Life Processes in Animals

Animals ko energy aur growth ke liye food ki zaroorat hoti hai. Ye food complex substances se bana hota hai, jinhe body directly use nahi kar sakti. Isliye, food ko simpler substances mein break down karna zaroori hai.

• Nutrition ka process animals mein generally five steps mein hota hai:

1. Ingestion: Food ko body ke andar lena.
2. Digestion: Complex food substances ko simpler, soluble forms mein break down karna.
3. Absorption: Digested food ko blood ya lymph mein absorb karna.
4. Assimilation: Absorbed nutrients ko body ke cells tak pahunchana aur growth, repair, aur energy production ke liye use karna.
5. Egestion: Undigested food material ko body se remove karna.

• Har animal ka food intake ka method aur digestive system different hota hai, jo unke habitat aur food type par depend karta hai.

• Digestion ek biochemical process hai jisme enzymes complex food molecules ko simple ones mein convert karte hain.

Human digestive system ek long, muscular tube hai jise alimentary canal kehte hain, aur isme associated glands bhi hote hain jo digestive juices secrete karte hain. Alimentary canal approx. 9-10 meters long hoti hai.

• Alimentary Canal ke Parts (Food ka Path):

1. Mouth (Buccal Cavity): Food intake hota hai. Isme teeth, tongue aur salivary glands hote hain.

• Teeth: Food ko chew aur grind karte hain (mechanical digestion).
• Salivary Glands: Saliva secrete karte hain. Saliva mein salivary amylase (ptyalin) enzyme hota hai jo starch (carbohydrate) ko simple sugars mein break down karta hai. Isliye, chapati der tak chabane par meethi lagti hai (Activity 9.1).
• Tongue: Food ko saliva ke saath mix karta hai aur swallowing mein help karta hai.

1. Oesophagus (Food Pipe): Mouth se food ko stomach tak le jaata hai. Isme peristaltic movements hote hain (wave-like contractions aur relaxations) jo food ko push karte hain. [IMAGE: movement_of_food_in_the_food_pipe_fig92]
2. Stomach: Ek J-shaped muscular bag. Food yahan 3-4 ghante tak rehta hai.

• Gastric Glands: Stomach wall mein hote hain aur gastric juice secrete karte hain, jisme:
• Hydrochloric Acid (HCl): Food ko acidic banata hai, harmful bacteria ko kill karta hai, aur pepsin enzyme ko activate karta hai.
• Pepsin: Protein digestion start karta hai.
• Mucus: Stomach ki inner lining ko acid ke harmful effects se protect karta hai. [IMAGE: human_stomach_fig93]

1. Small Intestine: Alimentary canal ka sabse lamba part (approx. 6-7 meters). Yahan complete digestion aur absorption hota hai.

• Liver: Body ki sabse largest gland. Bile juice secrete karta hai jo fat ko emulsify karta hai (large fat globules ko smaller ones mein break karta hai). Bile juice gallbladder mein store hota hai.
• Pancreas: Pancreatic juice secrete karta hai jismein enzymes hote hain:
• Amylase: Carbohydrates ko digest karta hai.
• Trypsin: Proteins ko digest karta hai.
• Lipase: Fats ko digest karta hai.
• Intestinal Juice: Small intestine ki walls bhi intestinal juice secrete karti hain jismein enzymes hote hain jo carbohydrates, proteins aur fats ka final digestion karte hain.
• Villi: Small intestine ki inner surface par finger-like projections hote hain jinhe villi kehte hain. Ye surface area increase karte hain absorption ke liye. Har villus mein blood vessels ka network hota hai. [IMAGE: villi_in_the_small_intestine_fig95]
• Absorption: Digested food (glucose, amino acids, fatty acids, glycerol) villi ke through blood mein absorb ho jaata hai.

1. Large Intestine: Approx. 1.5 meters long. Undigested food small intestine se large intestine mein aata hai.

• Main function: Water aur kuch salts ka absorption undigested food se.
• Remaining waste semi-solid form mein ho jaata hai jise stool kehte hain.

1. Rectum: Stool ko temporarily store karta hai.
2. Anus: Undigested waste ko body se expel karta hai (egestion).

• Associated Glands: Salivary glands, Liver, Pancreas.

[IMAGE: human_alimentary_canal_fig94]

Animals mein digestion ke methods unke food habits ke according vary karte hain.

