Topic 26 How a change ripples through a food web — what needs James (21)

Topic 26 · How a change ripples through a food web · Type 1 · tests LIF5-015

EasyMCQType 1 — two eats-sentences: which of four arrows belongs in the web, or where the named arrow starts and points

A list for a beach in Texas says: the sandpiper eats sand crabs, and the tern eats small fish. Which of these arrows belongs in the food web?

1. a) from the sandpiper to the sand crab
2. b) from the sandpiper to the tern
3. c) from the tern to the small fish
4. d) from the sand crab to the sandpiper ← key

Why it is this type: The arrow points from the food to the one that eats it. The sandpiper eats the sand crab, so the sand crab is the food. So the arrow runs from the sand crab to the sandpiper.

Recommendation: Approve as the exemplar

Topic 26 · How a change ripples through a food web · Type 2 · tests LIF5-015

EasyMCQType 2 — from a list of sentences, how many arrows point into (or start at) a card; on a drawing, how many living things eat the plant; a count typed from a five-sentence list (hard)

A list for a swamp in South Carolina says: the snapping turtle eats small fish, ducklings and water snakes. How many arrows point into the snapping turtle card?

1. a) 1
2. b) 2
3. c) 3 ← key
4. d) 4

Why it is this type: Each sentence of who eats what becomes one arrow, from the food to the one that eats it. The snapping turtle eats three foods. So three arrows point into the snapping turtle card.

Recommendation: Approve as the exemplar

Topic 26 · How a change ripples through a food web · Type 3 · tests LIF5-015

EasyMCQType 3 — what a finished drawing says about a card with arrows out and none in, or in and none out; what to do when a name is written twice

In a finished food web, the dandelion card has three arrows going out and none pointing in. What does the drawing say about the dandelion?

1. a) The dandelion eats three living things.
2. b) Nothing eats the dandelion.
3. c) The dandelion is in the wrong place.
4. d) Three living things eat the dandelion. ← key

Why it is this type: An arrow points from the food to the one that eats it. Three arrows start at the dandelion, so three living things eat it; none points in, so nothing is drawn as the dandelion's food. So three living things eat the dandelion.

Recommendation: Approve as the exemplar

Topic 26 · How a change ripples through a food web · Type 4 · tests LIF5-015

MediumMCQType 4 — the one arrow drawn the wrong way; the one arrow missing; the one listed sentence with no arrow (hard)

Here is a food web for a Florida marsh, with one arrow missing. The list says the alligator eats muskrats: which arrow is missing?

1. a) from the alligator to the muskrat
2. b) from the marsh plants to the alligator
3. c) from the muskrat to the alligator ← key
4. d) from the water beetle to the alligator

Why it is this type: The arrow points from the food to the one that eats it. The alligator eats the muskrat, so the muskrat is the food. So the missing arrow runs from the muskrat to the alligator.

Recommendation: Approve as the exemplar

Topic 26 · How a change ripples through a food web · Type 5 · tests LIF5-015

MediumMCQType 5 — which sentence the drawing shows

Here is a food web for a Florida marsh. Which sentence does this drawing show?

1. a) The water beetle eats ibises.
2. b) The alligator eats marsh plants.
3. c) The marsh plants eat water beetles.
4. d) The ibis eats water beetles. ← key

Why it is this type: The arrow points from the food to the one that eats it. An arrow runs from the water beetle to the ibis. So the drawing shows that the ibis eats water beetles.

Recommendation: Approve as the exemplar

Topic 26 · How a change ripples through a food web · Type 6 · tests LIF5-016

EasyMCQType 6 — one living thing goes up or down: what happens to the next link, told in a sentence (easy) or read off a drawn web (medium)

On a Florida beach, the ghost crab eats sand fleas. One summer there are far fewer ghost crabs: what happens to the number of sand fleas?

1. a) more ← key
2. b) fewer
3. c) the same
4. d) you cannot tell

Why it is this type: The sand flea is the ghost crab's food. Back, the change goes the opposite way. Fewer ghost crabs eat fewer sand fleas, so there are more sand fleas.

Recommendation: Approve as the exemplar

Topic 26 · How a change ripples through a food web · Type 7 · tests LIF5-016

MediumMCQType 7 — to predict the next link, which way do you follow the arrow

Here is a food web for a mountain forest in Idaho. There are more wolverines this year: to predict what happens to the grouse, which way do you follow the arrow from the wolverine?

1. a) forward, to the eater
2. b) back, to the food ← key
3. c) sideways, to the plant
4. d) both ways at once

Why it is this type: The arrow runs from the grouse to the wolverine, so the grouse is the wolverine's food. From the wolverine to the grouse is back, to the food. So you follow the arrow back.

