Basic principles of life
This extends the Std 9–10 ideas of characteristics of living things and biodiversity; here we learn the tools (taxonomic aids) used to study them.
A sand mound gets bigger in the rain, yet we do not say it ‘grows’; a seedling grows from within, so we call it living.
A living being shows metabolism, growth from within, reproduction and response to the surroundings.
In the figure : The figure shows six features around ‘Living’; no single feature alone proves a thing is alive.
Rule 1 : Metabolism — Metabolism = breaking down (catabolism) + building up (anabolism); it supplies energy and molecules.
- Easy : Digesting food to get energy = catabolism.
- Medium : Making proteins to build muscle = anabolism.
- Exam-type (CET) : Q: Is an enzyme reaction in a test tube (in vitro) living? A: No; with no cellular organisation it is just a chemical reaction.
Rule 2 : Growth, ageing, reproduction, response — A living thing grows from within; a sand mound or boulder grows by outside accumulation. Responding to change (responsiveness / irritability) is a unique feature of life.
- Easy : A caterpillar turning into a butterfly is growth and development from within.
- Medium : Mules and sterile worker bees do not reproduce, yet are living.
- Exam-type (CET) : Two cockroaches lie in a classroom; which feature shows if they are alive? Answer: response (they move when touched).
Reproduction is not all-inclusive (mule, sterile bee); metabolism and response are found in all living things.
Writing ‘crystals or sand grow, so they are living’ is wrong; that growth is by outside accumulation. Trap: ‘which is not a property of living?’ often has ‘decay’ as the option.
Memory clue : "M-G-R-R-A-D: Metabolism, Growth, Reproduction, Response, Ageing, Death".
Spot the difference
| Point | Growth of a living thing | Growth of a non-living thing |
|---|---|---|
| From where | From within (cells increase) | By outside accumulation |
| Example | Seedling, chick | Sand mound, boulder |
| Limit | Limited time; then ageing | No set limit |
Practice questions
- 1Name the two parts of metabolism.
- 2Give another name for responsiveness.
- 3Why is a sand mound not living?
- 4How do you say a mule is living though it cannot reproduce?
- 5Which is NOT a property of a living being: a) metabolism b) decay c) growth d) reproduction?
- 6Is a cockroach alive or dead? Which feature will you test?
- 7Why is a test-tube metabolic reaction not called living?
- 8Why is reproduction not an ‘all-inclusive’ feature of life?
Show answers (try them yourself first)
- 1Catabolism and anabolism.
- 2Irritability.
- 3It does not grow from within; sand collects from outside.
- 4It has metabolism, growth and response; reproduction is not the only test.
- 5b) decay.
- 6Response: does it move when touched?
- 7There is no cellular organisation; it is only a chemical reaction.
- 8Some living beings (mule, sterile worker bee) do not reproduce yet are alive.
Herbarium
Pressing a leaf in your notebook keeps it for a year; a herbarium is the scientific version of that habit.
A herbarium (plural herbaria) is a dried plant specimen that is pressed, treated and mounted on a standard-size sheet.
In the figure : The specimen is mounted on the sheet and the information label sits at the lower right corner.
Rule 1 : Making a herbarium — Press → dry → treat → mount on the sheet → add the label.
- Easy : Order of steps: press, dry, mount. Which is first? Pressing.
- Medium : The label carries name, date, place, collector's name and habitat notes.
- Exam-type (CET) : Q: A strictly seasonal plant is to be studied in the lab; best tool? A: Herbarium.
Rule 2 : Uses of a herbarium — A plant can be studied even out of season; plants can be identified and compared.
- Easy : A rainy-season herb can still be viewed in December.
- Medium : A student finds a peculiar plant in Himachal; she can show it to her teacher as a pressed herbarium sheet.
- Exam-type (CET) : Who coined the word? Pitton de Tournefort (in ‘Elemens’); the art was started by Luca Ghini.
Label = lower right corner; the sheet is of a standard size.
Thinking a herbarium holds live plants is wrong; they are dried (live plants = botanical garden).
Memory clue : "HERB-arium = the home of dried HERBs".
Spot the difference
| Point | Herbarium | Botanical garden |
|---|---|---|
| Plants | Dried specimens | Living plants |
| Kept on | Paper sheets | Soil/pots |
| Use | Identification, comparison, record | Live study, conservation |
Practice questions
- 1What is a herbarium?
- 2Where is the label on the sheet?
- 3What does ‘herbaria’ mean?
- 4Name any three details on the label.
- 5Who started the art of herbarium?
- 6How will you study a seasonal plant all year?
- 7Main difference between herbarium and botanical garden?
- 8State the essentials of a good herbarium.