• Ruminants (Grass-eating animals):
• Examples: Cows, buffaloes, goats, deer.
• Ye animals grass खाते हैं jo cellulose rich hoti hai. Cellulose ko digest karna difficult hota hai.
• Inka stomach four chambers mein divided hota hai: Rumen, Reticulum, Omasum, Abomasum.
• Rumen: Sabse bada chamber. Grass ko initially yahan store karte hain aur partially digest karte hain (cud).
• Rumination: Partially digested food (cud) ko mouth mein wapas laakar dobara chew karte hain. Is process ko rumination kehte hain. Isse food particles ka surface area badh jaata hai for better digestion.
• Rumen mein bacteria aur protozoa hote hain jo cellulose ko digest karte hain.
• Thoroughly chewed food phir baki chambers se pass hota hai aur complete digestion hota hai.
• [IMAGE: digestive_system_of_a_ruminant_fig96]

• Birds:
• Birds ke paas teeth nahi hote. Wo food ko directly swallow karte hain.
• Inke digestive system mein kuch special structures hote hain:
• Crop: Food ko temporarily store aur soften karta hai.
• Gizzard: Ek muscular organ hai jismein grit (chote patthar) hote hain. Ye grit food ko grind karne mein help karte hain (mechanical digestion).
• Food crop se gizzard mein jaata hai, jahan mechanical breakdown hota hai, aur phir stomach aur intestine mein chemical digestion hota hai.
• [IMAGE: digestive_system_in_birds_fig97]

• Comparison: Human vs Ruminant vs Bird Digestion

| Feature | Humans | Ruminants | Birds | |:---------------|:-------------------------------------|:-------------------------------------------|:------------------------------------------| | Teeth | Present, for chewing | Present, for tearing/grinding | Absent | | Stomach | Single-chambered | Four-chambered (Rumen, Reticulum, Omasum, Abomasum) | Glandular stomach + Gizzard | | Digestion | Mechanical & Chemical in mouth, stomach, small intestine | Partial in Rumen, then re-chewing (rumination), then complete | Crop for storage, Gizzard for grinding, then chemical | | Cellulose Digestion | Absent | Present (by microbes in Rumen) | Absent | | Special Structures | Villi in small intestine | Rumen, Reticulum, Omasum, Abomasum | Crop, Gizzard |

Respiration ek vital life process hai jismein organisms food se energy release karte hain. Ye energy body ke various functions ke liye zaroori hoti hai.

• Breathing vs Respiration:
• Breathing: Physical process hai jismein air ko inhale aur exhale kiya jaata hai. Ismein sirf gases ka exchange hota hai (oxygen lena, carbon dioxide chhodna).
• Respiration: Biochemical process hai jismein cells ke andar food (glucose) ko break down karke energy release ki jaati hai. Ismein oxygen use hoti hai aur carbon dioxide produce hoti hai.

• Types of Respiration:

1. Aerobic Respiration: Oxygen ki presence mein hota hai.

• Glucose + Oxygen $\rightarrow$ Carbon dioxide + Water + Energy
• Zyada energy release hoti hai.
• Humans, animals mein common hai.

1. Anaerobic Respiration: Oxygen ki absence mein hota hai.

• Glucose $\rightarrow$ Alcohol/Lactic Acid + Carbon dioxide + Less Energy
• Kam energy release hoti hai.
• Yeast, kuch bacteria, aur human muscle cells mein temporary basis par (jab oxygen ki kami ho) hota hai.

• Animals mein respiratory organs unke habitat aur body structure ke according vary karte hain.

[IMAGE: cbse_c7_science_ch09_chapter_hero]

Human respiratory system air ko body mein lene aur bahar nikalne ke liye designed hai, aur gases exchange karta hai.

• Human Respiratory System ke Parts (Air ka Path):

1. Nostrils: External openings jahan se air enter karti hai. Hair aur mucus dust particles ko trap karte hain.
2. Nasal Passages: Nostrils se air nasal passages mein jaati hai, jahan air warm aur moist hoti hai.
3. Pharynx (Throat): Common passage for food and air.
4. Larynx (Voice Box): Sound production mein help karta hai.
5. Trachea (Windpipe): Cartilaginous rings se support hota hai taaki collapse na ho. Air ko lungs tak le jaata hai.
6. Bronchi: Trachea do tubes mein divide hoti hai, har ek lung mein jaati hai.
7. Bronchioles: Bronchi further smaller tubes mein divide hote hain.
8. Alveoli (Air Sacs): Bronchioles ke end par tiny, balloon-like structures hote hain. Ye gas exchange ki main site hain. Alveoli ki walls bahut thin hoti hain aur blood capillaries se surrounded hoti hain. [IMAGE: gas_exchange_in_alveoli_fig912]
9. Lungs: Main respiratory organs, rib cage se protected hote hain. Right lung mein 3 lobes aur Left lung mein 2 lobes hote hain.
10. Diaphragm: Chest cavity ke bottom par ek muscular sheet. Breathing mein important role play karta hai.

