Can the evening and morning Kriyas Shema be read consecutively?

If circumstances prevented a person from being able to recite the nighttime Kriyas Shema before daybreak, he may say it b’dieved until hanetz hachamah. The brochos, except for Hashkiveinu, may also be recited. Shulchon Aruch rules that if a person recited the evening Shema during this interval, he may not say the daytime Shema afterwards. Although under pressing circumstances it is permissible to say the daytime Shema during this period, in this situation--when one was just yotzei the nighttime Shema—doing so would seem like a contradiction. Other poskim allow both Shemas to be said during this period and are not concerned with the inconsistency. If a person neglected to recite the nighttime Shema until after daybreak without being an ones, he is not yotzei.

סעיף ה וס"ק ה-כב

What is the deadline for Birchos Kriyas Shema?

A person who did not read Kriyas Shema at the proper time can still say it, along with its brochos, until the fourth halachic hour of the day. Although the time for Shema has passed, the brochos are not directly connected to Shema and may be said for an additional hour. Reciting the first two parshios of Shema is optional after the third hour, but one is still obligated to say the third parsha. The mitzvah of remembering yetzias Mitzrayim can be done throughout the day. After the fourth hour, Birchos Kriyas Shema can no longer be said. If one was an ones, there is room to be lenient and recite it before chatzos.

סעיף ו ס"ק כו-כז, וביה"ל ד"ה קוראה; ביאורים ומוספים דרשו, 26 ;וראה שם, 28

Is there a way to make up for a missed Kriyas Shema?

If a person mistakenly missed a tefillah, he can do a tashlumin (a make-up tefilla) during the next time for tefillah. Some Rishonim apply this concept to Kriyas Shema. They say that if a person missed saying Shema, he should recite it twice when the time comes to say it again. Although he does not actually fulfill the mitzvah, it is worthwhile to recite it again as a make-up. Others hold that there is no purpose in saying Kriyas Shema twice the next time.  

סעיף ז וס"ק כח-כט

• A person who will not be able to say Kriyas Shema from misheyakir until the end of the third hour of the day may say it beforehand at alos hashachar.

• If a person is able to say Shema at the proper time, but he would only be able to lay tefillin at alos, some poskim say that he should recite Kriyas Shema with tefillin at alos.

• Even if a person does not say Shema at sunrise, he must be certain to say it at the first possible time.

• Can a brocha be corrected?

• How soon must a correction be made?

• Which part of a brocha must be mistake-free in order to be yotzei?