REPRODUCTION, LOCOMOTION, BIODIVERSITY AND CONSERVATION, BIOLOGY IN
HUMAN WELFARE
REPRODUCTION
1. Reproduction is the process by which an individual multiplies by producing many individuals
of same kind. Reproduction may be Asexual or Sexual. In asexual reproduction, gametes are
not formed. It may be Fission , Sporulation, Budding etc. Fission is the division of the parent
body into two or many pieces and each piece develop into an organism. Fission may be Binary
fission (Amoeba, Paramecium Planaria etc ) or Multiple fission ( Plasmodium ). Sporulation is
the division of the nucleus into many pieces and formation of many individuals. Budding is
the formation of an individual from the parent body ( Hydra ). Sexual reproduction involves
formation of gametes, fusion of gametes and development of zygote.
2. Seminiferous tubules are the functional units of the testis from which sperms are formed.
Primordial germ cells of seminiferous tubules produce sperms, Leydig cells secrete androgens
( Testosterone ), and Sertoli cells or nurse cells nourish sperms. Sertoli cells also secrete a
hormone Inhibin to inhibit the secretion of FSH. Rete testis is the network of tubules
connection the seminiferous tubules in the central region of testis.
3. Secretion of the Prostrate gland makes the sperms active. The secretion of prostrate gland
contains calcium ions, phosphate ions and an enzyme Prpfibrinolysin. Cowpers gland secrete
a clear lubricating fluid. Normal pH of seminal fluid is 7.35 to 7.5.
4. Eggs develop in the Graffian follicles of ovary. Graffian follicles also secrete homones.
Naturally occurring oestrogens are Estrone, 17b estradiol and Estriol. Estradiolis the potent
female hormone. Corpus luteum is the ruptured graffian follicle. It secretes Progesterone.
Corpus albicans or Yellow body is the degenerating corpus luteum.
5. Fallopian tube is the site of fertilization. Unusual development of egg in the fallopian tube is
called Ectopic pregnancy. Endometrium is the inner vascularised lining of uterus in which
implantation takes place.
6. Zona pellucida is the non cellular covering of the egg. It is covered with follicle cells which
form the Corona radiata.
7. Menarche is the starting of menstrual cycle and Menopause is the stopping of menstrual cycle
8. Parthenogenesis is the development of egg without fertilization. It may be Arrhenotoky ( only
males are formed – Honey bee ), Thelytoky ( only females are formed – Gall fly ) and
Amphitoky ( both male and females are formed – Aphids ).
9. Secretion of Seminal vesicle contains Prostaglandins which causes contraction of smooth
muscles of uterus. Fructose present in the seminal fluid is the source of energy for the sperm.
10. Based on the amount of yolk egg may be Alecital ( without yolk – Mammalian egg ),
Microlecithal ( little yolk – Amphibian egg ) Megalecithal etc ( large amount of yolk – Bird’s
egg ). Cledoic eggs are shelled eggs ( Birds, Reptiles ).
11. Fertilizin is a glycoprotein present on the egg. Antifertilizin ( formed of acidic aminoacids ) is
present on the sperm head. Capacitation is the preparation of sperms for fertilization. It starts
from Acrosomal reaction. Hyaluronidase and Neuraminidase are the hydrolytic enzymes
present in the acrosome of sperm.
12. Artificial insemination refers to the artificial transfer of sperms into the female’s body.
Surrogate mother carries fertilized egg of another female in her uterus. Oral contraceptives are
birth controlling pills. These are synthetic estrogens and progesterons. Copper T is an Intrauterine device ( IUD ) that release copper ions in the uterus to prevent implantation.
13. Holoblastic cleavage is the complete division of Zygote ( Human egg ) and Meroblastic
cleavage is the partial division ( Insects, Reptiles ). Spiral cleavage is seen in nematodes,
rotifers, annelida and mollusca.
