"Bhai, New NCERT me sirf Frog diya hai. Lekin coaching wale bol rahe hain Cockroach bhi aayega aur Earthworm bhi padh lo safe side ke liye. 3 alag organisms padhne me 15 din nikal jayenge!"
Every NEET dropper faces this exact dilemma in September when coaching institutes start Structural Organisation in Animals.
One teacher prints 40 pages of Cockroach notes. Another says: "Only Frog is given in NCERT, don't waste time on anything else." A third teacher assigns 50 questions on Earthworm's typhlosole and chloragogen cells.
Who is telling the truth?
Here is the exact official reality from the National Medical Commission (NMC) syllabus and New NCERT curriculum, along with what you must study and what you must completely ignore.
Seedha Faisla: Frog vs Cockroach Ka Asli Faisla 🐸
The Official Ruling on Animal Morphology for NEET 2027:
- Frog (Rana tigrina): 100% COMPULSORY. Frog is printed in full detail in the Rationalized New NCERT (Unit 2). Expect 1 to 2 direct questions from Frog anatomy, circulation, or reproduction.
- Cockroach (Periplaneta americana): SELECTIVE HIGH-YIELD. While removed from the rationalized NCERT textbook, NMC retained the phrase "and an insect (Cockroach)" in the official syllabus document. Prepare only the 4 high-yield functional systems (digestive, respiratory, excretory, and reproductive).
- Earthworm (Pheretima posthuma): 100% DEAD. Earthworm is absent from both the New NCERT and the NMC syllabus. Do not waste even 10 minutes on Earthworm.
The 3 Organisms Compared: Study Time vs Exam Probability
Before you spend three days highlighting animal tissue diagrams, look at this honest assessment:
| Organism | NCERT Status | NMC Official Syllabus Status | Exam Probability | Required Study Time | Your Action |
|---|---|---|---|---|---|
| Frog (Rana tigrina) | Included in New NCERT (Unit 2, Ch 7) | Explicitly Listed | 100% (High) | 3.5 Hours | Master line-by-line from New NCERT |
| Cockroach (Periplaneta) | Excluded from New NCERT | Listed as "an insect (Cockroach)" | 40-50% (Moderate) | 1.5 Hours | Study 4 high-yield structures only |
| Earthworm (Pheretima) | Excluded from New NCERT | Completely Removed | 0% (Zero) | 0 Minutes | Skip completely. Do not touch |
Part 1: Frog Mastery (The Must-Score Core)
Because Frog is printed directly in the New NCERT textbook, NTA frames high-difficulty assertion-reason and statement-based questions straight from its lines.
Here are the 5 high-yield systems you must know inside out:
┌────────────────────────────────────────────────────────────────────────┐
│ FROG HIGH-YIELD ZONES │
├───────────────────┬────────────────────────────────────────────────────┤
│ Circulatory │ 3-chambered heart (2 atria, 1 ventricle) │
│ │ Sinus venosus (opens to right atrium) │
│ │ Conus arteriosus (leaves ventricle ventrally) │
│ │ Hepatic portal & Renal portal systems present │
├───────────────────┼────────────────────────────────────────────────────┤
│ Excretory/Urogenital│ Ureotelic, Mesonephric kidneys │
│ │ Male: 10-12 vasa efferentia enter Bidder's canal │
│ │ Bidder's canal communicates with ureter (urogenital)│
│ │ Female: Oviduct opens separately into cloaca │
├───────────────────┼────────────────────────────────────────────────────┤
│ Sensory / Nervous │ 10 pairs of cranial nerves │
│ │ Tympanum with single ear ossicle (columella auris) │
│ │ Nictitating membrane protects eye in water │
├───────────────────┼────────────────────────────────────────────────────┤
│ External Sex Diffs│ Male has vocal sacs & copulatory pad on 1st digit │
└───────────────────┴────────────────────────────────────────────────────┘The 3 Biggest Frog Traps:
- The Urogenital Duct Trap: In male frogs, the ureters act as a urogenital duct (carrying both urine and sperms from Bidder's canal) and open into the cloaca. In female frogs, the ureters and oviducts open separately into the cloaca; ureters carry only urine!
- The Portal System Trap: Frogs have BOTH a Hepatic portal system (connection between gut and liver) and a Renal portal system (connection between lower body/limbs and kidneys). Humans do NOT have a renal portal system.
- Respiration Types: In water, frog breathes only through skin (Cutaneous respiration, dissolved $O_2$ by diffusion). On land, it uses skin, buccal cavity (Buccopharyngeal), and lungs (Pulmonary). During aestivation (summer sleep) and hibernation (winter sleep), it breathes exclusively through skin.
