Open with a single projected image of a rotting log on a forest floor, with fungi, mosses, beetles, and a salamander visible. Ask students: 'Is this an ecosystem? Defend your answer in one sentence on your notecard.' Give 90 seconds of silent writing, then cold-call 3 students. Expect a split: some will say 'no — an ecosystem is a whole forest,' which surfaces the size misconception you'll dismantle today. Others will say 'yes' but struggle to justify it. Do NOT resolve the debate yet — say, 'Hold that answer. By the end of class you'll defend it with the AP definition.' Targets SP 1 (Concept Explanation) and SP 2 (Visual Representations).

1. 7m

   Levels of Ecological Organization

   Content

   Ecology is organized as nested levels, each contained within the next. An individual is one organism. A population is all individuals of one species in one area at one time — for example, all eastern gray squirrels (Sciurus carolinensis) on this campus. A community is all the interacting populations of different species in that area — squirrels plus oaks (Quercus alba) plus red-tailed hawks plus soil bacteria. An ecosystem adds the abiotic factors — the soil, water, sunlight, temperature — that the community interacts with. Above ecosystem sit biome (regional climate-defined systems) and biosphere (all life on Earth). Crucially, an ecosystem is defined by its interactions and boundaries, not by its size: a rotting log with its fungi, beetles, moisture, and decaying cellulose IS an ecosystem, and so is a tidepool, a puddle, or a gut microbiome.

   Delivery

   The nested-circles diagram on the slide anchors this — walk students from the inside out, naming a real campus example at each level. Emphasize that population, community, and ecosystem are NOT synonyms; students routinely conflate them on the AP exam. Ask: 'If I say all the oaks on campus, what level is that?' (population) 'If I add the squirrels and hawks?' (community) 'If I add the soil and rainfall?' (ecosystem). Pre-empt the size misconception explicitly: 'A rotting log qualifies. A Petri dish qualifies. Size is not the criterion — interaction and boundaries are.'

2. 6m

   Abiotic Factors Determine Distribution

   Content

   Abiotic factors are not passive scenery — they set the rules for which species can persist in a place. Every species has a range of tolerance for temperature, moisture, pH, salinity, and light; outside that range, it cannot survive or reproduce. Example: eastern hemlock (Tsuga canadensis) requires cool, moist, acidic soils (pH ≈ 4.5–5.5) and shaded slopes; you will not find it thriving on a sun-baked south-facing limestone ridge, even if seeds arrive there, because soil pH and moisture exclude it. Another example: brook trout require water below ≈ 20 °C and dissolved O₂ above ≈ 6 mg/L; warming a stream by even 3 °C can eliminate the population. The abiotic filter operates first — biotic interactions like competition and predation shape what survives after the filter.

   Delivery

   The two-column biotic/abiotic organizer on the slide gives students a scaffold they'll use in the quadrat activity. Push them past 'sunlight, water, air' — ask for measurable abiotic variables (temperature in °C, soil pH, % soil moisture, wind exposure, salinity). Ask: 'Why don't we find saguaro cactus in Ohio?' — force them to name the specific abiotic factor (winter minimum temperature < −10 °C kills the tissue), not just 'wrong climate.' This directly targets the misconception that abiotic factors are backdrop rather than determinant. Targets SP 1.

3. 6m

   Classifying Species Interactions (+/−/0 Matrix)

   Content

   Species interactions are classified by their net effect on each partner, giving a 2-species matrix with three possible signs: + (benefit), − (harm), 0 (no significant effect). Mutualism is +/+ (mycorrhizal fungi and plant roots — fungi get sugars, plant gets phosphorus). Commensalism is +/0 (cattle egrets following bison — egrets eat flushed insects, bison unaffected). Competition is −/− (two warbler species using the same insect prey in the same tree). Predation and parasitism are both +/− (wolf eats elk; tick feeds on deer). Amensalism is −/0 and is rare. Symbiosis is the umbrella term for long-term close relationships (mutualism, commensalism, parasitism all fall under it). Resource partitioning reduces −/− interactions: MacArthur's warblers feed at different heights and branch positions of the same spruce, occupying different niches on the same tree.

   Delivery

   The matrix chart on the slide (species A effect × species B effect) is the tool students should use for the card sort in Activity 2 and on the AP exam. Model one classification live: 'Clownfish and sea anemone — anemone gives clownfish shelter (+ for clownfish); clownfish drives off polyp-eating fish and drops food scraps (+ for anemone). +/+, mutualism.' Warn students that AP FRQs often disguise interactions in unfamiliar organisms — they must reason from effects, not from memorized examples. Directly address the misconception that interactions are 'always competition': explicitly point to the +/+ and +/0 quadrants.