14. Morula is the 32 celled stage formed after cleavage. Blastula with a cavity is called as
Coeloblastula ( Frog ) and solid blastula is called Stereoblastula ( Neries ).
15. Fate map was developed by Vogt in 1925. It shows the fate of various germ layers.
16. Foetal membranes or Extra embryonic membranes are Amnion ( protection ) Chorion
( protection, nourishment and excretion ), Allantois ( respiration, excretion ) and Yolk sac
( storage of yolk ). Human placenta is Haemochorial , Deciduous and Meta discoidal.
LOCOMOTION
1. In Hydra locomotion is effected through Climbing, Looping, Somersalting and Floating.
Myoepithelial cells in the body wall of hydra helps in locomotion.
2. Haversian canal is the central canal of the Haversian system of bones. Volkman’s canals are
the transverse canals of the Haversian system.
3. Spongy bones are present in the deeper central parts of long bones. It contains red bone
marrow,and interconnecting plates ( Trabaculae ). Compact bones has Haversian system and
contains Yellow bone marrow.
4. Chondroblasts are cartilage cells which are not enclosed in lacunae and Chondrocytes are
cartilage cells enclosed in lacunae. Perichondrium is the connective tissue covering of
cartilage. Cartilage may be Hyaline cartilage (ends of ear bones, joints, nasal septum tracheal
rings etc.), White fibrous cartilage (between vertebrae, knee, pubic bones ) and Elastic
cartilage(ear pinna, larynx, Eustachian tube, epiglottis etc.)
5. Human skeleton has 206 bones. Axial skeleton (skull and vertebral column) contains 80 bones
and Appendicular skeleton 126 bones. Skull has 29 bones. There are 33 vertebrae in the
vertebral column. These are Cervical (7), Thoracic (12), Lumbar (5), Sacral (5) and Coccyx (4).
6. There are 12 pairs of Ribs. First seven pairs are True ribs which are connected to the sternum.
8th, 9th and 10th pairs are False ribs which are attached each other and to the 7th pair. 11th and
12th pairs are called Floating ribs which are not connected to the sternum and remains free.
7. Glenoid cavity is meant for the articulation of Humerus with the pectoral girdle and
Acetabulum articulates Femur with the pelvic girdle. Patella forms the knee cap.
8. There are different types of joints. These are Fixed joints ( Sutures of skull, articulation of
teeth), Slightly movable joints are also called Cartilage joints (Vertebrae), Movable joints or
Synovial joints ( articulating ends of bones), Ball and socket (Shoulder, Hip), Hinge
joints(Elbow, Phalanges), Pivot joint ( Skull and Vertebral column), Gliding joint ( Wrist,
Angle), Ellipsoid joint ( Phalanges).
9. Rheumatoid arthritis is the inflammation of Synovial membrane and Osteo arthritis is a
degenerative joint disease. Osteoporosis is the condition in which there is decreased amount of
bone marrow. This is due to prolonged use of Cortisone, imbalance of Thyrocalcitonin,
deficiency of Vit. D , Calcium etc.
10. Dark band of muscle is called Anisotropic or A band. Light band is Isotropic band or I band. H
zone or Hensen’s zone lies in the middle part of the A band. M line is the dark line passing
through the H zone.
11. Actin is thin and found in I band. Myosin is thick and found only in A band. Width of A band
is equal to the length of Myosin. Tropomyosin protein is present along the groove of actin
double helix. Myosin has a head and tail. Head is formed of Heavy Mero Myosin (HMM)
which shows the contractile property , ATPase activity and form cross bridge with actin. Tail
is formed of Light Mer Myosin (LMM).
12. Sliding filament theory of muscle contraction was proposed by H.Huxley and Hanson,
A.P.Huxley and Neidergerke in 1954.