• Mechanism of Breathing:
• Inhalation (Saans andar lena):
• Diaphragm contract hokar niche move karta hai.
• Rib muscles contract hokar ribs ko upar aur bahar move karti hain.
• Chest cavity ka volume badh jaata hai.
• Lungs expand hote hain, aur air pressure lungs ke andar kam ho jaata hai.
• Atmospheric air lungs mein rush karti hai.
• Exhalation (Saans bahar nikalna):
• Diaphragm relax hokar wapas upar domed shape mein aata hai.
• Rib muscles relax hokar ribs ko niche aur andar move karti hain.
• Chest cavity ka volume kam ho jaata hai.
• Lungs contract hote hain, aur air pressure lungs ke andar badh jaata hai.
• Air lungs se bahar nikal jaati hai.
• [IMAGE: mechanism_of_breathing_fig910]
• [IMAGE: model_to_show_mechanisms_of_breathing_fig99] (Breathing mechanism ka model)

• Gas Exchange:
• Alveoli mein, oxygen blood mein diffuse karti hai aur carbon dioxide blood se alveoli mein diffuse karti hai.
• Blood oxygen ko body cells tak le jaata hai aur cells se carbon dioxide wapas lungs tak laata hai.

• Composition of Inhaled vs Exhaled Air:
• Inhaled Air: Oxygen ~21%, Carbon Dioxide ~0.04%
• Exhaled Air: Oxygen ~16-17%, Carbon Dioxide ~4-5%
• Ye difference gas exchange ko clearly show karta hai. [IMAGE: composition_of_inhaled_and_exhaled_air_fig913]

• Cellular Respiration: Cells ke andar food (glucose) ka breakdown energy release karne ke liye.
• Word Equation: Glucose + Oxygen $\rightarrow$ Carbon dioxide + Water + Energy

[IMAGE: human_respiratory_system_fig98]

Different animals ne apne environment ke according specialized respiratory organs develop kiye hain.

• Lungs: Birds, elephants, lions, cows, goats, lizards, snakes jaise terrestrial animals lungs se breathe karte hain, jaise humans karte hain.

• Gills: Most aquatic animals, jaise fish, gills se breathe karte hain.
• Gills feathery structures hote hain jo blood vessels se richly supplied hote hain.
• Fish mouth se water leti hai, aur water gills ke upar se flow hota hai.
• Gills water mein dissolved oxygen ko absorb karte hain aur carbon dioxide ko water mein release karte hain.
• [IMAGE: gills_in_fish_for_respiration_fig914]

• Skin: Earthworms aur frogs (jab water mein ho) apni moist skin se gas exchange karte hain.
• Skin thin aur moist honi chahiye taaki gases easily diffuse ho sakein.

• Tracheal System: Insects (e.g., cockroaches) mein tracheal system hota hai.
• Tiny air tubes (tracheae) ka network hota hai jo body surface par spiracles (chote openings) se khulte hain.
• Air directly cells tak pahunchti hai, blood ka role gas transport mein minimal hota hai.

• Amphibians (e.g., Frogs):
• Tadpoles (larval stage): Gills se breathe karte hain (aquatic respiration).
• Adult Frogs: Land par lungs se breathe karte hain. Water mein ya hibernation ke dauran moist skin se breathe karte hain.

• Summary of Respiratory Organs:

| Animal Group | Respiratory Organ(s) | Habitat | Key Feature | |:---------------|:---------------------|:----------|:------------------------------------------| | Humans, Mammals, Birds, Reptiles | Lungs | Terrestrial | Internal, protected, large surface area | | Fish | Gills | Aquatic | Extract dissolved oxygen from water | | Earthworms | Moist Skin | Terrestrial (damp soil) | Direct diffusion through skin | | Insects | Tracheal System | Terrestrial | Direct air delivery to cells via tubes | | Frogs (Tadpoles) | Gills | Aquatic | Similar to fish gills | | Frogs (Adult) | Lungs, Moist Skin | Terrestrial & Aquatic | Dual mechanism based on environment |