Irritability, Biology

Assignment Help:

Irritability

If a bright torch of light is flashed across your eyes, you close your eyes instinctively. The bright light acts as a stimulus (pl, stimuli) and closing your eyes is the response or irritability. Irritability is the organism's response to a stimulus by complex adaptive activity, and is one of the most important characteristics of living organisms. All living, things are capable of responding to different kinds of stimuli. Some of the common stimuli are light, heat, gravity, sound and various chemicals. The stimuli may be external i:e., in the environment outside the body or internal i.e., in the environment within the cells or around the cells but within the body. In higher animals there are highly special sense organs for-receiving specific stimuli, as the human eye or ear.

In simple organisms, such highly specialized organs or even specialized cells may be absent, though the whole organism may respond to stimuli. At first you may think that plants do not respond to stimuli. However, on close examination you will note that plants also respond to stimuli such as light, gravity and water by orienting their growth towards or away from the stimuli. Some plants, like Mimosa (sensitive plant), Venus's fly trap respond to touch just like animals. Response of an organism to stimuli involves coordination. Even the simplest organism consists of several parts and each of these must do the right thing and work in harmony for an adaptive response. In animals, nervous and endocrine systems coordinate to bring about responses accomplished by the effectors. Muscle and glands are the important effectors in animals. Plants have no nervous system and rely mainly on hormones for their coordination. The ability to respond to stimuli or Irritability is not shown by non-living things.

1328_Irritability.png

Figure: A few plants, such as the Venus's flytrap, can respond to the touch of an insect by trapping it This figure shows a leaf of the Venus's flytrap attracting and capturing an insect. The leaves of this plant have a scent that attracts insects. When trigger hairs on the leaf surface sense the presence of an insect, the leaf, hinged along its midrib, folds. The edges come together and hairs interlock, preventing the prey from escaping. The leaf then secretes enzymes that kill and digest the insect.


Related Discussions:- Irritability

Why tpp and ttp are vital for the nerves and cardiac tissues, Why TPP and T...

Why TPP and TTP are vital for the nerves and cardiac tissues? TPP and TTP are interconvertible and arc involved in carbohydrate metabolism. As discussed above, when there is in

Importance of primary prevention of diabetes mellitus, Q. Importance of Pri...

Q. Importance of Primary prevention of diabetes mellitus ? Primary prevention has been found to be cost effective in the long run as it reduces unwarranted human suffering. Pre

Simple or unilayered epithelia, SIMPL E EPITHELIA (UNILAYERED EPITHELIA) -...

SIMPL E EPITHELIA (UNILAYERED EPITHELIA) - 1 .      SIMPLE SQUAMOUS EPITHELIUM (PAVEMENT EPITHELIUM) - It is composed of large flat cells whose edges fit closely toge

Define absorption, Define Absorption, Storage and Elimination of niacin? ...

Define Absorption, Storage and Elimination of niacin? Nicotinic acid and nicotinamide are rapidly absorbed from the intestine rather than the stomach. At low concentrations, a

Explain phylum myxornycetes, Phylum Myxornycetes 1) They are known as c...

Phylum Myxornycetes 1) They are known as cellular slime moulds mostly grow in damp places e.g. soil and rotting tree trunks. 2) They have a curious life-cycle in which free

Enumerate about the diseases insomnia, Enumerate about the diseases Insomni...

Enumerate about the diseases Insomnia The results from studies of people, who claim that they do not sleep, or wake up frequently from sleep show that their insomnia can have m

What is the sterile technique, Sterile Technique Every effort should be...

Sterile Technique Every effort should be made to conduct implant surgery under sterile operating conditions. Chlorhexidine 0.2% is used as a pre-operative mouthwash and skin pr

Name some standard activation energy, The standard free energy change and s...

The standard free energy change and standard activation energy for four biochemical reactions are listed in the table below: A few interpretations are given below. Between thes

What are the secondary roots, What are the secondary roots? In origin how t...

What are the secondary roots? In origin how the secondary roots differentiate from shoots? The Secondary roots are ramifications of the primary (major) root. The secondary root

Use of examination gloves, Q. Use of Examination Gloves? Examination Gl...

Q. Use of Examination Gloves? Examination Gloves - latex, vinyl, nitrile, neoprene Gloves are worn whenever contact with blood, saliva, mucous membranes or blood/saliva-cont

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd