Is there a reason for the E Value to differ when using BLAST on the web and using BioPython? My understanding is that these are the same source, so I am unable to understand the following differences.

As an example, consider the sequence

tpdavmgnpk

Submit this to blastp and compare it with the following python script:

from Bio.Blast import NCBIWWW
from Bio.Blast import NCBIXML

peptide = "tpdavmgnpk"
myEntrezQuery = "Homo sapiens[Organism]"
result  = NCBIWWW.qblast("blastp", "nr", peptide,entrez_query=myEntrezQuery)

records = NCBIXML.parse(result)
blast_record = records.next()

for alignment in blast_record.alignments:
    for hsp in alignment.hsps:
        if hsp.expect < 5:
            print "***** RECORD ****"
            print "sequence:", alignment.title
            print "E-value:", hsp.expect

Here are two examples of differing E values I obtain

Accession, Biopython E value, NCBI web E value

AAW66689.1 1.20033, 0.045

AAA53153.1 1.21977, 0.075

EDIT: I have tried making the defaults similar (Peter's answer and Ben's comment) and this link:

result  = NCBIWWW.qblast("blastp", "nr", peptide,entrez_query=myEntrezQuery,matrix_name='BLOSUM62',word_size='2',expect='50000',gapcosts='11 1',composition_based_statistics='no adjustment')

The results are still not matching.

Thanks!