Zoology — NEET G12 Benchmarking Test-01

1 · Reproductive Health — what it means

The WHO definition — learn the four words

Reproductive health means total well-being in all aspects of reproduction — physical, emotional, behavioural and social. A society with reproductively healthy people has people with physically and functionally normal reproductive organs and normal emotional and behavioural interactions among them.

India was among the first countries in the world to initiate action plans at a national level to attain reproductive health, starting with "family planning" in 1951.
Improved programmes now cover a much wider area and are called RCH — Reproductive and Child Health Care programmes.
Major tasks: creating awareness (audio-visual and print media, government and non-government agencies), sex education in schools, and building reproductively healthy societies.
Awareness must cover: adolescence problems, safe and hygienic sexual practices, STIs, birth control options, care of pregnant mothers, post-natal care of mother and child, importance of breastfeeding, and equal opportunities for the male and the female child.
Statutory ban on amniocentesis for sex determination to check the rising female foeticide.
Better medical facilities and care to problems like menstrual irregularities, pregnancy-related issues, delivery, MTP, STIs, birth control, infertility.

Two indicators of a successful programme Massively reduced maternal and infant mortality rates, better detection and cure of STIs, and increased number of medically assisted deliveries and post-natal care — these are the yardsticks NCERT names, and the same phrases appear in the options.

Trap — amniocentesis is not the villain Amniocentesis is a foetal sex determination and disorder-detection test based on the analysis of cells in the amniotic fluid. Its legitimate use is to detect chromosomal abnormalities and metabolic disorders. What is banned is its misuse to determine the sex of the foetus and abort female foetuses — not the technique itself.

2 · Population Explosion & Birth Control

P1 · every year

The numbers

India's population: about 350 million at independence (1947) → crossed 1 billion by 2000 → about 1.2 billion by May 2011.
The population growth rate was around 1.7% (17/1000/year) — at that rate the population would double in about 33 years.
Causes: a rapid decline in maternal mortality rate (MMR) and infant mortality rate (IMR), plus an increase in the number of people in the reproducible age group. Note that the cause is not a rise in the birth rate.
Measures: raising the marriageable age — 18 years for females and 21 years for males; incentives to couples with small families.

The ideal contraceptive — six qualities

user-friendly · easily available · effective and reversible no or least side effects · should not interfere with sexual drive, desire or act

Contraceptive methods — the full classification

Category	Methods	How it works / key points
Natural / Traditional	Periodic abstinence, withdrawal (coitus interruptus), lactational amenorrhoea	Avoids meeting of ovum and sperm. Periodic abstinence — no coitus from day 10 to 17 of the cycle (the fertile period). Lactational amenorrhoea works only up to six months after delivery and only with full breastfeeding. No side effects, but high chance of failure.
Barrier	Condoms (Nirodh), diaphragms, cervical caps, vaults	Physically prevent the ovum and sperm from meeting. Condoms are disposable, can be self-inserted, give privacy, and also protect against STIs and AIDS — the only method that does both.
IUDs (intra-uterine devices)	Non-medicated: Lippes loop Copper-releasing: CuT, Cu7, Multiload 375 Hormone-releasing: Progestasert, LNG-20	Inserted by a doctor or nurse. Increase phagocytosis of sperms in the uterus; Cu ions suppress sperm motility and fertilising capacity; hormone-releasing IUDs make the uterus unsuitable for implantation and the cervix hostile to sperms. Ideal for females who want to delay or space pregnancies.
Oral contraceptives	Pills of progestogens or progestogen–oestrogen combinations; Saheli	Taken daily for 21 days starting within the first five days of the cycle, then a 7-day gap. They inhibit ovulation and implantation and alter the cervical mucus to retard sperm entry. Saheli is a non-steroidal, once-a-week pill with very few side effects and high contraceptive value — developed by CDRI, Lucknow.
Injections / implants	Progestogens alone or with oestrogen	Same mechanism as pills but a longer period of action.
Emergency contraception	Progestogens or progestogen–oestrogen combinations, or IUDs	Effective if used within 72 hours of coitus — useful after rape or unprotected intercourse.
Surgical (sterilisation)	Vasectomy (male) — vas deferens cut and tied Tubectomy (female) — fallopian tube cut and tied	Block gamete transport. Highly effective but reversal is very poor — these are terminal methods.

