Eduqas GCSE Geology · 2.5

The Origin and Development of Life on Earth

Revision questions with answers for 2.5 The Origin and Development of Life on Earth in Eduqas GCSE Geology (spec C480QS). Practise with flashcards, a topic quiz, a random quiz across the course, 5 crosswords, Five Degrees, Associations, or read every question and answer below.

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Question 1
Approximately when does the specification suggest life probably originated?
Answer:
Around 3,500 Ma, or 3.5 billion years ago.
Question 2
Where does the specification suggest life probably originated?
Answer:
In oceans or hydrothermal pools; the precise origin is uncertain.
Question 3
What is a black smoker?
Answer:
A hydrothermal vent on the ocean floor that releases hot, mineral-rich fluid, producing a dark plume.
Question 4
Why are hydrothermal environments considered possible settings for early life?
Answer:
They supply water, chemical energy and minerals that could support early biochemical processes.
Question 5
Does the presence of a hydrothermal vent prove life originated there?
Answer:
No. It is a plausible hypothesis; direct evidence for the exact origin remains limited.
Question 6
Why is the early fossil record difficult to interpret?
Answer:
Ancient rocks are rare or altered, and simple soft-bodied organisms are difficult to preserve and identify.
Question 7
What is evolution?
Answer:
Change in inherited characteristics of populations over successive generations.
Question 8
What is biodiversity?
Answer:
The variety of living organisms, including diversity within species and between species.
Question 9
What is a cladogram?
Answer:
A branching diagram showing hypothesised evolutionary relationships among groups.
Question 10
What does a branching point on a cladogram represent?
Answer:
A common ancestor and a divergence into different lineages.
Question 11
Do organisms at the tips of a cladogram necessarily descend from one another?
Answer:
No. They may share a common ancestor while representing separate lineages.
Question 12
Why does a fossil with a later age not have to be an ancestor of every later fossil?
Answer:
It may belong to a separate branch; shared traits and additional evidence are needed to infer relationships.
Question 13
Which appeared earlier in the fossil record: single-celled organisms or multicellular animals?
Answer:
Single-celled organisms.
Question 14
Why did hard parts improve the likelihood of fossilisation?
Answer:
Shells and skeletons resist decay and can be buried and mineralised more readily than soft tissues.
Question 15
Which appeared earlier: fish or terrestrial amphibians?
Answer:
Fish appeared earlier in the fossil record.
Question 16
Which appeared earlier: amphibians or reptiles?
Answer:
Amphibians appeared earlier in the fossil record.
Question 17
Did mammals and birds appear before or after earlier fish and amphibians in the fossil record?
Answer:
Mammals and birds appeared later; many lineages then continued to coexist.
Question 18
How can shared features help construct a cladogram?
Answer:
Shared derived features can indicate groups that inherited traits from a more recent common ancestor.
Question 19
What does a close branching relationship suggest about two groups?
Answer:
They share a more recent common ancestor with each other than with groups branching earlier.
Question 20
A cladogram has branches for fish, amphibians and reptiles. What extra information is needed to determine numerical ages?
Answer:
A dated geological timescale or dated fossil evidence; branch order alone gives relative relationships.
Question 21
What is an extinction?
Answer:
The permanent disappearance of a species or other group.
Question 22
What is a mass extinction?
Answer:
A relatively rapid, widespread loss of many species across different groups and environments.
Question 23
Which mass extinction is named in the specification?
Answer:
The Cretaceous-Palaeogene, or K/Pg, mass extinction.
Question 24
Approximately when did the K/Pg mass extinction occur?
Answer:
About 66 million years ago.
Question 25
What major event is associated with the K/Pg extinction?
Answer:
A large asteroid impact, with severe global environmental effects; other stresses may also have contributed.
Question 26
How could a large impact disrupt food chains?
Answer:
Dust and aerosols reduce sunlight, slowing photosynthesis and reducing food available to other organisms.
Question 27
Did all life disappear at the K/Pg boundary?
Answer:
No. Many groups survived; non-avian dinosaurs became extinct while birds survived.
Question 28
Why can an extinction change later evolutionary patterns?
Answer:
Surviving groups can diversify as environments and ecological opportunities change.
Question 29
How can selective preservation bias our view of past biodiversity?
Answer:
Hard-shelled, abundant or rapidly buried organisms are more likely to be preserved than fragile or rare organisms.
Question 30
Which parts of organisms generally fossilise most readily?
Answer:
Hard parts such as shells, bones and teeth.
Question 31
How does rapid burial favour preservation?
Answer:
It protects remains from scavenging, physical destruction and some decay processes.
Question 32
How do low-oxygen conditions favour preservation?
Answer:
They can slow decay and limit the activity of some decomposers and scavengers.
Question 33
Why do metamorphism and erosion reduce the fossil record?
Answer:
They can alter, deform or destroy fossil-bearing rocks.
Question 34
What is exceptional preservation?
Answer:
Unusually detailed preservation, sometimes including evidence of soft-bodied organisms or soft parts.
Question 35
Why is the Burgess Shale scientifically significant?
Answer:
Its exceptional fossils preserve a diverse range of Cambrian organisms, including soft-bodied forms.
Question 36
Why might a fossil assemblage not represent every organism that lived there?
Answer:
Preservation, transport, exposure and discovery favour some organisms over others.
Question 37
Why can the absence of a fossil from one outcrop not prove a species never lived there?
Answer:
The organism may not have been preserved, exposed or found in that sample.
Question 38
What is Archaeopteryx?
Answer:
A fossil animal showing a combination of features associated with birds and non-avian dinosaurs.
Question 39
Give a bird-like feature of Archaeopteryx.
Answer:
Feathers and wings.
Question 40
Give a reptile-like feature of Archaeopteryx.
Answer:
Teeth, a long bony tail or clawed fingers.
Question 41
Why is Archaeopteryx important to interpreting evolution?
Answer:
Its mixed features provide evidence of evolutionary relationships between birds and other dinosaurs.
Question 42
Does Archaeopteryx prove that living birds evolved from the exact fossil individual found?
Answer:
No. It provides evidence of related evolutionary forms, not proof that a particular fossil was a direct ancestor.
Question 43
What does disarticulated mean for a fossil skeleton?
Answer:
The bones are separated from their original positions relative to one another.
Question 44
Why can reconstructing a dinosaur from incomplete remains be uncertain?
Answer:
Missing or moved bones require interpretation using comparable specimens and may allow more than one reconstruction.
Question 45
How can a fossil footprint add evidence beyond a skeleton?
Answer:
Track shape and arrangement can indicate movement, behaviour or the presence of animals at a location.
Question 46
Can two differently sized footprints conclusively prove two different species?
Answer:
No. Individuals of one species, preservation conditions or ages can also affect footprint size.
Question 47
Who is Lucy?
Answer:
A fossil early hominin, Australopithecus afarensis, represented by a partial skeleton.
Question 48
What evidence from Lucy helps infer upright walking?
Answer:
Features of the pelvis and lower limbs support habitual bipedal movement.
Question 49
Why are partial hominin skeletons interpreted alongside other finds?
Answer:
Combined evidence helps test reconstructions and reduces uncertainty caused by missing bones.
Question 50
Why should a fossil reconstruction distinguish observation from inference?
Answer:
The actual preserved bones are observations; appearance and behaviour beyond them are interpretations.

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