and change in length of gestation (or whatever changes); OR the time it takes for the birth rate to fall and the death rate to rise in response to resource over-consumption) dieback (crash) - Sharp reduction in the population of a species when its numbers exceed the carrying capacity of its habitat. See carrying capacity.

Exponential Growth, Overshoot and Population Crash of Reindeer APES Chapter 8 Exponential Growth, Overshoot and Population Crash of Reindeer 2,000 1,500 Number of reindeer 1910 1920 1930 1940 1950 Year 1,000 500 Dieback or crash – when overshoot K. Reindeer were introduced to a small island off Alaska. Overshot the carrying capacity because there were no predators so they over-grazed the environment and ran out of food. Human population of Ireland had similar crash during the potato famine due to the potato blight of 1845. About 1 million people died and 3 million emigrated to other countries. Fig. 8-6, p. 164

6. Minimum Viable Population APES Chapter 8 6. Minimum Viable Population (MVP) - the smallest possible size at which a biological population can exist without facing extinction Start here 10/27/08 6th period

E. Reproductive Patterns and Survival APES Chapter 8 E. Reproductive Patterns and Survival 1. Asexual reproduction – clones Sexual reproduction – sex cells Timing of reproduction 2. Semelparous - reproduce once and die; usually short-lived but salmon and agave 3. Iteroparous - reproduce many times; usually long-lived Asexual reproduction – when mother cell divides to produce two identical daughter cells that are clones of the mother cell. Common in single-celled organisms like bacteria and yeast, and in some insects like aphids (parthenogenic females reproduce daughter clones), and in social insects like ants and honeybees Sexual reproduction – reproduce offspring by combining sex cells or gametes from both parents, offspring have traits from both parents; increases genetic variation

Positions of r-selected and K-selected Species on Population Growth Curve Number of individuals Time Carrying capacity K species; experience K selection r species; r selection K Fig. 8-9, p. 166

4. r-Selected Species cockroach dandelion Many small offspring APES Chapter 8 r-Selected Species cockroach dandelion Many small offspring Little or no parental care and protection of offspring Early reproductive age Most offspring die before reaching reproductive age Small adults Adapted to unstable climate and environmental conditions High population growth rate (r) Population size fluctuates wildly above and below carrying capacity (K) Generalist niche Low ability to compete Early successional species Opportunists 4. r-selected species – exponential growth, High intrinsic rate of increase (r) reprod early in life, have short generation times, reproduce many times, have many usually small offspring, little or no parental care given to offspring, short-lived (usually have life-span of less than year). Reproduce often and many so it doesn’t matter if some offspring don’t survive. Tend to be opportunists – reproduce and spread rapidly in good conditions or when disturbance opens space, early successional species. Don’t last because they can’t survive changing env. conditions, or invasion by more competitive species – irregular and unstable boom-bust cycles. Fig. 8-10a, p. 167

5. K-Selected Species elephant saguaro Figure 8-10b, p. 167 APES Chapter 8 K-Selected Species 5. elephant saguaro Fewer, larger offspring High parental care and protection of offspring Later reproductive age Most offspring survive to reproductive age Larger adults Adapted to stable climate and environmental conditions Lower population growth rate (r) Population size fairly stable and usually close to carrying capacity (K) Specialist niche High ability to compete Late successional species Competitor species K-selected species – K for carrying capacity, AKA competitor species, put little energy into reproduction, reproduce later in life, few offspring, long generation times, put most of energy into nurturing and protecting young until they reach reproductive age. Young develop inside mother, are large, mature slowly. Results in a few big and strong individuals that can compete for resources. Do well in competitive situations. Show logistic growth. e.g., most large mammals (elephants, whales, humans), birds of prey, large and long-lived plants like trees. Many are prone to extinction because of long generation times and low reproductive rates. Do best in ecosystems with fairly constant environmental conditions, compared to opportunist species that thrive in habitats with disturbances. Most speices are somewhere in between r-selected and K-selected strategies Figure 8-10b, p. 167

6. Survivorship Curves Age APES Chapter 8 6. Survivorship Curves late loss or Type I (usually K–strategists), in which high mortality is late in life constant loss or Type II (such as songbirds), in which mortality is about the same for any age; early loss or Type III (usually r–strategists), in which high mortality is early in life. Late loss – high survival in young, high mortality in oldest age group only Constant loss – - death rate same no matter the age Early loss - high mortality among young Age Fig.8-11, p. 167

F. Limitations on Population Size APES Chapter 8 F. Limitations on Population Size Carrying capacity Density-dependent controls – greater effect on population as density increases. e.g. competition, predation, disease, parasitism Density-independent controls – affect population’s size regardless of density e.g. flood, hurricane, drought, fire, pesticide, habitat destruction Carrying capacity - maximum population of a particular species that a given habitat can support over a given period of time. Density-independent controls – affect population’s size regardless of density. Examples are floods, hurricanes, severe drought, fire, habitat destruction and pesticides. Density-dependent controls – greater effect on population as density increases - competition for resources, predation, parasitism, disease. Bubonic plague, 14th century Europe, at least 25 million people died.

