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

Every single living organism carries out the same basic processes – different organisms just carry them out in different ways….

Characteristics of Life

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) – they are PRIMARY PRODUCERS

• Animals need to find an external source of food

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

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

Growth means

the organism develops into an adult all growth is by CELL DIVISION

• 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

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

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

Sensitivity means the ability of an organism to gather information and respond to it (Response)

• 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

Mrs Gren

Animal Cell

Plant Cell

Cells• Animal • Plant

Nucleus

Vacuole

Cell Wall

Chloroplasts-contain Chlorophyll for photosynthesis

Cell Membrane

Parts of a Cell

• Nucleus-Controls the actions of the cell and carries instructions as DNA

• Cytoplasm-Jelly like substance that fills cell

• Membrane-Controls entrance and exit

• Vacuole-Storage

H/W

• Draw a cell with labels on a piece of paper the best ones go on the wall

Differences between Plant and Animal cells

• Plants have cell walls-to hold them up

• Plants have CHLOROPLASTS-to make energy by photosynthesis

• Plants have large vacuoles and animal cells have small vacuoles

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

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

Organs• Tissues can be organised into groups

to form organs, each organ has 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

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…

If living organisms are composed of cells, what do they need in order to grow bigger? ……MORE CELLS !!

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)

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?

Living things

The basic processes and characteristics common to all living organisms: nutrition, respiration, excretion, growth, reproduction, movement and response (MRS GREN)

Recall that living things are composed of cells, tissues, organs and systems, and understand that growth results from cell division

H/W

• P 17,18• Q 2,3,5,9