Trap — match the method to its mechanism

Copper IUD → suppresses sperm motility and fertilising capacity (not ovulation)
Oral pill → inhibits ovulation and implantation, alters cervical mucus
Vasectomy → vas deferens; Tubectomy → fallopian tube. Do not swap these.
Only condoms protect against STIs; no other method does.
Saheli is non-steroidal and weekly — steroidal and daily are both wrong.

Only the barrier branch does double duty — contraception and STI protection.

3 · MTP and Sexually Transmitted Infections

Medical Termination of Pregnancy (MTP) / induced abortion

Government of India legalised MTP in 1971 with strict conditions to check its misuse.
Nearly 45–50 million MTPs are performed a year worldwide — about one fifth of all pregnancies.
Safe during the first trimester (up to 12 weeks); second-trimester abortions are much riskier.
Legitimate uses: getting rid of unwanted pregnancies (casual unprotected intercourse, failure of contraceptive, rape), and cases where continuation could be harmful or fatal to the mother, the foetus, or both.
Misuse: illegal female foeticide after sex determination — a major social problem.

STIs — the list and the exceptions

Infection	Curable?
Gonorrhoea, syphilis, chlamydiasis, trichomoniasis	Curable if detected early and treated properly
Genital warts	treatable
Genital herpes, hepatitis-B, HIV infection	Not curable — memorise these three

Also called venereal diseases (VD) or reproductive tract infections (RTI).
Except for hepatitis-B, HIV and genital herpes, all the others are completely curable if detected early.
Early symptoms: itching, fluid discharge, slight pain, swelling in the genital region — often absent or very mild in females, so cases go undetected.
Complications if untreated: pelvic inflammatory disease (PID), abortions, stillbirths, ectopic pregnancies, infertility, and even cancer of the reproductive tract.
Most vulnerable group: 15–24 years of age.
Hepatitis-B and HIV are also transmitted by sharing injection needles, surgical instruments, transfusion of blood, and from an infected mother to the foetus.

Prevention — the three rules

Avoid sex with unknown or multiple partners.
Always use condoms during coitus.
In case of doubt, go to a qualified doctor for early detection and get complete treatment if diagnosed.

4 · Infertility and Assisted Reproductive Technologies

P1 · high yield

Infertility = inability to produce children in spite of unprotected sexual cohabitation. Causes may be physical, congenital, disease-related, drug-related, immunological or psychological, and the male may be the reason as often as the female — a point NCERT stresses because of the social tendency to blame the woman.

Technique	Full form	What exactly is transferred, and where
IVF–ET	In vitro fertilisation followed by embryo transfer ("test tube baby" programme)	Ova and sperms are collected and fertilised in the laboratory. The zygote or early embryo up to the 8-blastomere stage is transferred into the fallopian tube (ZIFT); embryos with more than 8 blastomeres are transferred into the uterus (IUT) to complete development.
ZIFT	Zygote Intra Fallopian Transfer	Zygote or early embryo (up to 8 blastomeres) → fallopian tube
IUT	Intra Uterine Transfer	Embryo with more than 8 blastomeres → uterus
GIFT	Gamete Intra Fallopian Transfer	An ovum collected from a donor is transferred into the fallopian tube of another female who cannot produce an ovum but can provide a suitable environment for fertilisation and further development.
ICSI	Intra Cytoplasmic Sperm Injection	A single sperm is injected directly into the ovum in the laboratory to form an embryo. Used when the sperm count is very low.
AI / IUI	Artificial Insemination / Intra Uterine Insemination	Semen collected from the husband or a healthy donor is introduced into the vagina or into the uterus (IUI). Used when the male has a very low sperm count or is unable to inseminate.

Trap — ZIFT vs GIFT vs IUT ZIFT moves a zygote in; GIFT moves a gamete (ovum) in. The letter Z is for zygote and the letter G is for gamete — the destination is the fallopian tube in both. IUT is the one that goes to the uterus, and it takes embryos with more than 8 blastomeres. The "8 blastomere" number is the switch between ZIFT and IUT and is asked directly.

