Exam (elaborations)
JUNE 2024 4bi1-2b QP Edexcel IGCSE Biology
JUNE 2024 4bi1-2b QP Edexcel IGCSE Biology
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Please check the examination details below before entering your candidate informationCandidate surname Other names
Centre Number Candidate Number
Pearson Edexcel International GCSE (9–1)
Friday 7 June 2024
Afternoon (Time: 1 hour 15 minutes) Paper
reference 4BI1/2B
Biology
UNIT: 4BI1
PAPER: 2B
You must have: Total Marks
Calculator, ruler
Instructions
•• Use black ink or ball-point pen.
If pencil is used for diagrams/sketches/graphs it must be dark (HB or B).
• Fill in the boxes at the top of this page with your name,
centre number and candidate number.
•• Answer all questions.
Answer the questions in the spaces provided
– there may be more space than you need.
Information
•• The total mark for this paper is 70.
The marks for each question are shown in brackets
– use this as a guide as to how much time to spend on each question.
Advice
•• Read each question carefully before you start to answer it.
Try to answer every question.
• Check your answers if you have time at the end.
Turn over
P75815A
©2024 Pearson Education Ltd.
F:1/1/1/1/1/1/1/
*P75815A0124*
, Answer ALL questions.
Some questions must be answered with a cross in a box . If you change your mind about an
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answer, put a line through the box and then mark your new answer with a cross .
1 Read the passage below. Use the information in the passage and your own
knowledge to answer the questions that follow.
Extinctions
During the evolution of living organisms, most species have become extinct.
Evolution by natural selection means that species constantly replace each other.
The photograph shows the fossilised jaws of a shark called megalodon. Megalodon
was a giant, predatory shark that became extinct 2.6 million years ago.
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(Source: © CHRIS HELLIER / SCIENCE PHOTO LIBRARY)
Some scientists think megalodon was replaced by giant, predatory toothed whales. 5
These whales were the ancestors of modern orcas. Any sharks that remained evolved
to become smaller. As well as the steady loss of species over time, there have been
mass extinction events. Approximately 250 million years ago 90% of all animals and
plants became extinct. The cause of this mass extinction is not known, but one theory
is that it was due to the eruptions of volcanoes. The volcanoes released sulfur dioxide, 10
carbon dioxide and dust into the atmosphere. This caused populations of producer
species to fall, atmospheric carbon dioxide levels to rise, and oxygen levels to fall.
Human activity is now causing another mass extinction. Some scientists estimate that
approximately one million animal and plant species are at risk. To prevent species
loss, cryozoos are being developed. Cryozoos are storage tanks containing samples of 15
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body cells from animals and are kept at a temperature of -170 oC. The cells are put in a
salt and sugar solution and then frozen. If a species becomes extinct, the frozen cells
can be used to clone new animals. The banteng is an endangered breed of cattle.
Banteng body cells have been stored in a cryozoo. These cells have been used with
eggs from another species to successfully produce a living banteng. 20
In the future we may be able to bring back extinct species such as mammoths by
making clones using the remains of frozen mammoths. Scientists need to consider
the advantages and disadvantages of bringing back extinct animals. Currently, the
biodiversity of the world is different from the time when mammoths were alive. Many
natural predators of mammoths are now extinct. Mammoths may have helped to 25
keep methane-releasing soil frozen, reducing the release of the methane. Mammoths
were also an important part of the nitrogen cycle and increased the nutrient content
of low-nutrient Arctic soil.
2
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, (a) Megalodon was an animal.
Which of these features does megalodon share with the fungus yeast?
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1 nuclei present in cells
2 nervous coordination
3 stores carbohydrate as glycogen
(1)
A 1 and 2 only
B 1 and 3 only
C 2 and 3 only
D 1, 2 and 3
(b) Scientists think that the giant, predatory toothed whales that replaced the extinct
megalodon consumed the same sources of food.
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Explain how the evolution of giant, predatory toothed whales may have caused
the extinction of megalodon. (lines 5 to 7)
(3)
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*P75815A0324* Turn over
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