Survival and response

1
Survival and response

• Aim To understand the responses animals and
  plants make in order, to increase their chance of
  survival

2
What changes in the environment do organisms
respond to?
Are these responses fast, slow, long or short
duration
Are these responses chemical or electrical
3
Which chemicals are involved in responses

• Hormone Chemical messages
• Neurotransmitters Chemicals that pass a message
  from one neurone to another at a synapse
• Histamine Released as a result of
  infection/injury causes inflammation due to
  dilation of blood capillaries- plasma containing
  antibodies then escapes into the tissue
• Prostoglandins Hormones which help sperm reach
  the oocyte by causing muscular contractions of
  the uterus and oviducts

4
Which chemicals are involved in responses

• Hormone
• Neurotransmitters 271-272
• Histamine
• Prostoglandins

5
Tropisms

• Tropisms A growth movement in response to a
  directional stimulus
• Keeps the roots and shoots in favourable
  conditions

6
TASKCopy and give explain how these keep the
roots and shoots in favorouble positions for the
plant

• Plant shoots grow towards light positive
  phototrophism
• Plant roots grow away from light (negative
  phototrophism) and towards gravity (positive
  geotrophism)
• Plant roots grow towards water (positive
  hydrotrophism)

7
Auxins

• Plant growth is controlled by the growth hormone
  auxin. The most common type of auxin is IAA.
• Task Using 431 432 summarise how scientists
  discovered how plant growth is regulated

8
Phototrophism

• Auxins (IAA) Indoleacetic acid
• Plant hormone that controls plant growth
• Produced in shoot tips
• Causes elongation of shoot cells

9
Phototrophism

• Light destroys auxin
• - This encourages growth on the shaded side
• - This makes the shoot bend towards the light

10
Geotrophism

• The main plant root always grows downwards
  towards gravity

11
How geotrophism works

• In roots auxin accumulates on the lower side of
  the root
• In roots auxins INHIBIT cell elongation

Cells continue to elongate
Cell elongation inhibited
Auxin accumulates
12
Plant growth factors

• The most common growth hormone is IAA
  Indoleacetic acid (IAA).
• Pg 157 copy final 3 bullet points and the 2
  sentences below it
• Read application and how science works and answer
  the questions as you go through

13
Taxes and Kinesis

• Responses to stimuli (change in the environment)
• Taxes - Directional response to stimulus ie
  moves toward (positive taxes) or away (negative
  taxis to the stimulus
• Kinesis Non directional response to stimulus ie
  speeds up, slows down or changes direction more
  often

14
Task

• Plan an investigation into the kinesis response
  of woodlice to a stimuli
• Title
• Hypothesis