Part 2: Cockroach (The 4 High-Yield Structures)
Do not read a 40-page module on Cockroach. If NTA asks a question on Cockroach under the NMC insect clause, 95% of past questions come from these 4 specific anatomical spots:
1. The Alimentary Canal (Foregut & Midgut Junctions)
- Crop: Large thin-walled sac used for storing food.
- Gizzard / Proventriculus: Muscular structure with thick circular muscles and 6 chitinous teeth that grind food particles.
- Hepatic Caeca / Gastric Caeca: A ring of 6 to 8 blind tubules present at the junction of foregut and midgut. They secrete digestive juices.
2. The Excretory System & Malpighian Tubules
- Malpighian Tubules: A ring of 100 to 150 yellow-colored, thin filamentous tubules present at the junction of midgut and hindgut.
- They absorb nitrogenous waste from hemolymph and convert it into potassium urate / uric acid (Cockroach is uricotelic).
- Additional excretory structures to remember: Fat body, Nephrocytes, and Urecose glands.
3. Vision & Compound Eyes
- Cockroaches possess a pair of large compound eyes on the dorsal surface of the head.
- Each eye consists of about 2,000 hexagonal ommatidia.
- With multiple ommatidia, a cockroach receives several images of an object. This is called mosaic vision — characterized by high sensitivity but low resolution, ideal for nocturnal vision.
4. Reproductive Structures (Male vs Female)
- Male:
- Testes located in the 4th to 6th abdominal segments.
- Mushroom-shaped gland (utricular gland) present in the 6th to 7th abdominal segments, acting as an accessory reproductive gland.
- External genitalia represented by male gonapophyses or phallomeres (asymmetrical chitinous structures).
- Sperms are glued together in bundles called spermatophores.
- Female:
- Ovaries located laterally in segments 2 to 6. Each ovary made of 8 ovarian tubules (ovarioles).
- Pair of spermathecae present in the 6th segment, opening into genital chamber.
- Eggs encased in dark reddish-brown capsules called oothecae (approx. 9-10 oothecae produced, each holding 14-16 eggs).
Part 3: Why Earthworm Must Be Skipped
If your coaching teacher is still dictating notes on Earthworm's blood glands in segments 4, 5, and 6, or spermathecal pores in intersegmental grooves 5/6 to 8/9: politely close that notebook.
Here is why:
- Earthworm was completely struck from NCERT during the rationalization.
- The NMC syllabus mentions "Frog and an insect (Cockroach)". There is zero mention of annelids or earthworms.
- Spending 4-5 study hours on Earthworm means taking 5 hours away from Genetics, Chemical Bonding, or Ray Optics. As we outlined in our NEET 2027 Rationalized Syllabus Guide, your drop year cannot afford time spent on dead topics.
The 4-Hour Revision Schedule for Unit 2
Use this quick timetable to finish the entire animal morphology section:
┌────────────────────────────────────────────────────────────────────────┐
│ ANIMAL MORPHOLOGY SPEED PLAN (4 HOURS TOTAL) │
├───────────────────┬────────────────────────────────────────────────────┤
│ Hour 1 & 2 │ Read Frog line-by-line from New NCERT. Draw │
│ │ digestive, vascular, and urogenital diagrams. │
│ Hour 3 │ Review the 4 Cockroach structures (Crop, Gizzard, │
│ │ Malpighian tubules, Ommatidia, Mushroom gland). │
│ Hour 4 │ Solve 40 PYQs (25 on Frog, 15 on Cockroach). │
│ │ Log missed traps in Learnzy Mistake Notebook. │
└───────────────────┴────────────────────────────────────────────────────┘When solving questions, keep an eye out for terms like cloacal aperture, Bidder's canal, and sinus venosus. If you make mistakes on assertion-reason questions, tag them in your Learnzy Mistake Notebook so you can review them before your next minor test.
Frequently Asked Questions
Q1: Is Cockroach mentioned in the New NCERT at all?
The New NCERT textbook does not contain the dedicated Cockroach anatomy section. However, because the NMC syllabus document explicitly kept the phrase "and an insect (Cockroach)", coaching test series and NTA Section B may draw 1 question on classic organ systems. That is why learning the 4 high-yield spots is your safest, highest-ROI strategy.
Q2: Can NTA ask questions from Earthworm in Section B?
No. Earthworm is not in the NCERT and not in the NMC syllabus. In NEET 2024 and 2025, zero questions were asked on Earthworm. Any coaching test that includes Earthworm is simply reusing old question banks from 2020. Read our guide on Why Coaching Mocks Have Deleted Syllabus Questions for the full explanation.
Q3: What is the most common mistake students make in Frog?
Confusing the male and female urogenital system. In males, the ureter passes through Bidder's canal to carry both urine and semen (urogenital duct). In females, the ureter carries only urine, and the oviduct opens into the cloaca separately.