The social note NCERT ends on Emotional, religious and social factors deter couples from accepting ART. Legal adoption is one of the best ways for couples looking for parenthood, given the number of orphaned and destitute children in India.

5 · Origin of Life

The timeline

Big Bang — about 20 billion years ago. The universe expanded, temperature came down, hydrogen and helium formed, and gases condensed under gravitation to form galaxies.
Earth formed about 4.5 billion years ago. There was no atmosphere in the early Earth.
Water vapour, methane, carbon dioxide and ammonia released from molten mass covered the surface. UV rays split water into hydrogen and oxygen; the lighter hydrogen escaped, oxygen combined with ammonia and methane. Ozone formed a layer.
The cooling atmosphere let water vapour fall as rain and fill the depressions — the oceans.
Life appeared about 3.5 billion years ago, in water.

Theory	Claim	Status
Theory of special creation	All living things were created by a divine agency; the number and kinds have not changed since.	Not scientific
Panspermia (cosmozoic)	Spores or "units of life" travelled to Earth from outer space.	Favoured by some early Greek thinkers; not accepted as an explanation of origin, only of arrival
Spontaneous generation (abiogenesis)	Life came out of decaying and rotting matter — straw, mud, etc.	Disproved by Louis Pasteur with his swan-necked flask experiment: life came only from pre-existing life in flasks open to air, and no life appeared in the killed yeast flask that was sealed.
Oparin and Haldane — chemical evolution	The first form of life arose slowly from non-living organic molecules such as RNA, protein etc. Conditions on early Earth were reducing, with high temperature, volcanic storms, and CH₄, NH₃ etc.	The accepted modern view

The Miller–Urey experiment (1953) — the details that get asked

S. L. Miller, an American scientist, created similar conditions in a laboratory scale.
He created electric discharge in a closed flask containing CH₄ (methane), H₂ (hydrogen), NH₃ (ammonia) and water vapour at 800 °C.
He observed the formation of amino acids.
In similar experiments others observed the formation of sugars, nitrogen bases, pigments and fats.
Analysis of meteorite content also revealed similar compounds, indicating that molecular evolution took place elsewhere in space too.

The experiment supported chemical evolution — it did not create life, only its building blocks.

Trap — what Miller actually used CH₄, H₂, NH₃ and water vapour at 800 °C with electric discharge. Oxygen was absent — the early atmosphere was reducing. Any option containing O₂ or CO₂ as an input gas is wrong.

6 · Evidences for Evolution

Evidence	Meaning	Examples
Palaeontological (fossils)	Remains of hard parts of life forms found in rocks. Different-aged rock sediments contain different life forms, some of which appear similar to existing organisms. Study of the age of the rocks gives the geological time scale.	Archaeopteryx — a fossil with features of both reptiles and birds, the connecting link. Dinosaur fossils.
Comparative anatomy — homology	Same fundamental structure, different functions → common ancestry → divergent evolution	Forelimbs of whale, bat, cheetah and human share humerus, radius, ulna, carpals, metacarpals and phalanges. Hearts and brains of vertebrates. In plants: thorn of Bougainvillea and tendril of Cucurbita.
Comparative anatomy — analogy	Different structure, same function → no common ancestry → convergent evolution	Wings of butterfly and bird; eye of octopus and mammal; flippers of penguins and dolphins; sweet potato (root modification) and potato (stem modification).
Biochemical / molecular	Similarities in proteins and genes performing a given function among diverse organisms	Same DNA, same genetic code, similar enzymes — evidence of common ancestry at the molecular level.
Artificial selection	Man has bred many varieties from wild ancestors over a few centuries, showing how selection changes populations	All modern breeds of dog from the wolf; many vegetables from wild cabbage.
Evolution by anthropogenic action	Selection observed within a human lifetime	Industrial melanism in Biston betularia; resistance to antibiotics and pesticides; herbicide-resistant weeds.

Industrial melanism — the exact story

Before industrialisation (1850s) in England: more white-winged moths than dark-winged ones on trees, because tree trunks were covered with white lichen and the white moths were camouflaged.
After industrialisation (1920): more dark-winged moths, because soot killed the lichens and the trunks turned dark — now the white moths stood out and were picked off by predators.
The moth is Biston betularia (peppered moth). No variant is completely wiped out — the frequencies change, the alleles remain in the population.
In unpolluted areas the white-winged moths still outnumbered the dark ones — a natural control.