1. 22m

   Schoolyard Quadrat Survey and Ecosystem AnalysisLab

   Targets SP 4 (Scientific Experiments), SP 5 (Data Analysis), and SP 2 (Visual Representations). Pair students and assign each pair a numbered 1 m × 1 m quadrat location outside the building (mix of sunny lawn, shaded bed under a tree, edge of pavement, mulched bed). Distribute the handout below on a clipboard. Give 12 minutes outside for data collection, 8 minutes inside for analysis and posting. Walk between quadrats to check that abiotic measurements are in reasonable units and that students are naming species at least to a functional group (grass, broadleaf herb, ant, isopod, etc.). After groups return, each pair posts their quadrat number + one abiotic reading + one biotic count on the shared board (or class spreadsheet). Facilitate a 3-minute whole-class look: 'Which quadrat had the highest species count? What abiotic factor might explain it?' Expect the shaded, moist quadrats to have higher invertebrate diversity — connect this back to the DI 2 point that abiotic factors determine distribution. --- Student handout: Quadrat Survey of a Micro-Ecosystem Quadrat #: ______ Partners: ______ Location description: ______ Part 1 — Abiotic factors (record value AND unit) - Air temperature: ______ °C - Soil temperature (2 cm depth): ______ °C - Soil pH: ______ - Soil moisture (meter reading or dry/moist/wet): ______ - Light level (lux or full sun / partial / shade): ______ - Substrate type (soil, mulch, gravel, pavement, grass thatch): ______ Part 2 — Biotic factors (list every organism or sign of life; estimate count or % cover) - Producers (plants, mosses, algae): ______ - Consumers (arthropods, worms, vertebrate sign): ______ - Decomposers / fungi (mushrooms, mold, leaf litter): ______ - Evidence of past life (dead leaves, feathers, scat): ______ Part 3 — Analysis (answer in complete sentences) 1. Identify the boundaries of your quadrat ecosystem. What makes this a defensible ecosystem unit even though it is only 1 m²? 2. Name TWO abiotic factors from your data and predict how each one limits which organisms appear in your quadrat. Use specific values. 3. Identify ONE possible species interaction you observed or can infer (e.g., ants tending aphids, isopods on decaying leaves, grasses competing for light). Classify it using the +/−/0 matrix and justify. 4. Compare your quadrat's biotic count to one neighboring quadrat with different abiotic conditions. Which abiotic variable best explains the difference? Argue from your data. Rule: every claim must cite a specific measured value from your data table.

   Materials

   • 1 m × 1 m quadrat frames (PVC or string) — one per pair
   • Digital thermometer (air and soil)
   • Soil pH test strips or probe
   • Soil moisture meter (or feel-test rubric)
   • Light meter or smartphone lux app
   • Clipboards, data sheets, pencils
   • Hand lenses
   • Field ID cards for common plants/invertebrates

   Example outputs

   • Quadrat 3 (shaded bed, soil T = 18 °C, pH = 6.2, moist, 800 lux): 4 plant species, 7 isopods, 2 ant species, fungal hyphae under leaves. Boundary defended as the 1 m² of soil-plus-litter column where the same moisture and shade conditions prevail. Interaction: isopods on decaying oak leaves → +/0 commensalism-with-detritus (or +/− if leaves are 'harmed,' though dead — good discussion point). Compared to Quadrat 5 (full sun lawn, soil T = 29 °C, dry), the shaded quadrat has 3× the invertebrate count; soil moisture is the best-explaining variable.
   • Quadrat 5 (sunny lawn, soil T = 29 °C, pH = 6.8, dry, 55,000 lux): 2 plant species (turfgrass, clover), 3 ants, no isopods. Interaction: turfgrass vs. clover competing for water and light, −/−. Prediction: low soil moisture (dry) excludes moisture-dependent decomposers like isopods and earthworms, consistent with the 0 count.

   No-equipment fallback

   Provide a pre-collected dataset from six real campus quadrats (with temperature, soil pH, moisture %, light level, and species list) as a paper handout. Students analyze the dataset using the same Part 3 questions.

