Download OB41 - OB42

1C1
Living things
OB41
identify the basic processes and
characteristics common to all living organisms:
nutrition, respiration, excretion, growth, reproduction,
movement and response
OB42
recall that living things are composed of
cells, tissues, organs and systems, and understand
that growth results from cell division
www.juniorscience.ie
OB41 identify the basic processes and characteristics
common to all living organisms: nutrition, respiration,
excretion, growth, reproduction, movement and
response
Every single living organism carries out
the same basic processes – different
organisms just carry them out in
different ways….
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OB41 identify the basic processes and characteristics
common to all living organisms:
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OB41 basic processes: nutrition
Nutrition means obtaining food
• All living organisms need food as a
source of energy
• Plants can make their own food using
energy from the sun (photosynthesis)
• Animals need to find an external source
of food
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OB41 basic processes: respiration
Respiration means
releasing energy from food
• Glucose in the food is broken down inside
cells, and energy is released
• Most organisms use oxygen for this process –
so it is called aerobic respiration
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OB41 basic processes: excretion
Excretion
means the removal of toxic chemical substances
• toxic substances are poisonous and
may harm cells if not removed
• examples of toxic substances are
carbon dioxide and urea
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NH3
OB41 basic processes: growth
Growth means
the organism develops into an adult
• For micro-organisms, this means
their cell grows to full size before
reproducing
• For multi-celled organisms, this
means that cells divide, organs
grow in size, and systems develop
maturity
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OB41 basic processes: reproduction
Reproduction means
Scientists have a
name for the
“children” of all living
organisms – they say
OFFSPRING
producing more organisms of the species
• Some organisms reproduce from one
parent only – this is called ASEXUAL
reproduction
• Other organisms reproduce by
combining one cell from a male with
one cell from a female – this is called
SEXUAL reproduction
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OB41 basic processes: movement
Movement means
the ability of an organism to change position
• Some organisms can move the entire body
eg single-celled organisms
• Some organisms can move part of the body
eg plants
• Some organisms can move both
their entire body, and each section of the body
eg insects, amphibians, reptiles, mammals
• Most organisms move towards things they need
and away from things that harm them
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OB41 basic processes: response
Response means the ability of an organism to
gather information and respond to it
• Some of the things that cause living organisms
to respond are light, sound, touch, chemicals,
gravity…eg:
• Roots grow downwards in response to gravity,
shoots grow towards light
• Both plants and animals use their sense of
touch when climbing
• Predators use sound and smell to hunt for prey
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OB42 recall that living things are composed of cells,
tissues, organs and systems, and understand that growth
results from cell division
Cells
• Some living things are composed of just a single
cell eg bacteria
• Some living things are composed of a small
number of simple and similar cells eg fungi
• Some living things are composed of very many
cells, with many different structures and functions
eg humans
nerve
cell
muscle cells
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blood cells
bone cells
OB42 recall that living things are composed of cells,
tissues, organs and systems, and understand that growth
results from cell division
Tissues
• Cells that have the same structure and
function form tissues…
• Cells in tissues are usually joined
together
• Animal tissues include muscle, bone
and nerves for movement
• Plant tissues include xylem and
phloem for transport
phloem
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xylem
OB42 recall that living things are composed of cells,
tissues, organs and systems, and understand that growth
results from cell division
Organs
• Tissues can be organised into groups to form
organs, each organs with a particular function
• Plant organs include the ROOT for absorbing
water, LEAF for photosynthesis
• Animal organs include the HEART for pumping
blood, LUNGS for gas exchange
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OB42 recall that living things are composed of cells,
tissues, organs and systems, and understand that growth
results from cell division
Systems
• organs, tissues and cells can be organised
into systems that carry out major functions in
the organism eg:
Reproductive system, Nervous system,
Digestive System, Circulatory system…
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OB42 recall that living things are composed of cells,
tissues, organs and systems, and understand that growth
results from cell division
If living organisms are composed of
cells, what do they need in order to
grow bigger? …
…MORE CELLS !!
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OB42 recall that living things are composed of cells,
tissues, organs and systems, and understand that growth
results from cell division
click to see a
real cell dividing
© A. Kihara (Hosei University)
Cell division takes place in 3 stages…
1. A copy of the nucleus is made
2. The cell membrane grows inwards to divide
the cytoplasm
3. The two new cells then separate
…the new cells then grow to full size
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What do you think?
• Most animals move about while most plants
tend to “stay put” – why?
• Can you suggest one advantage and one
disadvantage of being single-celled?
• Animals have highly developed nervous
systems compared to plants – why?
• A lot of plants have to use the help or wind
or insects for reproduction – why?
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1C1
Living things
OB41
identify the basic processes and
characteristics common to all living organisms:
nutrition, respiration, excretion, growth, reproduction,
movement and response
OB42
recall that living things are composed of
cells, tissues, organs and systems, and understand
that growth results from cell division
www.juniorscience.ie