How new species form
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Read this first
Thick-leaved plants per 100 in two groups divided by a river (model data)
leaf type generation 1 generation 3 east generation 3 west generation 5 east generation 5 west thick 40 22 65 10 80 thin 60 78 35 90 20 Ari reads generations 1, 3 and 5 for two groups divided by a river. Which conclusion does the table support?
- Both groups changed in the same direction, so the river had no effect on them
- The groups are now separate species, because their leaf types differ from each other
- The river changed each plant's leaves, so the whole population shifted in one step
- The groups moved apart in leaf type; the table cannot show if they interbreed
Animals crossing a barrier in one generation, in two model cases (model data)
case barrier animals crossing flying insects in two valleys open air 30 rodents on two sides of a new lake water 0 Bo compares two model cases. Which case is more likely to lead to speciation, and why?
- The insects, because with 30 crossing, the two groups are cut off from each other
- The rodents, because with none crossing, alleles are not shared between them
- Neither, because both cases happen in one region of land, so no isolation arises
- The rodents, because any barrier makes a new species at once, whatever the crossing
Two plant groups in one model meadow (model data)
plant group chromosomes in each body cell flowering months interbreeds with ancestors? ancestor plants 6 April and May yes new plants 12 April and May no Esme reads a table about one meadow. The new plants cannot interbreed with the ancestor plants. What isolates them?
- Nothing yet, since they look like the ancestors and are the same species
- Their doubled chromosome number, since place and flowering time are the same
- Their flowering months, since the two groups reproduce at different times
- A barrier in the meadow, since the two groups live apart from one another there
Abert and Kaibab squirrels (real facts)
fact value kind of group subspecies forest the same kind of pine forest for both what lies between them the Grand Canyon squirrels studied 60 Abert and 62 Kaibab Jun notes that the squirrels' forests match, yet the two groups are separate subspecies. Which explanation fits?
- Each squirrel changed its body to fit its side of the canyon, which made new species
- The canyon stops alleles moving between them, so each group can change on its own
- Groups need different forests to change, so a hidden difference must exist
- The canyon already made them two separate species, so the forests do not matter here
Thick-leaved plants per 100 on two sides of a river (model data)
group generation 1 generation 2 generation 3 east 40 38 37 west 40 41 42 Luz notes that two groups on opposite sides of a river are nearly alike after 3 generations. No plants cross the river. Which explanation fits?
- Barriers do not matter here, since mutation alone changes groups over time
- Three generations is little time; groups need longer apart to change much
- The river failed to separate the groups, since alleles still move across it
- The barrier should have made two separate species by now, so something went wrong
Notebook
Notes on a river and a mouse population (classmate's notebook), 4 lines. Columns: line, entry. Line 1: A new river splits one mouse population into a north group and a south group. Line 2: No mice cross the river, so alleles stop moving between the groups. Line 3: So the north and south groups were two separate species as soon as the river formed. Line 4: Over many generations each group may gain different alleles and face different conditions.
Milo reads a classmate's notebook about a river and a mouse population. Which line has the mistake?
- Line 2: alleles keep moving between the groups, even though no mice cross the river
- Line 1: a river cannot split one mouse population into a north group and a south group
- Line 4: the groups should change into two species within a single generation
- Line 3: a barrier alone does not make species; change takes many generations
Notebook
Notes on a model plant with extra chromosomes (classmate's notebook), 4 lines. Columns: line, entry. Line 1: A plant species has 6 chromosomes in each body cell. Line 2: An error leaves some offspring with 12 chromosomes in each body cell. Line 3: These new plants can interbreed with their own kind, but only after thousands of generations. Line 4: They can grow in the same meadow as the ancestor plants.
Noah reads a classmate's notebook about a model plant with extra chromosomes. Which line has the mistake?
- Line 1: a plant species cannot have 6 chromosomes in each body cell of the plant
- Line 3: the new plants are isolated from the ancestors right away, with no wait
- Line 2: an error cannot leave offspring with more chromosomes in each body cell
- Line 4: plants with different chromosomes cannot grow in the same meadow together
Notebook
Notes on crater-lake cichlids (classmate's notebook), 4 lines. Columns: line, entry. Line 1: Lake Apoyeque is a crater lake that is 1800 years old. Line 2: Genetic evidence shows one cichlid population settled it about 100 years ago. Line 3: Speciation needs a physical barrier, so these fish cannot be forming new species. Line 4: Two populations with different body forms and diets now live in the lake.
Pia reads a classmate's notebook about crater-lake cichlids. Which line has the mistake?
- Line 4: two populations cannot have different diets and body forms
- Line 1: a crater lake is not a place where a population can settle
- Line 2: genetic evidence cannot show when a population settled a lake
- Line 3: speciation can start in one place, without a physical barrier
Two island bird groups with different beaks (real facts)
bird group what differs among species islands Hawaiian honeycreepers beak shape and food source the Hawaiian Islands Darwin's finches beak shape an island chain west of Ecuador Tala judges a claim about Hawaiian honeycreepers and Darwin's finches, which show adaptive radiation. Which claim and reason fit best?
- A barrier made each species at once, since islands are surrounded by open water
- Each bird's beak grew to fit its food during its life, which made a new species
- Each species came from its own founder, since the beak shapes of the species differ
- Many species came from one founder, since new food sources favored different beaks
Flowering months of two model plant groups in one meadow (model data)
group first month last month group A March April group B June July Zee judges a claim about two model plant groups that share one meadow. Which claim and reason fit best?
- Timing can isolate the groups in one meadow, since they flower at different times
- Timing isolation works for animals, but plants cannot reproduce on a schedule
- A barrier is needed to isolate the groups, since a single meadow cannot isolate them
- Flowering times cannot isolate the groups, since both groups share one meadow