Faculty of translation theoretical phonetics

Birds. Birds

Birds also evolved from reptiles about 150 million years ago. Today, more than 9000 species are represented on our planet. Birds have a number of characteristics that distinguish them from other vertebrates. This feather (feathers), beak (bill) and thymus bone in the skeleton (furcula). Birds are notable for their ability to fly over its territory, each with its own characteristics and. So, albatrosses (albatrosses) are characterized in that fly over the sea, hummingbirds (hummingbirds) can fly backwards, and raptors (birds of prey) catch
their prey with amazing speed and agility. Interestingly, not all birds can fly. Some species, such as ostriches (ostriches), kiwi fruit (kiwis) and penguins (penguins), lost the ability to fly for a long time and have adapted to life in the water or on land.
Key characteristics of birds:

1. 
   Vertebrates — vertebrates.
   
2. 
   Tetrapods — four-legged.
   
3. 
   Endothermic — warm-blooded.
   
4. 
   Feathers — feathers.
   
5. 
   Bills — beaks.
   
6. 
   Furcula — thymus bone.
   
7. 
   No teeth — teeth are missing.
   
8. 
   Four-chambered heart and high metabolic rates — 4-chambered heart, and a fast metabolism.
   
9. 
   Eggs production — the birds lay eggs.
   

The number of animal species (vertebrates and invertebrates) on planet Earth is much higher than the number of flora species due to the fact that only the insects are represented by almost 1 million different species.

Let’s see the numbers that are defining the known animal species on the planet:
Vertebrates

• 
  Mammals 5,416 known species;
  
• 
  Reptiles 8,240 known species;
  
• 
  Birds 9,956 known species;
  
• 
  Fish 30,000 known species;
  

• 
  Birds 9,956 known species;
  
• 
  Amphibians 6,199 known species.
  

Invertebrates

• 
  Insects 950,000 known species;
  
• 
  Molluscs 81,000 known species;
  
• 
  Crustaceans about 40,000 species;
  
• 
  Corals 2,175 known species;
  
• 
  Others 130,200 species.
  

All these numbers will be changed soon or have been already changed to higher values due to the fact that every year about 10,000 new species of animals (vertebrates and invertebrates) are discovered.

Fauna Subdivisions
Fauna has many subdivisions created to describe in detail all the creatures known today and the creatures that will be discovered in the future (from the very big ones to the very tiny ones).
Cryofauna
Cryofauna describes the animals that live very close or on the ice.
Here we have orcas, Rockhopper penguins, Emperor penguins, Adelie penguins, Crabeater seals, Weddell seals and the Black-browed Albatross.
Cryptofauna
Cryptofauna describes the animals that live in protected or concealed microhabitats.

We have here Polychaeta, Crustacea, Mollusca, Echinodermata and some tiny fishes.

Infauna
Infauna represents the benthic organisms that live within the bottom substratum of a body of water, such as the bottom-most oceanic sediments.
We have here clams, snails, flatworms, polychaetes and small crustaceans.
Bacteria and microalgae can also be found within the bottom substratum of the oceans.
Epifauna
Epifauna represents the aquatic animals that live on the bottom substratum of the oceans and not within the stratum.
Here we have oysters, sea squirts, sponges, barnacles and sea stars.
Macrofauna
Macrofauna are the benthic or soil organisms that are retained on a 0.5 mm sieve.
The deep sea studies are defining macrofauna as the animals that are retained on a 0.3 mm sieve.
Here we have potworms, centipedes, myriapods, slugs, millipedes, fly larvae, beetles, beetle larvae, and spiders.
Megafauna
Megafauna describes the large animals that live in a particular region or time.

We have here the Australian megafauna, the Pleistocene megafauna (extinct during the Quaternary extinction event) and many others.

Meiofauna
Meiofauna describes the small benthic invertebrates that are specific to both marine and freshwater environments.
Meiofauna represents a group of organism that are larger in size than microfauna but smaller than macrofauna.
Mesofauna
Mesofauna represents the macroscopic soil animals (arthropods and nematodes).
Mesofauna is very diverse, about 6,500 species have been already discovered.
Microfauna
Microfauna describes the microscopic or very tiny animals.
Here are usually included protozoans and very small animals such as rotifers.
Avifauna
Avifauna (birds) is describing a group of endothermic vertebrates that have feathers and toothless beaked jaws.
These are flying creatures that lay hard-shelled eggs, have a high metabolic rate, a four-chambered heart, and a pretty strong yet lightweight skeleton.
Piscifauna
Piscifauna (Ichnyofauna) refers to all the fishes on the planet that live both in

freshwater and in sea water.