Page 24 - 新思维科学学生用书7 样章

1.4 Cells, tissues and organs

Summary checklist

I can give examples of tissues and organs in animals and plants.

I can explain the meanings of the words tissue, organ and organ system.

Project: Cells discovery timeline

This project is about how scientific knowledge
gradually develops over time. You are going to
work in a group to do research, and then use
your findings to help to make a timeline.

Science never stays still. When one scientist makes
a new discovery, this suggests new questions that

other scientists can investigate.

You are going to produce a timeline. The timeline will show
how scientists gradually discovered that all living things are
made of cells.

The list below shows some of the important steps that

occurred. This is the type of microscope
that Robert Hooke used.
In your group, choose one of these steps to investigate.

Make sure that you do not choose the same step as another group.

Help your group to find out more about this step. Then help to produce an illustrated
account of what happened.

Try to include an explanation of how the work of earlier scientists helped this step to
take place.

1625 Galileo Galilei builds the first microscope.
1665 Robert Hooke looks at cork (from tree bark) through a microscope, and
describes little compartments that he calls cells.

1670 Anton van Leeuwenhoek improves the microscope and is able to see living
cells in a drop of pond water.
1833 Robert Brown discovers the nucleus in plant cells.

1838 Matthias Schleiden proposes that all plant tissues are made of cells. Theodor
Schwann proposes that is also true of animal cells.
1845 Carl Heinrich Braun proposes that cells are the basic unit of all life.
1855 Rudolf Virchow says that all cells only arise from other cells.

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