What is the default select of XSLT apply-templates?

The identity template looks like this:

<xsl:template match="@*|node()">
    <xsl:copy>
        <xsl:apply-templates select="@*|node()" />
    </xsl:copy>
</xsl:template>

Does <xsl:apply-templates select="@*|node()" /> select more than <xsl:apply-templates />, or could the identity template have been like this?

<xsl:template match="@*|node()">
    <xsl:copy>
        <xsl:apply-templates />
    </xsl:copy>
</xsl:template>

What exactly is selected when I do the following?

<xsl:apply-templates />