Show answers (try them yourself first)
- 1A pressed, dried specimen mounted on a sheet.
- 2Lower right corner.
- 3Plural of herbarium.
- 4Name, date, place, collector, habitat notes (any three).
- 5Italian taxonomist Luca Ghini (1490–1556).
- 6By making her herbarium sheet.
- 7Dried specimens versus living plants.
- 8A well pressed and dried specimen, a standard sheet and a complete label (name, date, place, collector).
Botanical gardens and museums
A garden has name boards on plants and a science exhibition has specimens in jars; these are the ‘living’ and ‘preserved’ libraries of biology.
A botanical garden grows living plants from many places in a scientific way; a museum is a repository of preserved plant and animal specimens.
In the figure : Left: live plants with a name board; right: a formalin jar and a stuffed bird.
Rule 1 : Botanical garden — Plants are labelled with scientific and common names and grown in vivo (alive).
- Easy : A name board shows two names: scientific and common.
- Medium : In 1543 Luca Ghini set up the world's first botanical garden at Pisa, Italy.
- Exam-type (CET) : Kolkata's banyan tree, more than 255 years old, stands in a botanical garden. Q: Why a greenhouse in the garden? A: To grow plants of other climates under suitable conditions.
Rule 2 : Museum — Specimens are kept in formalin (10–40 % formaldehyde) in transparent jars; large birds and mammals are stuffed (taxidermy).
- Easy : Shells, skeletons and insect boxes are kept in museums.
- Medium : The science of stuffing and preserving animals is taxidermy.
- Exam-type (CET) : Why is shell collecting banned on Andaman beaches? To protect local biodiversity and habitat.
Garden = live (in vivo); museum = preserved; herbarium = dried.
‘Taxidermy = keeping in formalin’ is wrong; it is stuffing and mounting. Trap: do not mix Kew garden with the first garden (Pisa).
Memory clue : "Garden=Alive, Museum=Archive, Herbarium=Dry".
Spot the difference
| Point | Botanical garden | Museum |
|---|---|---|
| Specimens | Living plants | Preserved plants and animals |
| Method | Cultivation, name board | Formalin, taxidermy, drying |
| Use | Live study, conservation | Reference, comparison, teaching |
Practice questions
- 1Which two names are on a plant's board in a garden?
- 2What does in vivo mean here?
- 3Where and when was the first botanical garden?
- 4What is formalin and why is it used?
- 5What is taxidermy?
- 6How is a large animal specimen kept in a museum?
- 7Give two benefits of visiting a botanical garden.
- 8Why are museums called reference hubs?
Show answers (try them yourself first)
- 1Scientific and common name.
- 2In the living state.
- 3Pisa, Italy; 1543.
- 4A 10–40 % formaldehyde solution; to preserve specimens.
- 5Stuffing and preserving birds and mammals.
- 6Stuffed (taxidermy).
- 7You can identify diverse live plants and understand classification and conservation.
- 8Specimens there can be compared to study biodiversity.
Zoological parks and biodiversity parks
In a zoo a tiger lives in an enclosure and we can study its food and behaviour; if people grow a forest on barren land, it is a biodiversity park.
A zoological park keeps wild animals in captivity under conditions like their habitat (ex-situ). A biodiversity park is an ecological assemblage of species forming self-sustaining communities on degraded or barren land.
In the figure : Left: in-situ (in the habitat); right: ex-situ (outside the habitat). A biodiversity park is a model for protecting natural heritage.
Rule 1 : Zoological park (zoo) — Animals get protection and habitat-like conditions; naturalists study food habits and behaviour.
- Easy : Penguins are given a cold environment because it matches their natural habitat.
- Medium : Humboldt penguins at Mumbai's Jijamata Udyan must be acclimatised to the new place.
- Exam-type (CET) : Is a zoo ex-situ or in-situ? Ex-situ (outside the habitat).
Rule 2 : Biodiversity park — It creates self-sustaining species communities on barren land, e.g. Late Uttamrao Patil Biodiversity Park, Gureghar, Mahabaleshwar.
- Easy : Growing native trees on barren land = biodiversity park.
- Medium : Sacred groves: forests conserved in the name of a holy place; IUCN also treats them as sacred natural sites.
- Exam-type (CET) : True or false: ‘A biodiversity park is a model for protecting natural heritage in urban landscape.’ True.
Other record tools: Flora, Manual, Monograph, Catalogue.
Flora = plant life of an area; Monograph = one selected group; Manual = information and keys for identification. Do not swap these.
Memory clue : "FMMC = Flora, Manual, Monograph, Catalogue".
