**Optional (FL only).** Trends in human evolution
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
A skull is dated to 1.6 million years ago and its brain is 900 cubic centimeters. Milo checks both tables. Which species fits both?
- Au. afarensis
- H. habilis
- H. sapiens
- H. erectus
Read this first
Use the table
Card on Au. afarensis.
field entry lived 3.85 to 2.95 million years ago footprints upright walking trails at Laetoli, 3.6 million years ago arms long and strong, with curved fingers for climbing trees brain size 380 to 450 cubic centimeters, about a chimpanzee's Pia reads the card. What does it show about the order in which two human traits appeared?
- Walking upright came while the brain was still chimpanzee-sized
- Climbing traits and upright walking cannot be present in one species
- A larger brain appeared before walking upright
- Walking upright and a larger brain appeared together
Three phases of brain growth (Smithsonian phases)
phase from (million years ago) to (million years ago) brain growth first 6 2 slight second 2 0.8 with body size third 0.8 0.2 fastest Luz works out how long each phase lasted and compares it with the growth. Which claim fits the table?
- Growth was steady, so the longest phase added the most
- Growth was fastest in the shortest phase, of 0.6 million years
- Growth was slight in the shortest phase and fastest in the longest
- Growth was fastest in the second phase, when body size also grew
Fossils of H. habilis and H. erectus are both found in rock dated 1.6 million years ago. Kira thinks one date must be wrong. What is the best reply?
- Neither date is wrong; the ranges overlap, so both species lived then
- One date is wrong, because a species starts after the one before it ends
- Neither date is wrong, because H. habilis lived until today
- One date is wrong, because H. erectus lived before H. habilis
Au. afarensis lived before H. habilis. Jun says that proves Au. afarensis was the parent of H. habilis. What is the best reply?
Use the picture in question 4.
- Right: H. habilis lived while Au. afarensis was still living
- Dates do not show parentage; early human relations are still debated
- Wrong: Au. afarensis lived after H. habilis
- A species that lives earlier must be the parent of the one after it
Use this
Model tree (simplified, not to scale). Tips from left to right: human, chimpanzee, bonobo. Node W is the root, where human and node X branch apart. Node X is where chimpanzee and bonobo branch apart. Node W is about 6 million years ago. Node X is about 2 million years ago. Notebook: Notes on the model tree (classmate's notebook), 4 lines. Columns: line, entry. Line 1: Node W is the shared ancestor of the human, chimpanzee and bonobo lines. Line 2: Node X is where the chimpanzee and bonobo lines meet, about 2 million years ago. Line 3: Node W is about 6 million years ago. Line 4: The chimpanzee tip is the ancestor of the human tip, since the two sit side by side.
Ari reads a classmate's notebook about the model tree. Which line has the mistake?
- Line 1: node W is wrong, since the human line came from the chimpanzee tip
- Line 2: node X is where the human line splits from the chimpanzee line
- Line 3: node W must be about 2 million years ago, the same as node X
- Line 4: side-by-side tips do not make the chimpanzee an ancestor
Table
Earliest evidence for four trends (Smithsonian dates), 4 rows. Columns: trend | evidence from (million years ago). Row 1: walking on two legs | about 6. Row 2: stone toolmaking (sharp flakes for cutting) | at least 2.6. Row 3: handaxes | about 1.76. Row 4: color symbols (ocher) | by 0.35. Notebook: Notes on the trend table (classmate's notebook), 4 lines. Columns: line, entry. Line 1: Walking on two legs has evidence from about 6 million years ago. Line 2: Stone toolmaking (sharp flakes for cutting) has evidence from at least 2.6 million years ago. Line 3: Walking and stone toolmaking began at the same time, so they came as a package. Line 4: Handaxes have evidence from about 1.76 million years ago.
Esme reads a classmate's notebook about the trend table. Which line has the mistake?
- Line 3: the dates are 3.4 million years apart, not the same
- Line 2: stone toolmaking began with walking, about 6 million years ago
- Line 1: walking on two legs began after stone toolmaking
- Line 4: handaxes are older than the first stone toolmaking
Table
Three phases of brain growth (Smithsonian phases). Columns: phase | from (million years ago) | to (million years ago) | brain growth. Row 1: first | 6 | 2 | slight. Row 2: second | 2 | 0.8 | with body size. Row 3: third | 0.8 | 0.2 | fastest. Notebook: Notes on brain growth (classmate's notebook), 4 lines. Columns: line, entry. Line 1: The first phase ran from 6 to 2 million years ago, with slight brain growth. Line 2: The second phase ran from 2 million to 0.8 million years ago, with growth along with body size. Line 3: Brain size grew at one steady pace through the three phases. Line 4: The third phase ran from 0.8 to 0.2 million years ago, with the fastest growth.
Bo reads a classmate's notebook about the brain growth table. Which line has the mistake?
- Line 2: brain size did not grow while body size grew
- Line 1: growth cannot have been slight, since the pace was steady throughout
- Line 4: the third phase was the longest of the three
- Line 3: the pace changed from slight to fastest across the phases
Model tree (simplified, not to scale). Ren claims humans and chimpanzees share a common ancestor. Which claim with its reason is best?
- Yes, because node X joins the human line and the chimpanzee line about 2 million years ago
- No, because the chimpanzee tip is drawn beside the human tip, so it is the ancestor
- Yes, because node W joins the human line and the chimpanzee line about 6 million years ago
- No, because chimpanzees are alive today and so cannot share an ancestor with humans
Noah claims H. erectus and H. sapiens were both living for some of the same years. Which claim with its reason is best?
- No, because H. erectus ended 1.4 million years ago
- Yes, because 0.3 to 0.11 million years ago is in both ranges
- No, because H. sapiens came from H. erectus, so H. erectus had ended first
- Yes, because both began 0.3 million years ago
