7. [ Auto-Generated ] Structural Organization In Animals

From Cells to Systems

Ever wonder how complex animals are built? It’s all about teamwork! Unlike unicellular organisms where one cell does it all, multicellular animals organize their bodies to handle complex functions.

The Hierarchy of Organization

Just like bricks build a house, biological units build up step-by-step:

• Cells: The starting point. In humans, billions of cells work together.
• Tissues: A group of similar cells working together with intercellular substances to perform a specific function.
• Organs: Tissues organized in specific proportions to form structures like the stomach, heart, or kidney.
• Organ Systems: Two or more organs interacting physically or chemically to perform a common function (e.g., the digestive system).

Division of Labour

In complex animals, not every cell does every job. Instead, they split up the work.

Division of Labour means that specialized cells, tissues, organs, and systems handle specific tasks. This efficient organization allows the body to function better and ensures the survival of the organism as a whole!

Meet the Frog: Rana tigrina

Did you know frogs can live on both land and in freshwater? The most common species found in India is the Rana tigrina (Indian Bullfrog).

Classification

Biologists classify these jumping creatures under:

• Phylum: Chordata
• Class: Amphibia

Cold-Blooded Nature

Frogs are cold-blooded animals, or poikilotherms. This means they do not have a constant body temperature; instead, it changes with the environment.

To survive extreme weather, they take shelter in deep burrows:

• Aestivation: Summer sleep to protect against heat.
• Hibernation: Winter sleep to protect against cold.

Did you know? Frogs can change color to hide from enemies! This protective camouflage is called mimicry.

Skin and Senses

Let's explore the frog's unique body covering and specialized sensory organs found on the head!

🐸 The Skin

A frog's skin is vital for its survival:

• Texture: It feels smooth and slippery due to the presence of mucus.
• Moisture: The skin is always maintained in a moist condition.
• Color: Generally olive green with dark spots on the back (dorsal side) and uniformly pale yellow on the belly (ventral side).
• Hydration: Frogs never drink water! Instead, they absorb water directly through their skin.

👀 Sensory Organs

Frogs have specialized features to help them sense their environment:

• Eyes: These are bulged and covered by a nictitating membrane. This membrane acts like built-in goggles, protecting the eyes while the frog is underwater.
• Tympanum: Located on either side of the eyes, this membranous structure acts as the ear and receives sound signals.