Spot the difference
| Point | Botanical garden | Zoo | Biodiversity park |
|---|---|---|---|
| What it holds | Living plants | Captive wild animals | Self-sustaining species community |
| Type | Ex-situ | Ex-situ | Habitat restoration |
| Example | Kolkata, Kew | Jijamata Udyan | Gureghar |
Practice questions
- 1What is a zoo?
- 2What does a naturalist study in a zoo?
- 3State one feature of a sacred grove.
- 4What is a flora?
- 5Differentiate monograph and manual.
- 6Why are penguins given a cold environment?
- 7Give one difference among botanical garden, zoo and biodiversity park.
- 8Which of zoo and sacred grove is in-situ?
Show answers (try them yourself first)
- 1A place where wild animals are kept in captivity under habitat-like conditions.
- 2Food habits and behaviour.
- 3Forest conserved in the name of a holy place; treated by IUCN as sacred natural site.
- 4Plant life of a particular area at a time.
- 5Monograph = one selected group; manual = identification information and keys for species of an area.
- 6It resembles their natural habitat, so they adapt.
- 7Garden = live plant collection; zoo = captive animals; biodiversity park = self-sustaining community on degraded land.
- 8Sacred grove (forest conserved where it stands); zoo is ex-situ.
Keys and other taxonomic aids
Asking ‘does it have wings? yes/no’ again and again to name an unknown bird is exactly how a key works.
A key is a tool to identify plants and animals. A dichotomous key uses pairs of contrasting characters; each statement is a lead.
In the figure : At each step one character is accepted and the other rejected; the last step gives the name.
Rule 1 : Dichotomous key — Two contrasting leads at each step; one is accepted, one rejected. Keys are normally analytical.
- Easy : Wings present → go to 2; absent → go to 3.
- Medium : Choosing one lead automatically rejects its pair.
- Exam-type (CET) : Q: How many contrasting characters per step? One contrasting pair (two leads).
Rule 2 : Other taxonomic aids — Herbarium, botanical garden, museum, zoo, biodiversity park, key, flora, manual, monograph, catalogue.
- Easy : To view many organisms at a glance: museum / garden / herbarium.
- Medium : A manual gives information and keys to identify species of an area.
- Exam-type (CET) : True/false: ‘A monograph describes all plants of an area.’ False; it describes one selected group.
Dichotomous = two branches; lead = each statement in a key.
A key is not an object in a museum; it is a written/pictorial tool. Trap: do not swap definitions of flora, manual and monograph.
Memory clue : "Key = ‘two roads, take one’".
Spot the difference
| Aid | What it gives | Live / preserved |
|---|---|---|
| Herbarium | Pressed plant specimens | Preserved |
| Botanical garden | Live plants | Live |
| Key | Step-by-step identification | Written tool |
Practice questions
- 1What is a dichotomous key based on?
- 2What is a lead?
- 3What nature does a key usually have?
- 4Which of herbarium, key, catalogue holds live specimens?
- 5Into how many groups does the wings present/absent pair divide animals?
- 6What is a manual?
- 7At least how many steps are needed for a dichotomous key to separate 4 animals?
- 8What does the end of a key give?
Show answers (try them yourself first)
- 1Pairs of contrasting characters.
- 2Each statement in a key.
- 3Analytical.
- 4None; live specimens are in botanical gardens.
- 5Two groups.
- 6A tool giving identification information and keys for species of an area.
- 73 decision steps (1 + 2).
- 8The name of the identified organism.
Biodiversity and conservation
A forest with tigers, deer, grass and insects is healthy; if one group disappears, the chain breaks.
Biodiversity is the degree of variation of life forms in an ecosystem. Conservation means slowing, stopping or reversing the loss in the habitat.
In the figure : Population explosion and over-use → habitat loss → biodiversity loss → unstable ecosystem; two conservation routes below.
Rule 1 : Why biodiversity matters — It keeps an ecosystem stable; its complexity and density measure the health of the ecosystem.
- Easy : Loss of one variety can affect the entire ecosystem.
- Medium : Population explosion and over-use of resources are causing rapid loss.
- Exam-type (CET) : Q: Two main causes of loss? Population explosion and over-exploitation of resources.
Rule 2 : Kinds of conservation — In-situ = protection in the natural habitat; ex-situ = outside it (zoo, garden, museum).
- Easy : Banning shell collecting on Andaman beaches = protecting the habitat.
- Medium : Personal steps: use less plastic, plant trees, save water, segregate waste.
- Exam-type (CET) : A botanical garden is ex-situ; a national park is in-situ.
Ecosystem health is measured by the complexity and density of biodiversity.
Do not swap the names. Trap: an option saying ‘in-situ = zoo’ is wrong.