2. 8m

   Interaction Card Sort — Rapid +/−/0 Classification

   Targets SP 1 (Concept Explanation) and SP 3 (Text Analysis) — students read a scenario, extract the effect on each partner, and justify a classification. Distribute one set of the 6 cards below to each pair. Students place each card on the +/−/0 matrix mat and write the classification + one-sentence justification on the card. 5 minutes to sort, 3 minutes for a whole-class check. Cold-call one pair per card for their reasoning. Expect the barnacle and remora cards to generate the most argument — good place to reinforce that classification depends on measured EFFECT, not vibes. --- Student card set — Classify each interaction using the +/−/0 matrix For each card: (a) name the effect on species A and species B, (b) give the interaction type, (c) justify in one sentence. Card 1. Mycorrhizal fungi wrap around pine tree roots. The fungi absorb sugars produced by the pine; the pine absorbs phosphorus and water delivered by the extensive fungal network. Card 2. Cattle egrets walk beside grazing bison. As the bison move through the grass, they flush grasshoppers, which the egrets eat. The bison show no measurable change in feeding or weight gain whether egrets are present or absent. Card 3. Two species of Anolis lizards on a Caribbean island both eat the same medium-sized insects on the same tree trunks. Population studies show both species reach lower densities when together than when alone. Card 4. A tick attaches to a white-tailed deer, feeds on the deer's blood for several days, and transmits a pathogen that causes chronic weight loss. Card 5. Barnacles attach to the skin of a gray whale. The barnacles filter-feed on plankton as the whale swims. Studies find no measurable effect on the whale's swimming energetics or health at typical barnacle loads. Card 6. MacArthur's warblers — five species — all feed in the same spruce trees but at different heights and on different parts of the branches. Each species maintains stable populations without excluding the others. Rule: cite the effect on BOTH partners before naming the interaction type.

   Materials

   • Printed card sets (one per pair)
   • +/−/0 matrix mat

   Example outputs

   • Card 1: A = fungi (+, gets sugars), B = pine (+, gets P and water). Type = mutualism (+/+).
   • Card 3: A = Anolis species 1 (−, lower density), B = Anolis species 2 (−, lower density). Type = competition (−/−). Card 6 shows the resolution — resource partitioning.

1. Which of the following correctly orders ecological levels from smallest to largest scope? A) Community → Population → Ecosystem → Biosphere B) Population → Community → Ecosystem → Biosphere C) Ecosystem → Community → Population → Biosphere D) Population → Ecosystem → Community → Biosphere

   multiple choiceB. A single-species population is contained within a multi-species community, which is contained within an ecosystem (community + abiotic factors), which is contained within the biosphere. Targets SP 1.

2. Oxpecker birds perch on the backs of impala in the African savanna. The oxpeckers eat ticks and other parasites from the impala's hide. Recent studies also show oxpeckers occasionally peck at open wounds, slowing healing. Based on this description, classify the oxpecker–impala interaction and justify using the effect on each species.

   short answerThe interaction is best classified as facultative mutualism trending toward parasitism, depending on wound presence. Effect on oxpecker: + (gains food from ticks and blood). Effect on impala: mixed — + when parasites are removed, − when wounds are aggravated. Full-credit answers must cite both effects and acknowledge that classification depends on measured net effect, not just the 'cleaning' vibe. Targets SP 3 (Text Analysis) and SP 1.

3. Eastern hemlock (Tsuga canadensis) is restricted to cool, moist, acidic soils (pH 4.5–5.5) on north-facing slopes in the Appalachians. Explain how TWO specific abiotic factors limit the distribution of this species, and predict what would happen to a local hemlock population if summer stream/soil temperatures rose by 4 °C over 30 years.

   short answerFull-credit response identifies two specific abiotic factors with values — e.g., (1) soil pH: hemlock requires acidic soils around pH 4.5–5.5; alkaline or neutral soils exclude seedling establishment. (2) Temperature/moisture: hemlock requires cool, moist microclimates typical of north-facing slopes; south-facing slopes exceed its thermal/moisture tolerance. Prediction: a 4 °C rise would push local conditions outside the tolerance range, causing seedling mortality, reduced regeneration, and eventual local extirpation as the abiotic filter tightens. Targets SP 1 and SP 7 (Environmental Solutions).

4. Return to the rotting log from the start of class. In 2–3 sentences, defend whether it qualifies as an ecosystem using the AP definition.

   short answerYes — a rotting log qualifies as an ecosystem because it contains a community of interacting populations (fungi, beetles, isopods, salamanders, bacteria) interacting with abiotic factors (moisture, temperature, decaying cellulose as substrate, pH of the wood). Size is not the criterion; interaction and definable boundaries are. This directly resolves the size misconception. Targets SP 1.

• ☐1 m × 1 m quadrat frames — one per pair (PVC or string frames)
• ☐Digital thermometers (air and soil probe)
• ☐Soil pH test strips or pH probe
• ☐Soil moisture meters (or moisture rubric)
• ☐Light meter or smartphone lux app
• ☐Clipboards, pencils, printed quadrat data sheets
• ☐Hand lenses
• ☐Field ID reference cards for common local plants and invertebrates
• ☐Printed interaction card sets and +/−/0 matrix mats (one per pair)
• ☐Notecards for hook prediction
• ☐Printed formative assessment