Adaptive radiation

Adaptive radiation = the process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography (habitats).

Darwin's finches of the Galapagos Islands — from an original seed-eating stock, many varieties arose with altered beaks enabling them to become insectivorous and vegetarian finches.
Australian marsupials — a number of marsupials, each different from the other, evolved from an ancestral stock within the Australian island continent.
Placental mammals in Australia also show adaptive radiation: when more than one adaptive radiation appears to have occurred in an isolated geographical area representing different habitats, this is called convergent evolution. Placental wolf and Tasmanian wolf (marsupial) are the standard pair.

7 · Homologous or Analogous? — tap to check

Fix this tonight

The one-line rule Homologous = same structure, different function → divergent evolution → common ancestor.
Analogous = different structure, same function → convergent evolution → no common ancestor.
Ask yourself which one is "same": if the anatomy is the same it is homologous; if only the job is the same it is analogous.

Twelve pairs — decide first, then tap to reveal

Aamirah, this distinction has cost you marks before. Go through all twelve and only tap after you have committed to an answer in your head.

Tapped 0 of 12.

The bones are identical in plan and sequence — only their proportions were reshaped by different lifestyles.

8 · Lamarck and Darwin

	Lamarck	Darwin
Central idea	Use and disuse of organs and the inheritance of acquired characters	Natural selection and branching descent
Standard example	Giraffes stretched their necks to reach leaves on tall trees, and passed the longer neck to their offspring	Individuals vary; those with favourable variations leave more progeny; over generations the population changes
Status	Rejected — acquired characters are not inherited (somatic changes do not enter the germ line)	Accepted, and strengthened by genetics
Key work	—	On the Origin of Species, 1859

Darwin's observations and the voyage

Darwin sailed around the world in the HMS Beagle and observed the Galapagos Islands finches.
Alfred Russel Wallace, working in the Malay Archipelago, arrived at the same conclusion independently — the two ideas were presented together.
Key concepts: variation is inherited; there is a fitness difference (better adapted individuals survive and reproduce more); fitness means reproductive fitness — surviving is only useful if it produces more offspring. Herbert Spencer's phrase "survival of the fittest" is used for this.
Darwin was influenced by Thomas Malthus's work on populations.
Nature selects for fitness — nature, not the organism, does the selecting.

Trap — Lamarck's giraffe vs Darwin's giraffe Lamarck: the neck became longer during the animal's life and that acquired length was passed on. Darwin: giraffes with naturally longer necks already existed, and they survived better and left more offspring. The variation comes first in Darwin's account — that is the whole difference.

9 · Hardy–Weinberg Principle — live calculator

P1 · numerical

p + q = 1 · p² + 2pq + q² = 1 p² = frequency of AA · 2pq = frequency of Aa · q² = frequency of aa The principle states that allele frequencies in a population are stable and constant from generation to generation — the gene pool remains a constant. This is called genetic equilibrium, and the sum total of all allelic frequencies is 1.

Change one allele frequency and watch the genotypes

A recessive disorder shows up in only q² of the population — but carriers (2pq) are far more common. Slide q down and notice how slowly the carriers disappear.

Recessive allele frequency q 0.30

p (dominant)

—

AA = p²

—

Aa = 2pq

—

aa = q²

—

Carriers : affected

—

The five factors that disturb the equilibrium

Factor	Effect
Gene migration (gene flow)	Movement of individuals between populations changes allele frequencies in both — the donor and the recipient. If it happens repeatedly it is called gene flow.
Genetic drift	Change by chance, important in small populations. If the change is large enough, the new population becomes a different species. The original drifted population becomes the founders — the founder effect.
Mutation	Creates new alleles; large single-step mutations can cause saltation.
Genetic recombination	Reshuffles existing alleles during meiosis.
Natural selection	Non-random survival and reproduction — the only one of the five that is directional and adaptive.

Trap — the assumptions Hardy–Weinberg equilibrium holds only when there is no mutation, no migration, no genetic drift, no selection, random mating and a very large population. A question saying "a population is in Hardy–Weinberg equilibrium" is telling you that none of these five forces is acting.

