**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?
- H. erectus
- Au. afarensis
- H. habilis
- H. sapiens
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?
- Climbing traits and upright walking cannot be present in one species
- Walking upright and a larger brain appeared together
- A larger brain appeared before walking upright
- Walking upright came while the brain was still chimpanzee-sized
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 slight in the shortest phase and fastest in the longest
- Growth was fastest in the second phase, when body size also grew
- Growth was fastest in the shortest phase, of 0.6 million years
- Growth was steady, so the longest phase added the most
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?
- One date is wrong, because a species starts after the one before it ends
- One date is wrong, because H. erectus lived before H. habilis
- Neither date is wrong, because H. habilis lived until today
- Neither date is wrong; the ranges overlap, so both species lived then
Use the table
Card on Au. afarensis clues.
field entry species Au. afarensis lived 3.85 to 2.95 million years ago footprints trails at Laetoli, 3.6 million years ago, like those of modern humans arms long and strong, with curved fingers for climbing trees Tala sees a card with two clues that seem to disagree. What is the best way to read them?
- The arms show the species was a chimpanzee, not an early human
- The species stood halfway on one line from chimpanzees to humans, so each trait is a blend
- The footprints came from another animal, since climbers cannot walk upright
- The species walked upright and also climbed, so its body mixed traits
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 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
- Line 1: node W is wrong, since the human line came from the chimpanzee tip
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 3: the pace changed from slight to fastest across the phases
- 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 2: brain size did not grow while body size grew
Model tree (simplified, not to scale). Ren claims humans and chimpanzees share a common ancestor. Which claim with its reason is best?
- No, because the chimpanzee tip is drawn beside the human tip, so it is the ancestor
- No, because chimpanzees are alive today and so cannot share an ancestor with humans
- Yes, because node X joins the human line and the chimpanzee line about 2 million years ago
- Yes, because node W joins the human line and the chimpanzee line about 6 million years ago
Noah claims H. erectus and H. sapiens were both living for some of the same years. Which claim with its reason is best?
- Yes, because both began 0.3 million years ago
- No, because H. sapiens came from H. erectus, so H. erectus had ended first
- Yes, because 0.3 to 0.11 million years ago is in both ranges
- No, because H. erectus ended 1.4 million years ago
Card on symbols and language
field entry color symbols (ocher) by 350,000 years ago recording information by 77,000 years ago painted and carved images by 40,000 years ago spoken language does not fossilize, so its date is not known Zee claims fossils show exactly when spoken language began. Which claim with its reason is best?
- No, because language began 6 million years ago, along with walking
- Yes, because ocher from 350,000 years ago is the first spoken word
- No, because speech leaves no fossil; objects give clues
- Yes, because skull fossils record the first words