13. Red muscle contains large amount of mitochondria and myoglobin. It shows aerobic activity
and low rate of fatigue Eg. Extensor muscle of back that keeps posture. White muscle has less
mitochondria and myoglobin. It is meant for fast work for a short period. Eg. Muscles of eye
ball.
14. Stapedius is the smallest muscle and Gluteus maximus is the largest muscle. Sartorius muscle
of thigh is the longest muscle and Masseter muscle of jaw is the strongest muscle. Intercostal
muscles are present between the ribs. Ligament connects bones at the joints and Tendon
connects muscles with bones. Tetanus is the sustained contraction of muscle . Oxygen debt
refers to the deficiency of Oxygen in the muscle.
BIODIVERSITY AND CONSERVATION
1. Biodiversity is the totality of genes, species and ecosystems of a region. The levels of
biodiversity are genetic diversity, species diversity, community diversity and ecosystem
diversity. Alpha diversity refers to the diversity of organisms sharing the same community
or habitat. Beta diversity is the replacement of species along a gradient of habitats and
communities. Gamma diversity is the diversity of habitats over the total landscape or
geographical area.
2. Endangered species is the species that is facing extinction in the near future. Egs. Asiatic
wild ass, Great Indian bustard, Black buck, Asiatic lion, Musk deer, Lion tailed monkeyetc.
Rare species include small populations that are not endangered at present but at risk of
extinction. Egs. Snow loris, Indian desert cat, Wild Yalk, Himalayan newt.
3. Insitu conservation is the preservation of genetic resources in the natural habitats. Excitu
conservation is the conservation of species outside its habitat.
4. Man and Biosphere Programme ( MAB ) was launched by UNESCO in 1975 to conserve
nature. Red data is the catalogue of animals and plants that are at the verge of extinction.
Hot spots are the reservoirs of many threatened species of animals and plants. The concept
of Hot spot was developed by Norman Myers in 1988. The Hotspots of India are Western
Ghats and Eastern Himalayas.
5. Sundarban national park of West Bengal is a Tiger reserve. The only Butterfly park in India
is located in Gangtok ( Assam). 5th June is celebrated as World Environment day.
BIOLOGY IN HUMAN WELFARE
1. Natality refers to the birthrate and Mortality death rate. Vital index is the ration between
birth rate and death rate. Environmental resistance refers to the sum total of
environmental factors that check over multiplication of organisms.
2. Hypochondriasis is a Psychosomatic disorder that develops in adolescence due to anxiety.
Neurasthenia refers to lack of concentration and depression.
3. Sigmoid curve or S- curve shows the population growth rate. It is obtained by plotting the
number of animals against time. J- curve is the Exponential curve also shows population
growth rate. It has only lag phase and exponential phase.
4. Amniocentesis is a prenatal technique used to detect chromosome abnormalities in
developing foetus. It is done by examining the cells of the Amniotic fluid. Chorionic Villi
Sampling ( CVS) is another prenatal diagnosis.
5. Sedatives and Tranquillisers are drugs that inhibits brain activities. Egs. Barbiturates,
Valium ( Benzodiazephines). Opiatic narcotics are used as pin killers and includes
Morphine, Codeine, Heroin, Pethidine etc. Opiate drugs are obtained from the Opium
plant ( Papaver somniferum ). Amphitamines and Cocaines are stimulants causing
excitements by stimulating brain. Hallucinogens alter the person’s feelings and thoughts
by producing hallucinations. Egs. LSD, Mescaline, Charas, Ganga etc.
6. Teratogens are agents that cause abnormalities in developing foetus leading to birth
defects. Alcohol, Heroin, Cocaine. A recently banned pesticide Endosulfan also act as
teratogen.
7. Autografting is the transfer of tissues or organ from one place of the body to another place
in the same individual. Allografting is the transfer of tissues from one individual to
another genetically different individual. Xenograft is the tissue transferred from one
individual to another of a different species. Immunosuppressive drugs prevents tissue
rejection by reducing the immune response after organ transplantation .