Animal Behavior
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Animal Behavior
The handwritten notes divide animal behavior into two broad types:
1. Learned Behavior
The source describes it as a non-inherited type of behavior and gives examples such as:
2. Innate Behavior
The source lists the following under innate behavior:
Reflex Action
Examples Listed in the Source
- Constriction of the pupil in response to an intense light source.
- Release of saliva.
- Swallowing food.
- Blinking of the eye when an object passes close to the eye.
- Withdrawal of the hand on touching a hot object.
- Jerking of the knee.
- Paleness of skin or erection of hair as a result of fear.
Sensory and Motor Nerves
Carry messages or impulses from receptors toward the central nervous system.
Carry messages from the central nervous system toward the responding body part.
Taxis, Tropism and Kinesis
Taxis
Tropism
Kinesis
| Behavior | Main Character in the Source |
|---|---|
| Taxis | Directional movement with displacement. |
| Tropism | Mostly plant orientation; direction changes without displacement as described in the notes. |
| Kinesis | Non-directional or haphazard movement. |
Types of Taxis
I. On the Basis of Direction of Movement
Movement of an animal toward the source of stimulus.
Example: some insects move toward a light source at night.
Movement of an organism away from the source of stimulus.
Example: earthworm moves away from a light source.
II. On the Basis of Type of Stimulus
Phototaxis
Movement of an organism toward or away from the source of light.
- Positive: moth is attracted by light at night.
- Negative: earthworm goes away from light.
Thermotaxis
Movement of an animal in response to temperature.
Chemotaxis
Movement of an animal in response to a chemical stimulus.
- Positive: the source gives movement toward sugar solution.
- Negative: earthworm moves away from formalin.
Geotaxis
Response of an animal toward gravity.
- Positive: earthworm moves toward the earth / underground.
- Negative: arboreal animals move opposite to the earth’s surface as described in the notes.
Thigmotaxis
A kind of taxis shown by animals in response to touch.
Rheotaxis
Response of an animal to flowing water or water current.
- Positive: hill-stream fishes such as Glyptothorax move against the water current.
- Negative: the source states that some fishes move with the flow of water.
Galvanotaxis
Response of an animal to the stimulus of an electric current.
Dominance and Leadership
The source describes dominance as a social and innate behavior in which a dominant individual asserts itself over the group.
Leadership is also described as social and innate behavior. The leader of the group gives guidance, coordinates members and looks after the welfare of the group.
Migration
Fish Migration
The notes classify fish migration in several ways:
Fish Migration on the Basis of Purpose
Alimental Migration
Migration mainly for feeding purposes. The source gives examples such as grass carp and Chinese carp moving from one place to another in search of a better feeding place.
Spawning Migration
Migration for spawning or reproduction. Salmon and eel are listed as examples of fishes moving between sea and river environments for breeding.
Climatic Migration
Migration caused by climatic conditions. The source describes fishes moving between different water conditions to protect themselves from unfavorable seasonal temperature.
Osmoregulatory Migration
Movement between sea and river for balancing water and mineral concentration in the body, especially under unfavorable conditions.
Over-wintering Migration
Migration from feeding grounds to wintering grounds. The notes state that some fishes enter a hibernation-like state during winter.
Fish Migration on the Basis of Purpose and Route
A. Diadromous Migration
The source divides diadromous migration into three types:
Fishes such as salmon and hilsa move from salty or sea water to fresh water for breeding.
Freshwater eels such as Anguilla move from fresh water or rivers to salty sea water.
Fishes move between sea and river mainly for feeding, not for breeding. The source gives globe fish as an example.
B. Potadromous Migration
C. Oceanodromous Migration
Fish Migration on the Basis of Direction
Latitudinal Migration
Migration from north to south or vice versa.
Examples: barracuda (Sphyraena) and swordfish (Xiphias).
Vertical Migration
Daily movement between deep and surface waters for food, protection or spawning. The source mentions swordfish and fishes of the group Scopeliformes.
Shoreward Migration
Temporary movement of fishes from water toward land or shore. The common eel is given as an example in the source.
Causes of Fish Migration
Physical Factors
Chemical Factors
Biological Factors
Advantages of Fish Migration
- Helps fishes avoid unfavorable conditions.
- Provides better opportunities for feeding and breeding.
- Provides safer or more suitable dwelling conditions.
Disadvantages of Fish Migration
- Migratory fishes are exposed to many risks during migration.
- They may die because of adverse climatic conditions.
- Lack of food, disease and predation may cause mortality during the journey.
Bird Migration
Types of Bird Migration
Latitudinal Migration
Migration of birds from north to south or vice versa.
Example in the source: golden plovers migrating from North America to Argentina to spend winter.
Altitudinal Migration
Migration of birds from high mountains to lowlands or vice versa; also called vertical migration.
The source lists grebes and coots of the Andes and violet-green swallows among its examples.
Longitudinal Migration
Migration of birds from east to west or vice versa.
Seasonal Migration
Movement caused by seasonal changes.
Examples: snow bunting, fieldfare and redwing are listed as winter visitors.
Daily or Local Migration
Short-distance migration. The source gives house sparrow, golden crow and oriole as examples and states that they return to the nest afterward.
Partial Migration
Migration covering distances from a few to hundreds of miles.
Examples: herons and cranes.
Modes of Flight in Bird Migration
1. Diurnal and Nocturnal Migrants
Birds that migrate during daytime.
Examples: hawks, crows, robins and bluebirds.
Birds that migrate at night.
Examples: warblers, sparrows and thrushes.
2. Altitude, Speed and Distance of Migration
3. Routes of Migration
Migratory birds usually follow the same route year after year. According to the notes, the position of the sun, stars and the Earth’s magnetic field help guide them along the route.
Causes of Bird Migration
The source mentions completion of the sexual cycle, hormonal secretions and metabolic activities.
Temperature, snowfall, climatic changes, scarcity of food, shortening of daylight, increase in cold and velocity of wind are listed.
Advantages of Bird Migration
- Helps birds avoid extreme cold or hot conditions.
- Provides more food and better feeding and breeding places.
- Helps birds obtain suitable nesting places.
Disadvantages of Bird Migration
- Migration is a risky process.
- Birds may be killed by severe climatic conditions such as heavy rainfall, snowfall or stormy wind.
- They may be killed by predators such as humans and hawks, as listed in the source.
- Some birds may die after striking lighthouses, monuments, large buildings or television towers.
- Some birds may lose their way during severe weather and drown in the sea.
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