How new species form
Grade 9 Science Worksheet
Circle the best answer.
Read this first
Leaf types after a river splits a model plant population (model data)
group leaf type generation 2 young left by each plant generation 3 east thick 30 2 60 east thin 70 1 70 west thick 50 1 ? west thin 50 2 100 Ari applies each group's own rule. What number belongs in the blank box for the west group's thick-leaved plants in generation 3?
- 51
- 150
- 50
- 100
Bill types in two model finch groups separated by water (model data)
group bill type generation 2 young left by each finch generation 3 island large 20 3 60 island small 80 1 80 mainland large 20 1 20 mainland small 80 2 160 Bo reads generation 3 of two model finch groups that a stretch of water separates. Which statement matches the table?
- Large-billed finches are 60 of 140 on the island and 20 of 180 on the mainland
- Large-billed finches are the same share on both sides, since both began with 20
- Large-billed finches are 60 of 80 on the island and 20 of 160 on the mainland
- Large-billed finches are 20 of 180 on the island and 60 of 140 on the mainland
Thick-leaved plants per 100 on two sides of a river (model data)
group generation 1 generation 2 generation 3 east 40 30 22 west 40 52 65 Esme predicts generation 4 if the river stays and conditions on each side stay the same. Which prediction fits best?
- Both groups return to 40 in generation 4, because they began as one group
- Both groups become two separate species in generation 4, because the river formed
- East rises above 30 and west falls below 52, so the groups move back together
- East falls below 22 and west rises above 65, so the groups keep moving apart
Model fish in one lake (model data)
group where it finds food who it breeds with group 1 shallow water group 1 only group 2 deep water group 2 only Jun reads a table about model fish that share one lake. Which kind of speciation could this start?
- Allopatric speciation: shallow and deep water form a physical barrier
- Sympatric speciation: the groups share one lake, so no barrier is needed
- Adaptive radiation: one founder species has already produced many species
- No speciation: fish that share a lake cannot form new species
Chromosomes in a model plant meadow (model data)
plant group chromosomes in each body cell interbreeds with ancestor plants? interbreeds with its own group? ancestor plants 6 yes yes new plants 12 no yes Luz reads a table about model plants that share one meadow. Which kind of speciation does it show?
- No speciation: plants in one meadow stay one species
- Allopatric speciation: a barrier in the meadow isolates the new plants
- Sympatric speciation: extra sets of chromosomes isolate the new plants
- Adaptive radiation: one founder species gave rise to many species
Two spotted owl subspecies (real facts)
subspecies where it lives climate northern spotted owl the north cooler than the south Mexican spotted owl the south warmer than the north Noah reads real facts about two owl subspecies. Which statement fits the facts?
- Distance has no effect on whether separated groups go on to become separate species
- They are two species, because they live apart in two places with different climates
- They will be two species within a few generations, since they live in separate places
- They are subspecies living apart in different climates, which may lead to speciation
Darwin's finches (real facts)
fact what is known where they live an island chain, or archipelago, west of Ecuador what differs among species beak shape what Darwin proposed beaks of an ancestral species changed over time to suit different food sources Pia reads real facts about Darwin's finches. Which statement best explains the many finch species?
- Each finch changed its beak shape during its life to suit the food on its island
- The water between the islands made each species at once, with no change in beaks needed
- Each island was settled by a different founder species, which kept its own beak shape
- Descendants of one founder group spread out, and food sources favored different beaks
Steps of a model split, not in order (model data)
letter step A The groups can no longer interbreed, so there are two species B A new lake splits one rodent population into two groups C Over many generations each group gains different alleles and faces different conditions D Alleles stop moving between the two groups Ren puts the steps of allopatric speciation in order, first to last. Which order is correct?
- D, B, C, A
- B, C, D, A
- B, D, C, A
- B, A, D, C
Steps of a model valley split, not in order (model data)
letter step A Mutation and natural selection change each group in its own way over generations B Erosion cuts a new valley that divides one population into two groups C The two groups can no longer interbreed, so each is its own species D The groups share no alleles, since individuals cannot cross the valley Tala puts the steps of a model valley split in order, first to last. Which order is correct?
- B, C, D, A
- B, D, A, C
- B, D, C, A
- A, B, D, C
Steps of a model island split, not in order (model data)
letter step A Few alleles move between the island group and the mainland group B The island group and the mainland group can no longer interbreed C Over many generations the two groups change in different ways D A few seeds float to an island and start a new group Zee puts the steps of an island split in order, first to last. Which order is correct?
- D, B, A, C
- D, A, C, B
- D, C, A, B
- A, D, C, B
