Jelly Fish

Ecological Significance

blend in with their surroundings

members of phylum cnidaria

evade predators

Body Structure

Rhopalia

contain light-sensitive cells called photoreceptors

allow jellyfish to detect light and perceive their environment

gelatinous and umbrella-shaped body called a bell

transparent and composed mostly of water

divided into an exumbrella and subumbrella surface

tentacles used for capturing preys

5% percent of jellyfish bodies are made of structural proteins, muscles, and nerve cells

Life Cycle

both sexual and asexual reproduction

medusa stage

release eggs and sperm for sexual reproduction

polyp stage

reproduce asexually by budding

Movement

pulsating motion

achieved by contracting and relaxing the muscles surrounding the bell

Nervous System

decentralized nerve net

interconnected neurons that transmit electrical impulses

coordinates basic sensory and motor function

It allows jellyfish to respond to light or touch

perform simple behaviors like swimming and feeding

Muscular System

Circular and radial muscles surround their bell and tentacles

tentacles contain muscles that enable them to extend, contract, and move

Digestive System

rudimentary digestive system

gastrovascular cavity

prey is brought to here

Digestive enzymes

break down the food

nutrients are then absorbed into the jellyfish's body for energy

Transparency and Light Transmission

high transparency due to their gelatinous bodies

allows light to pass through with minimal scattering or absorption

can still undergo scattering or absorption

enables jellyfish to transmit light throughout their bodies

sensitivity to specific wavelengths

interact with light in various ways

can fluoresce when illuminated by ultraviolet (UV) light

Bioluminescence

production of light by specialized cells called photocytes

emit light in various colors (e.g., green, blue, and sometimes red)

serves purposes like attracting prey, repelling predators, and communication

Photoproteins

produce light through the action of photoproteins within their photocytes

undergo a chemical reaction

emits light with entry of calcium ions

can determine the color and intensity of the emitted light

Refraction

index between their tissues and the surrounding water

bending and redirection of light rays

Scattering

due to irregularities in the jellyfish's tissue

variations in density or surface structures

diffuse illumination within the jellyfish

Composition

95% to 98% of their body mass is water

Molecular Composition

carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur

Proteins

vital in the structure and function of their cells and tissues

composed of amino acids

Photoprotein

consist of a protein component and a non-protein component

chromophore : undergoes a chemical reaction to emit light

can emit light with calcium ion Ca2+

Mucus

a gelatinous substance

reduce friction in the water