Differences between animals created on the fifth and the sixth days

Question

IIRC, the Jewish tradition divides between inanimated nature, plants, animal kingdom, and humans. I'm not aware of any principal differences within the animal kingdom. However, in the Creation narrative, some creatures are created on the 5th day (Genesis.1.20):

וַיֹּאמֶר אֱלֹהִים יִשְׁרְצוּ הַמַּיִם שֶׁרֶץ נֶפֶשׁ חַיָּה וְעוֹף יְעוֹפֵף עַל־הָאָרֶץ עַל־פְּנֵי רְקִיעַ הַשָּׁמָיִם׃ וַיִּבְרָא אֱלֹהִים אֶת־הַתַּנִּינִם הַגְּדֹלִים וְאֵת כׇּל־נֶפֶשׁ הַחַיָּה  הָרֹמֶשֶׂת אֲשֶׁר שָׁרְצוּ הַמַּיִם לְמִינֵהֶם וְאֵת כׇּל־עוֹף כָּנָף לְמִינֵהוּ...׃
God said, “Let the waters bring forth swarms of living creatures and birds that fly above the earth across the expanse of the sky. God created the great sea monsters, and all the living creatures of every kind that creep, which the waters brought forth in swarms, and all the winged birds of every kind.

And some on the 6th:

וַיֹּאמֶר אֱלֹהִים תּוֹצֵא הָאָרֶץ נֶפֶשׁ חַיָּה לְמִינָהּ בְּהֵמָה וָרֶמֶשׂ וְחַיְתוֹ־אֶרֶץ לְמִינָהּ וַיְהִי־כֵן׃
God said, “Let the earth bring forth every kind of living creature: cattle, creeping things, and wild beasts of every kind.” And it was so.

Rashi interprets "נפש חיה. שֶׁיֵּשׁ בָּהּ חַיּוּת:", but does he explicitly (לאפוקי) mean that those created on the day before lacked vitality?

From the ontological point, what is the principal difference between those two groups of the animal kingdom?

Answer 1

Rabbeinu Bachaye on 1:24 answers that the terms נפש חיה in 1:20 and 1:24 are not the same. The former, on fish, birds and bugs refers to a נפש that is a form of life that is higher than plants predominantly because they can move (see his commentary on 1:20 about the 5 types of movement etc).

The collective living soul that is referred to in 1:24, which humans share with more complex animals, is one step higher, and predominantly because it is intelligent.

Humans may share a part of their life force with animals, but also have a life force that is unique, hinted at the fact that man was made together with the Earth, where as animals (and the other category including fish and birds) are brought forth from the Earth. There are many ontological differences with this category, including the fact that man's intelligence is Godly, possessing the power of speech and free will. The philosophical and Kabbalistic explanations of this are brought in his commentary on 1:27.