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1C1Living 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

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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: respirationRespiration 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

Excretionmeans 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

NH3

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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 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

Scientists have a name for the

“children” of all living organisms –

they say OFFSPRING

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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

blood cells bone 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

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

xylem

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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

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

Cell division takes place in 3 stages…1. A copy of the nucleus is made2. The cell membrane grows inwards to

divide the cytoplasm3. The two new cells then separate…the new cells then grow to full size

click to see a real cell dividing

© A. Kihara (Hosei University)

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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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1C1Living 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