4. The Role of Predation in Controlling Population Size APES Chapter 8 4. The Role of Predation in Controlling Population Size a. Predator-prey cycles b.Top-down control c. Bottom-up control Population size (thousands) 160 140 120 100 80 60 40 20 1845 1855 1865 1875 1885 1895 1905 1915 1925 1935 Year Hare Lynx Predator-prey cycles– poorly understood; sharp increase in numbers followed by periodic crashes. – Lynx-hare cycle – 10 year cycle. Once thought that thy regulated each other’s cycles. Now think that hare population is regulated by (1) predation by lynx and other predators (top-down control), and (2) changes in available food supply (bottom-up control). Lynx population fluctuates in response to hare population. Moose and wolf on Isle Royale, between Minnesota and Ontario – moose immigrated there across ice in early 1900’s. By 1928 they had stripped island of their preferred food. In 1940’s timber wolves immigrated across ice to island. The multiplied and killed old, sick and young moose, keeping their numbers from reaching high levels again. Starting in 1980 the wolf population has declined due to disease and low reproductive rate due to lack of genetic variability from inbreeding. Moose population rose and crashed. Then wolf population rose by eating dying mooses, so the populations’ cycling continues. Fig. 8-8, p. 165

Rabbits and Wolves Simulation Get into groups of 2 people Log into a computer Go the simulation website Answer questions on worksheet

G. Natural Population Curves APES Chapter 8 G. Natural Population Curves /chaotic 4 types of population fluctuations Stable – slight fluctuations above and below carrying capacity. Undisturbed tropical rain forests – little variation in temperature or precipitation Irruptive – occasionally explodes or irrupts to a higher peak, some factor temporarily increases carrying capacity – more food or fewer predators. House mouse, raccoon. Cyclic – occur over regular time period for poorly understood reasons. e.g. (1) lemmings – rise and fall every 3-4 years, (2) grouse, lynx, and snowshoe hare – rise and fall on 10 year cycle. Irregular/chaotic – chaotic behavior, no recurring pattern. Either due to chaos in system, or unknown underlying patterns and interactions. Fig. 8-7 p. 164

Conservation Biology: Sustaining Wildlife Populations What is conservation biology? Which species are endangered? How are ecosystems functioning? How can ecosystems be sustained? Principles of conservation biology Aldo Leopold’s ethical principles Bioinformatics

H. Conservation Biology Conservation biology is the interdisciplinary science that deals with problems of maintaining Earth's biodiversity, including genetic, species, and ecosystem components of life. conservation involves the sensible use of natural resources by humans; three underlying principles: biodiversity and ecological integrity are useful and necessary for life and should not be reduced by human activity; humans should not cause or hasten premature extinction of populations and species; the best way to preserve biodiversity and ecological integrity is to protect intact intact ecosystems and sufficient habitat. © Brooks/Cole Publishing Company / ITP

Conservation Biology 1. Habitat fragmentation is the process by which human activity breaks natural ecosystems into smaller and smaller pieces of land called habitat fragments. one concern is whether remaining habitat is of sufficient size and quality to maintain viable populations of wild species; large predators, such as grizzly bears, and migratory species, such as bison, require large expanses of continuous habitat; habitat fragments are often compared to islands, and principles of island biogeography are often applied in habitat conservation. © Brooks/Cole Publishing Company / ITP

I. Human Impacts on Ecosystems Habitat degradation and fragmentation Simplifying natural systems (monocultures) Wasting Earth’s primary productivity Genetic resistance Eliminating predators Introducing non-native species Overharvesting renewable resources Interfering with cycling and flows in ecosystems

Human Impacts on Ecosystems Some principles for more sustainable lifestyles: we are part of, not apart from, Earth's dynamic web of life; our lives, lifestyles, and economies are dependent on the sun and earth; we never do merely one thing; everything is connected to everything else; were are all in it together. According to environmentalist David Brower we need to focus on "global CPR –– that's conservation, preservation, and restoration". © Brooks/Cole Publishing Company / ITP

Human Footprint on Earth’s Land Surface Fig. 8-12, p. 169

I. Four Principles of Sustainability Solar Energy Population Control PRINCIPLES OF SUSTAINABILITY Nutrient Recycling Biodiversity Fig. 8-13, p. 170

Learning Sustainability from Nature Dependence on nature Interdependence Unpredictability (see Connections on p. 170) Limited resources Recycle wastes

Principles of Sustainability Runs on renewable solar energy. Recycles nutrients and wastes. There is little waste in nature. Uses biodiversity to maintain itself and adapt to new environmental conditions. Controls a species' population size and resource use by interactions with its environment and other species. Principles of Sustainability How Nature Works Lessons for Us Rely mostly on renewable solar energy. Prevent and reduce pollution and recycle and reuse resources. Preserve biodiversity by protecting ecosystem services and preventing premature extinction of species. Reduce births and wasteful resource use to prevent overload and depletion and degradation of resources. Solutions: Implications of the Principles of Sustainability Fig. 8-14, p. 171

J. Ecosystem Restoration Can we restore damaged ecosystems? yes, in some cases; but prevention is easier; natural restoration is slow relative to human life spans; active restoration can repair and protect ecosystems, but generally with considerable effort and expense; example: in Sacramento, California, rancher Jim Callender restored a wetland by reshaping land and handplanting native plants; man of the native plants and animals are now thriving there; restoration requires solid understanding of ecology; it is not possible to undo all ecological harm, e.g., we can't foster recovery of an extinct species. © Brooks/Cole Publishing Company / ITP

Mark-Recapture Lab re ^ Example:

Initial Day 1 Day 2 Day 3 Day 4 Day 5 Control 1 2 3 4 5 C Avg Exp 1 Exp Avg