Today’s Plan: 5/4/2010

Today’s Plan: 5/4/2010 • Bellwork: Housekeeping/Test corrections (10 mins) • AP Lab 12-DO • Ecology notes

Today’s Plan: 5/5/2010 • Bellwork: Discuss what we’re accomplishing in the lab (10 mins) • Finish DO Lab Data collection (40 mins) • Notes (the rest of class)

Today’s Plan: 5/6/2010 • Bellwork: Finish AP Lab 12 Data collection (20 mins) • Finish AP Lab 12 questions and Test corrections (30 mins) • Continue with notes (the rest of class)

Today’s Plan: 5/7/2010 • Bellwork: Work on the “Can we feed the world’s population?” sheet (30 mins) • Notes (the rest of class)

Today’s Plan: 5/10/2010 • China Video (60 mins) • Finish misc. work (the rest of class)

Today’s Plan: 5/11/2010 • Finish Ecology Notes (30 mins) • Entry document for Final project (15 mins) • Class K/NTK list (15 mins) • Grouping and norm establishment (the rest of class)

Today’s Plan: 5/12/2010 • Bellwork: Q&A (10 mins) • Ecology test (the rest of class) • If you finish early, work on your project!

5/13-5/19/2010 • Work with your group on your final project • I’ll put out a workshop sign up for your NTKs each day. The last 30 mins, I’ll do the workshops you ask for.

5/20-21 • Prepare for your presentations (5 mins) • Group project presentations (the rest of class)

Ecology • This is the study of the distribution, abundance, and interactions of organisms within their environments. • Levels of ecology: • Organism • Population • Community • Ecosystem • Biosphere

Organismal ecology Population ecology Figure 50-1 How and why does population size change over time? How do individuals interact with each other and their physical environment? Each female salmon produces thousands of eggs. Only a few will survive to adulthood. On average, only two will return to the stream of their birth to breed Salmon migrate from saltwater to freshwater environments to breed Community ecology Ecosystem ecology How do energy and nutrients cycle through the environment? How do species interact, and what are the consequences? Salmon die and then decompose, releasing nutrients that are used by bacteria, archaea, plants, protists, young salmon, and other organisms Salmon are prey as well as predators

Population Ecology • Demography-the study of poulations over time, including categories into which the organism falls • For individuals in populations: • Life expectancy/Life tables • Immigration/emigration • For whole populations: • Density=# individuals/area • Dispersion=where you find the individuals in that area • Age Structure=Bar graph showing ages and genders of individuals in the population • Reproductive rate, r (growth rate)=births-deaths/N • N=population size • Survivorship curve (3 types) • Biotic potential=maximum growth possible for the population under ideal conditions (includes things like reproductive age, clutch size, frequency of reproduction, survival rate of offspring)

Distribution of cattle is limited by distribution of tsetse flies. Figure 50-30a Distribution of tsetse fly (red) The two distributions have little overlap (purple) Distribution of cattle (blue)

Figure 52-1-Table 52-1

Figure 52-15 Developed country (Sweden) Developing country (Honduras) 2050 projections 2050 projections 2000 data 2000 data

Three general types of survivorship curves Figure 52-2a High survivorship Type I Low survivorship Type II Steady survivorship Low survivorship Type III High survivorship

Limiting factors • Limiting factors are elements of an ecosystem that are in short supply and therefore set limits on population size • Carrying Capacity (K)-maximum number of individuals that can occupy an ecosystem • Density-dependent limiting factors-factors whose limiting effects increase as population density increases (ex: disease, famine, etc). Some cause an increase in competition. • Density-independent limiting factors-factors whose limiting effects are not tied to population density (ex: natural disasters, climate, etc)

Growth models • Exponential model-also known as a J curve. Assumes that populations can grow without limit • Logistic model-also known as an S curve. Assumes that populations know what K is, and will act accordingly • This changes the reproductive rate equation: • Change N/Change t=rN(K-N/K) • Notice, K is taken into consideration here • Reality-models are only as good as their assumptions, which means that the graph of real population growth is slightly different.