Memory clue : "In = inside the habitat, Ex = outside".
Spot the difference
| Point | In-situ | Ex-situ |
|---|---|---|
| Place | Natural habitat | Outside the habitat |
| Examples | National park, sacred grove | Zoo, botanical garden, museum |
| Benefit | Natural ecosystem is kept | Endangered species safe |
Practice questions
- 1What is biodiversity?
- 2What is in-situ conservation?
- 3Name two causes of loss.
- 4Give one in-situ and one ex-situ example.
- 5What measures the health of an ecosystem?
- 6What happens if one variety disappears?
- 7Suggest two personal steps to prevent loss.
- 8Why is a botanical garden ex-situ?
Show answers (try them yourself first)
- 1Variation of life forms in an ecosystem.
- 2Protection in the natural habitat.
- 3Population explosion, over-use.
- 4In-situ: national park; ex-situ: zoo.
- 5Complexity and density of biodiversity.
- 6The entire ecosystem can be affected.
- 7Plant trees, reduce plastic, save water (any two).
- 8Plants are grown outside their original habitat.
Scientists, history and applications of taxonomic aids
The Agharkar Research Institute in Pune carries the name of a botanist; scientists' names live on through their work.
This section covers the scientists linked with taxonomic aids, their dates, and the uses of the aids in industry, agriculture and research.
In the figure : Years are evenly spaced for reading, not drawn to scale.
Rule 1 : Luca Ghini — Italian professor (1490–1556); founded the first botanical garden at Pisa in 1543; initiated the art of herbaria.
- Easy : Pisa garden – which year? 1543.
- Medium : Word ‘herbarium’ by Pitton de Tournefort; art begun by Ghini.
- Exam-type (CET) : Kew Garden in England is famous for its huge collection of plants and herbarium sheets.
Rule 2 : Dr. S. P. Agharkar — Born in November 1884 at Malvan, Maharashtra; studied biodiversity of the Western Ghats; found a freshwater jellyfish known only from Africa, published in ‘Nature’ in 1912.
- Easy : Whose name does ARI, Pune carry? Agharkar.
- Medium : Dr. Annandale of the Indian Museum, Kolkata, helped him with collection, preservation and microscopy.
- Exam-type (CET) : Significance: finding an African species in India gave new evidence on distribution.
1543 = first botanical garden (Pisa); 1912 = Agharkar's report in ‘Nature’.
Do not swap Ghini's and Agharkar's years and work. Trap: do not memorise exact Kew numbers; remember only ‘a very large collection’.
Memory clue : "Ghini = Garden (1543); Agharkar = Africa-jellyfish (1912)".
Spot the difference
| Scientist | Time | Work |
|---|---|---|
| Luca Ghini | 1490–1556 | First botanical garden, herbarium art |
| Pitton de Tournefort | - | Coined ‘herbarium’ |
| Dr. Agharkar | 1884 - | Western Ghats study, 1912 report |
Practice questions
- 1Who founded the first botanical garden?
- 2Where and when?
- 3Where was Agharkar born?
- 4Which animal did Agharkar find?
- 5ARI Pune is named after whom?
- 6Who coined ‘herbarium’?
- 7State two uses of taxonomic aids.
- 8Sacred groves – in whose name are they conserved?
Show answers (try them yourself first)
- 1Luca Ghini.
- 2Pisa, Italy; 1543.
- 3Malvan, Maharashtra.
- 4A freshwater jellyfish (known only from Africa until then).
- 5Dr. Agharkar.
- 6Pitton de Tournefort.
- 7Data for industry and agriculture; identification and study of biodiversity.
- 8In the name of a holy place.
Quick revision of the whole lesson
| Concept | Key fact |
|---|---|
| Features of life | Metabolism, growth, ageing, reproduction, response, death |
| Herbarium | Dried specimen + label (lower right) |
| Botanical garden | Live; first: Pisa 1543 |
| Museum | Formalin and taxidermy |
| Zoo / biodiversity park | Ex-situ captive animals / self-sustaining community on barren land |
| Key | Dichotomous; leads of contrasting characters |
| Conservation | In-situ (in habitat) / Ex-situ (outside) |
| Agharkar | Malvan 1884; 1912 ‘Nature’; ARI Pune |
🎯 Most important points for the exam
- Living growth is from within; reproduction is not all-inclusive.
- Live versus preserved: herbarium, garden, museum.
- Examples of in-situ and ex-situ.
- Dichotomous key and lead.
- Ghini 1543 Pisa; Agharkar 1884 / 1912.
- Taxidermy, formalin 10–40 %, flora/manual/monograph.
Understand the concept → draw the figure → memorise the key points → solve questions yourself.