10 · Types of Natural Selection & Speciation

Dashed grey = the original population; green = after selection.

Other terms in the chapter

Divergent evolution — one ancestral stock gives rise to many differing forms (homologous organs).
Convergent evolution — unrelated organisms come to resemble each other because they face the same environmental challenge (analogous organs).
Saltation — single-step large mutation, proposed by Hugo de Vries from his work on Oenothera lamarckiana (evening primrose). De Vries believed evolution was mutation-driven and occurred in large jumps, unlike Darwin's slow, minor, directional variations.
De Vries used the term mutation for these large, sudden, random and directionless changes.

The geological sweep — evolution of life forms in order

First cellular forms in water (~3.5 bya) → single-celled organisms → invertebrates → jawless fish → fish with stout fins that could move on land (~350 mya) → amphibians → reptiles (laid thick-shelled eggs that did not dry in the sun) → giant reptiles/dinosaurs dominated ~200 mya and disappeared suddenly about 65 mya → mammals and birds radiated.

Coelacanth — a fish caught in South Africa, thought extinct, related to the lobefins that gave rise to the first amphibians.
Mammals were viviparous and protected their young — a decisive advantage.
Seed-bearing ferns, gymnosperms and then angiosperms mark the plant sequence.

11 · Human Evolution

P1 · direct recall

Cranial capacity is the number NEET asks for — 650–800 → 900 → 1400 cc.

Form	When / where	Cranial capacity	Key point
Dryopithecus	~15 mya	—	More ape-like; hairy; walked like gorillas and chimpanzees
Ramapithecus	~15 mya	—	More man-like; walked erect
Australopithecus	2 mya, East African grasslands; fossils 3.5 mya in Ethiopia and Tanzania	—	Lived in trees and on the ground; hunted with stone weapons but essentially ate fruit
Homo habilis	~2 mya	650–800 cc	The first human-like being; probably did not eat meat
Homo erectus	~1.5 mya, fossils in Java (1891)	~900 cc	Probably ate meat
Neanderthal man	1 lakh–40 000 years ago, East and Central Asia	1400 cc	Used hides to protect the body and buried their dead
Homo sapiens	Arose in Africa, moved across continents 75 000–10 000 years ago	~1350 cc	Agriculture ~10 000 years ago; human settlements began

Trap — the two "ate meat" statements Homo habilis probably did NOT eat meat. Homo erectus probably DID. Australopithecus hunted with stone weapons but essentially ate fruit. These three sentences are lifted almost word for word into options with one word changed. Also note that the largest cranial capacity in the table belongs to the Neanderthal (1400 cc), not to modern humans — a favourite catch.

60-Second Recall — read this in the car

Family planningIndia, 1951 · now RCH

Marriageable agefemale 18 · male 21

Population1947 350 M → 2000 1 bn → 2011 1.2 bn

Fertile-period abstinenceday 10–17 of the cycle

Lactational amenorrhoeaworks up to 6 months

Copper IUDsuppresses sperm motility

Sahelinon-steroidal, once a week

Emergency contraceptionwithin 72 hours

Sterilisationvasectomy = vas deferens · tubectomy = fallopian tube

MTPlegal 1971 · safe up to 12 weeks

Incurable STIsgenital herpes, hepatitis-B, HIV

STI risk group15–24 years

ZIFT vs IUT≤8 blastomeres → tube · >8 → uterus

GIFTdonor ovum → fallopian tube

ICSIone sperm injected into ovum

Big Bang / Earth / life20 bn · 4.5 bn · 3.5 bn years

Miller–UreyCH₄, H₂, NH₃, H₂O vapour, 800 °C

Abiogenesis disproved byLouis Pasteur

Homologoussame structure → divergent

Analogoussame function → convergent

Connecting linkArchaeopteryx — reptile + bird

Industrial melanismBiston betularia

Adaptive radiationDarwin's finches · Australian marsupials

Hardy–Weinbergp² + 2pq + q² = 1

Five disturbing factorsmigration, drift, mutation, recombination, selection

Saltationde Vries · Oenothera

Cranial capacityhabilis 650–800 · erectus 900 · Neanderthal 1400

Homo sapiens originAfrica · agriculture 10 000 yr ago