Science under modern classification systems, in what clade will you find birds?

Birds evolved from reptiles in Mesozoic era and their ancestors are small dinosaurs called theropods while they belong to class aves.

Further Explanation

Birds as dinosaurs

They are evolved in Mesozoic era either from thecodonts or theropods. These are two possibilities.

Thecodonts hypothesis

These are earlier reptiles which gave rise to dinosaurs (arboreal dinosaurs called pterosaurs and crocodiles) in Mesozoic era. Their body was covered with scales.

Theropods

They were bipedal carnivorous dinosaurs having sharp teeth to tear their prey. Earlier they were non-flying and gave rise to small flying dinosaurs. Their fossil study reveals that they were similar to birds.

Birds as reptiles

Taxonomic study reveals that birds are descendants of reptiles and fossil of Archaeopteryx lithographica is the evidence.

Archaeopteryx lithographica

Archaeopteryx was first fossils of birds that was found in Bavarian quarry by a German naturalist. It was crow sized, bipedal, with small snout having sharp teeth, strong muscles and large furcula.

Archaeopteryx Vs modern birds

Modern birds possess larger brain with enlarged visual center as compared to archaeopteryx. Modern birds had evolved advance neural system for flight.

Aves

It is class of vertebrate birds having characteristics like bill, wishbone, pygostyle and furcula.

Answer details

Subject: Biology

Level: High school

Key words

Birds as dinosaurs

Thecodonts hypothesis

Theropods

Birds as reptiles

Archaeopteryx lithographica

Archaeopteryx Vs modern birds

Aves

Learn more to evaluate

water is a polar molecule. a chemical bond is a force of attraction between atoms or ions. bonds form when atoms share or transfer valence electrons. atoms form chemical bonds to achieve a full outer energy level, which is the most stable arrangement of electrons. so, false

explanation:

in h2o molecule, two water molecules are bonded by a hydrogen bond but the bond between two h - o bonds within a water molecule are covalent. the greater the electronegativity difference, the more ionic the bond is. bonds that are partly ionic are called polar covalent bonds. nonpolar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal.

yes we can.   a lady urinates from her urethra.