Density dependence: Growth rate slows at high density. Figure 52-7a Carrying capacity Later growth falls to zero Early growth is rapid Growth begins to slow

Growth and Life History • These growth models are associated with 2 kinds of life-strategies for organisms: • r-selected species=these exhibit rapid, exponential growth. These are often called opportunitstic species because they quickly invade an area, reproduce and die. Offspring mature quickly and are small. (ex: grasses, insects) • K-selected species=these are species whose populations are relatively stable, usually around K. They produce a small number os offspring that are large and require lots of care. They reproduce repeatedly (ex: humans)

Human Population growth • Human population worldwide is reaching 9 billion. It was just 3 billion 100 years ago. • Why the rapid rise? • Increases in food supply and travel-humans have domesticated, bred, and fine-tuned agriculture (from hunter-gatherer to farmer) • Reduction in disease-advances in medicine, like vaccines, antibiotics, etc have dropped the death rate and increased the successful birth rate • Reduction in wastes-sewage systems and water treatment have reduced health hazards • Expansion of habitat-better housing, clothing, etc have made it easier to live in more places

Figure 52-16-Table 52-2

Figure 52-17 Current High Medium Low

Population cycles: Predator/Prey • Predator/prey describes a relationship between a hunter and an individual that is eaten. • In general, changes in the prey population cause similar changes in the predator population since the predator is dependent on the prey. Just keep in mind, the prey are usually predators of the producers, so their population changes are often due to seasonal changes in their prey population.

Figure 52-12 The hare-lynx populations cycle every 11 years, on average; the size of the lynx population lags behind that of the hares Lynx Hare

Community Ecology • Habitat-the area that an organism inhabits within an ecosystem • Niche-the role of the organism within the environment1 species per niche • Gause’s principle of competitive exclusion=when 2 species try to occupy the same niche, there will be competition until one species leaves or dies • Resource partitioning=some species can coexist even though they appear to be competing for the same resources. They are occupying slightly different niches by using the resources in different ways. • Character displacement (niche shift)=as a result of resource partitioning, certain characteristics allow organisms to obtain their partitioned resources more successfully • Realized niche=This is the niche that the organism occupies b/c of resource partitioning. If there were no competitors, they would otherwise occupy their fundamental niche, but because of niche overlap, they must adjust

Consumptive competition Preemptive competition Overgrowth competition Figure 53-2 Space preempted by these barnacles is unavailable to competitors. The large fern has overgrown other individuals and is shading them. These trees are competing for water and nutrients. Encounter competition Chemical competition Territorial competition Few plants are growing under these Salvia shrubs. Grizzly bears drive off black bears. Spotted hyenas and vultures fight over a kill.

Figure 53-4a Competitive exclusion in two species of Paramecium Paramecium aurelia Paramecium caudatum

Figure 53-4b Competitive exclusion occurs when competition is asymmetric … Symmetric competition Asymmetric competition Higher fitness Same fitness Lower fitness

Figure 53-4c … and niches overlap completely. Species 1: Strong competitor Species 2: Weak competitor, driven to extinction

Figure 53-4d When competition is asymmetric and niches do not overlap completely, weaker competitors use nonoverlapping resources. Species 1 (strong competitor) Species 2 (weak competitor) Fundamental niche Realized niche

One species eats seeds of a certain size range. Figure 53-3 Partial niche overlap: competition for seeds of intermediate size Species 2 Species 1

Trophic Relationships • These are the feeding relationships in an ecosystem. • Recall from biology that energy transfer between trophic levels is inefficient-only 10% of the energy is transferred, which affects the amount of biomass and the numbers of individuals at each trophic level. This also means that food chains are rarely more than 5 trophic levels. • Food chain: primary producerprimary consumersecondary consumertertiary consumerdetritovores (decomposers) • Food webs are overlapping food chains in an ecosystem. • Recall the following terms: carnivore, herbivore, omnivore

External energy source, usually solar energy but also chemical energy Figure 54-1 Primary producers (autotrophs) Organisms that can synthesize their own food Abiotic environment The soil, climate, atmosphere, and the particulate matter and solutes in water Consumers Organisms that eat other living organisms Decomposer Organisms that feed on dead organisms or their waste products

