oceanic neckton

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oceanic neckton by Mind Map: oceanic neckton

1. epipelagic zone

2. epipelagic environment *organisms with powers of locomotion *Predominantly vertebrates, fishes being most numerous

3. taxonomy -*Wide variety of bony fishes, sharks, rays

3.1. holoepipelagic *blue shark, flying fish, tuna, marlins, swordfish *Lay floating eggs and have epipelagic larvae

3.1.1. holoepipelagic

3.2. Meroepipelagic-diverse group including herring, whale, shark, dolphin fish, half beaks *Spawn in inshore waters but live in epipelagic

3.2.1. meroepipelagic

4. environmental conditions : are factors that affect the environment in the sea environment

4.1. light

4.2. temperature

4.3. density

4.4. three dimensional

4.4.1. Three-dimensionality enables evolution of great mobility and ability to cover large distances

4.5. no solid substrate

4.5.1. Lack of substrate means no firm support and more dense than seawater

5. adaptations of necktons

5.1. Buoyancy-most significant and important, need to stay afloat Most nektonic animals have density similar to seawater and are neutrally buoyant

5.2. locomotion Two groups-to create propulsive forces and reduce resistance of body to movement in water

5.3. adaptations Surface resistance and body shape- seawater is dense, requires lots of energy and resistance to move through

5.3.1. Frictional proportional to amount of surface area in contact with water

5.3.2. Form drag is proportional to cross-sectional area in contact with the water

5.3.3. Induced drag or turbulence due to changes in speed direction of the flow

5.3.4. Body shape - teardrop shape gives lowest resistance

6. camouflage *Little need to evade predators as most neckton are large or fast moving *Camouflage is used in defense

6.1. Transparency not an option for nekton due to size and complexity

6.2. Body shape alteration occurs as long as shape does not interfere with fast locomotion

6.3. Cryptic coloration common-dark blue or green color on dorsal surfaces and white or silver on ventral side to avoid predators

6.4. jhgf

7. sensory organs Have well-developed sense organs some with specialized senses

7.1. Mammals have geomagnetic sensory system for long-distance navigation

7.2. Lateral lines in fish, rows of small tubes open to water with sensory pits to detect pressure changes

8. Echolocation *Hearing in mammals has greatest number of adaptations *Sound reception and production most highly developed in cetaceans with echolocation

8.1. Some mammals use low-frequency to communicate among themselves

8.2. high-frequency waves used to determine fine structure of objects

9. Reproduction and life cycle

9.1. Fish have rapid growth rate and fairly short lives, tuna (5-10 yrs) sharks (20-30yrs)

9.2. Marine birds and turtles reproduce on land migrating every year to breeding grounds

9.3. Mammals have two groups: birth on land and underwater

9.3.1. kkhhSeals, sea lions, walruses give birth on land or ice

9.3.2. Cetaceans give birth in water protected by mother, migrate to breeding areas in calm, warm waters

10. Migration breeding common in air-breathing marine vertebrates

10.1. Fish also migrate great distances but little known as to why, eg tuna

10.2. Sea turtles also do same over great distances

11. Adaptations of marine birds and mammals

11.1. Maintaining temperature- larger body, smaller surface area relative to volume

11.2. Diving-most mammals capable of diving

11.3. Circulatory-larger blood volume holds more oxygen and increases oxygen capacity

11.4. Osmotic regulation needed as salt lower in body than surrounding seawater