python3: different pip package lists

I get two different lists of python packages depending on how run pip list command (see below). Can someone help me understand why there is a difference?

Code:me:~$ pip3 list
Package Version
-------------- -------
pdftotext 2.1.4
pip 21.0.1
python-poppler 0.2.1
setuptools 41.2.0
wheel 0.34.2Code:me:~$ python3 -m pip list
Package Version
---------------------- --------------------
appdirs 1.4.3
certifi 2019.11.28
chardet 3.0.4
cryptography 2.8
cupshelpers 1.0
dbus-python 1.2.16
distlib 0.3.0
distro 1.4.0
distro-info 0.23ubuntu1
dnspython 1.16.0
eyeD3 0.8.10
filelock 3.0.12
gpg 1.13.1-unknown
gpodder 3.10.15
html5lib 1.0.1
idna 2.8
importlib-metadata 1.5.0
kazam 1.4.5
Markdown 3.1.1
more-itertools 4.2.0
mygpoclient 1.8
packaging 20.3
pdftotext 2.1.4
pip 21.0.1
podcastparser 0.6.4
pycairo 1.16.2
pycrypto 2.6.1
pycups 1.9.73
Pygments 2.3.1
PyGObject 3.36.0
pyparsing 2.4.6
python-apt 2.0.0+ubuntu0.20.4.4
python-magic 0.4.16
python-poppler 0.2.1
pyxdg 0.26
PyYAML 5.3.1
requests 2.22.0
setuptools 45.2.0
simplejson 3.16.0
six 1.14.0
ubuntu-advantage-tools 20.3
urllib3 1.25.8
virtualenv 20.0.17
webencodings 0.5.1
wheel 0.34.2
zipp 1.0.0