Question: How are James Earp and Nicholas Porter Earp related?

Context paragraphs:
Hour of the Gun: Hour of the Gun is a 1967 Western film depicting Wyatt Earp and Doc Holliday during their 1881 battles against Ike Clanton and his brothers in the Gunfight at the O.K. Corral, and the gunfight's aftermath in and around Tombstone, Arizona, starring James Garner as Earp, Jason Robards as Holliday, and Robert Ryan as Clanton.  The movie was directed by John Sturges.

Glenn Boyer: Glenn G. Boyer (January 5, 1924 - February 14, 2013) was a controversial author who published three books and a number of articles about Wyatt Earp and related figures in the American Old West.  He was the first person to reveal the existence of Wyatt Earp's second wife, Mattie Blaylock.  His publications were for many years regarded as the authoritative source on Wyatt Earp's life.  However, when other experts began to seek evidence supporting Boyer's work, he would or could not prove the existence of documents that he said he owned and had cited as essential sources.  In one case, an individual he cited as a key source was exposed as a complete fabrication.  His reputation and the authenticity of his work was seriously damaged.  Although he retained many supporters, his work became surrounded by controversy.

James H. Kelley: James H. Kelley, also known as Dog Kelley (c .  1833 - September 8, 1912), was an American frontiersman and businessman who as the mayor of Dodge City, Kansas, briefly supervised the law-enforcement careers of such officers as the Earp and Masterson brothers: Wyatt and Morgan Earp and Bat, Ed, and James Masterson.

Sunset (film): Sunset is a 1988 American mystery action film written and directed by Blake Edwards and starring Bruce Willis as legendary Western actor Tom Mix, who teams up with legendary lawman Wyatt Earp, portrayed for the second time in a theatrical film by James Garner.  Based on an unpublished novel by Rod Amateau, the plot has Mix and Earp team up to solve a murder in Hollywood in 1929.

James Earp: James Cooksey Earp (June 28, 1841 – January 25, 1926) was a lesser known older brother of Old West lawman Virgil Earp and lawman/gambler Wyatt Earp.  Unlike his brothers, he was a saloon-keeper and was not present at the Gunfight at the O.K. Corral on October 26, 1881.

Nicholas Porter Earp: Nicholas Porter Earp (September 6, 1813 – February 12, 1907) was the father of well-known Western lawmen Virgil, Wyatt, and Morgan, and their lesser-known brothers James and Warren Earp.  He was a justice of the peace, a farmer, cooper, constable, bootlegger, wagon-master, and teacher.

Warren Earp: Warren Baxter Earp (March 9, 1855 – July 6, 1900) was the youngest brother of Wyatt, Morgan, Virgil, James, and Newton Earp.  Although he was not present during the Gunfight at the O.K. Corral, after Virgil was maimed in an ambush, Warren joined Wyatt and was in town when Morgan was assassinated.  He also helped Wyatt in the hunt for the outlaws they believed responsible.  Later in life, Warren developed a reputation as a bully and was killed in an argument in 1900.

Jimmy Noel: Jimmy Noel (May 15, 1903–January 31, 1985) was a Massachusetts-born actor and stuntman who appeared in hundreds of largely uncredited roles in film and television between 1949 and 1975.  He appeared 202 times on CBS's western series, "Gunsmoke", starring James Arness, and in 144 episodes of the ABC/Desilu production, "The Life and Legend of Wyatt Earp", with Hugh O'Brian in the title role of deputy Marshal Wyatt Earp.  Buddy Roosevelt made similar appearances in sixty-five "Wyatt Earp" episodes.

Newton Earp: Newton Jasper Earp (October 7, 1837 – December 18, 1928) was the eldest child of Nicholas Porter Earp and Abigail Storm.  He was the half-brother of Old West lawmen Wyatt, Virgil, and Morgan Earp.

Fitzsimmons vs. Sharkey: The Fitzsimmons vs Sharkey Heavyweight Championship boxing match between Bob Fitzsimmons and Tom Sharkey was awarded by referee Wyatt Earp to Sharkey after Fitzsimmons knocked Sharkey to the mat.  Earp ruled that Fitzsimmons had hit Sharkey when he was down, but very few witnessed the purported foul.  The fans at the December 2, 1896 fight in San Francisco booed Earp's decision.  It was the first heavyweight championship fight since James J. Corbett, the prior champion, had retired from boxing the year before.  The fight may have been the most anticipated fight on American soil that year.

Supporting paragraphs: Nicholas Porter Earp James Earp
Answer: Earp