Recommendation: Approve as the exemplar

Topic 26 · How a change ripples through a food web · Type 8 · tests LIF5-016

MediumMCQType 8 — the correct reason for a stated next-link outcome

In a Montana river, the osprey eats whitefish. One year there are far fewer whitefish, and the next year fewer ospreys nest by the river: what is the correct reason there are fewer ospreys?

1. a) More ospreys were eaten.
2. b) The whitefish ate the ospreys' eggs.
3. c) The river had more water in it.
4. d) The ospreys had less to eat. ← key

Why it is this type: The arrow runs from the whitefish to the osprey, so the osprey is the eater. Forward, the change goes the same way: fewer whitefish means less to eat. So the correct reason is that the ospreys had less to eat.

Recommendation: Approve as the exemplar

Topic 26 · How a change ripples through a food web · Type 9 · tests LIF5-016

Hardmulti-selectType 9 — the set of eaters with less to eat when one food falls; the set of foods that fall when one eater rises

In a Wisconsin lake, the pike eats bluegill and sunfish, and the mink eats bluegill too. One year there are far fewer bluegill. Which living things have less to eat? Select every one.

1. a) the pike ← key
2. b) the mink ← key
3. c) the sunfish
4. d) the water plants

Why it is this type: Two arrows start at the bluegill: to the pike and to the mink. Forward, the change goes the same way: both eaters have less to eat. The sunfish is not an eater of bluegill, so its food does not change.

Recommendation: Approve as the exemplar

Topic 26 · How a change ripples through a food web · Type 10 · tests LIF5-017

MediumMCQType 10 — two links away, what happens

On a Maine seashore, the gull eats crabs, and crabs eat mussels. One year there are far more gulls: two links away, what happens to the number of mussels?

1. a) more ← key
2. b) fewer
3. c) the same
4. d) you cannot tell

Why it is this type: Link 1: back from the gull to the crab, the opposite way: fewer crabs. Link 2: back from the crab to the mussel, the opposite way: more mussels. So two links away there are more mussels.

Recommendation: Approve as the exemplar

Topic 26 · How a change ripples through a food web · Type 11 · tests LIF5-017

MediumMCQType 11 — which living thing changes at the first (or second) link

On a Maine seashore, the gull eats crabs, crabs eat mussels, and mussels eat tiny floating plants. The gulls go down: which living thing changes at the second link?

1. a) the crabs
2. b) the tiny floating plants
3. c) the sand
4. d) the mussels ← key

Why it is this type: A change ripples one link at a time. The crabs are one link from the gull, and the mussels are one link from the crabs. So the mussels change at the second link.

Recommendation: Approve as the exemplar

Topic 26 · How a change ripples through a food web · Type 12 · tests LIF5-017

HardMCQType 12 — three links away, what happens; two links away on a drawn web; the set that ends up fewer after three links

In a Georgia pond, the catfish eats sunfish, sunfish eat water fleas, and water fleas eat tiny floating plants. One year the catfish are gone. Three links away, what happens to the tiny floating plants?

1. a) more ← key
2. b) fewer
3. c) the same
4. d) you cannot tell

Why it is this type: Link 1: back from the catfish to the sunfish, the opposite way: more sunfish. Link 2: back from the sunfish to the water flea, the opposite way: fewer water fleas. Link 3: back from the water flea to the tiny floating plants, the opposite way: more tiny floating plants.

Recommendation: Approve as the exemplar

Topic 26 · How a change ripples through a food web · Type 13 · tests LIF5-017

HardMCQType 13 — the correct reason for an outcome two links away, the middle link left unsaid

In an Iowa cornfield, the skunk eats beetle grubs, and the grubs eat corn roots. One year the skunks go down, and the next year there are fewer corn roots left. What is the correct reason there are fewer corn roots?

1. a) The skunks ate the corn roots.
2. b) More grubs ate more corn roots. ← key
3. c) The corn had less rain.
4. d) The grubs ate fewer corn roots.

Why it is this type: Link 1: fewer skunks eat grubs, so there are more grubs. Link 2: more grubs eat more corn roots, so there are fewer corn roots left. So the correct reason is that more grubs ate more corn roots.

Recommendation: Approve as the exemplar

Topic 26 · How a change ripples through a food web · Type 14 · tests LIF5-017

HardtypedType 14 — how many links one living thing is from another

On a Maine seashore, the gull eats crabs, and crabs eat mussels. Type how many links the mussel is from the gull.

Accepted answers (typed): 2 / 2 links / 2 link / 2 links away / the 2 / the 2 links; wrong_fb for 1 and 3.

Why it is this type: Gull to crab is one link. Crab to mussel is a second link. So the mussel is 2 links from the gull. (nearest: none on the lesson side — the lesson counts links aloud ("one change rippled three links") and never asks for the count)

Recommendation: Approve as the exemplar