Trophic level Decomposer food chain Feeding strategy Grazing food chain Figure 54-5 Quaternary consumer 5 Cooper’s hawk Tertiary consumer 4 Robin Cooper’s hawk Secondary consumer 3 Robin Earthworm Primary decomposer or consumer 2 Bacteria, archaea Cricket Primary producer 1 Dead maple leaves Maple tree leaves

Figure 54-6 Cooper’s hawk Fox Robin Alligator lizard Arrows show direction of energy flow: from organism consumed to consumer Earthworm Millipede Insect larvae (maggots) Bacteria, archaea (many species) Cricket Puffball Pillbugs Bracket fungus Dead animals (many species) Maple tree leaves Dead leaves (many species) Rotting log

Figure 54-7 Production of biomass (g/m2/year) 3 Tertiary consumers 10% Efficiency of energy transfer Secondary consumers 30 15% 20% Primary consumers and decomposers 200 Primary producers 1000

Types of predator/prey relationships • True predators-kills and eats another animal • Parasites-are only predatory if they kill their host • Parasitoid-insects that lay eggs on a host. The larvae are parasitic to the host • Herbivores-yes, they’re technically predators. Some are seed-eaters (granivores), some eat grasses (grazers), and some eat other plant material (browsers)

Avoiding Predation • Organisms have evolved many mechanisms for avoiding predators. • Secondary Compounds-toxic chemicals produced by plants that can make herbivores sick • Camouflage (cryptic coloration)-helps the animal blend into it’s surroundings (some predators use this as well to help them hunt) • Aposematic coloration (warning coloration)-a bright color pattern that advertises that the organism should be avoided (ex: wasp/bee stripes) • Mimicry-organisms resembling each other (shortens the predator’s learning curve) • Mullerian mimicry-dangerous organisms resemble each other • Batesian mimicry-organisms without a defense mechanism resemble a dangerous organism

Figure 53-12 Survival of beetle larvae placed on ant mound Resprouted trees have more defensive compounds. Cottonwood tree felled by beavers

Prey and predator Figure 53-10 Blue mussels Crabs Correlation between predation rate and prey defense

Figure 53-9 Constitutive defenses of animals vary. Camouflage: blending into the background Schooling: safety in numbers Weaponry: fighting back Mimicry can protect both dangerous and harmless species. Müllerian mimics Batesian mimics Paper wasp Bumblebee Honeybee Hornet moth Wasp beetle Hoverfly

Symbiosis-a different kind of relationship • In a symbiotic relationship, organisms closely associate with one another. There are 3 types of symbiosis: • Parasitism-1 organism benefits, the other is harmed • Commensalism-1 organism benefits, the other is neither harmed nor benefitted • Mutualism-both organisms benefit

Figure 53-16-Table-53-1

Coevolution in Relationships • Organisms often respond to changes in other organisms through coevolution. • For example, hummingbirds find nectar by color, so the flowers that attract them are tube-shaped, are bright red, and have virtually no scent • Often, plants can only be pollinated by one type of pollinator, so they evolve together

Biodiversity • This is also called species diversity and can be discussed in terms of • Species richness-number of different species in the community • Relative abundance of different species in the community • This is a measure of heath of an ecosystem • Diseases are specific to the organism • If 1 food source dies, there are others, etc

Figure 53-25 Community 2 Community 3 Community 1 A B C Species D E F Species richness: 6 6 5 Species diversity: 0.59 0.78 0.69

Hotspots in terms of species richness of birds Figure 55-4 Hotspots in terms of endemic species of birds Hotspots in terms of high proportion of endemic plants and high threat

High Impact Species in Communities • Keystone Species-These are not necessarily abundant in a community, but play a part in many interactions within the community. You can tell a keystone species by removing it from the ecosystem and viewing the impact. (ex: sea otters, if removed don’t keep sea urchins in check, and there’s less kelp) • Invasive Species-These are species that invade (usually by being introduced by humans) an ecosystem and replace the species that are naturally there • Dominant Species-These are the most abundant species in an ecosystem, and have the most biomass • Foundation Species-These are also called Ecosystem engineers, and they cause physical changes in their environments. Beavers are examples of this type of species. • Facilitators are foundation species that have a positive impact on the environment

Predator: Pisaster ochraceous Figure 53-18 Prey: Mytilus californianus

Today’s Plan: 5/4/2010