{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Ch23_Lecture - 23 Species and Their Formation 23 Species...

Info icon This preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
23 Species and Their Formation
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
23 Species and Their Formation 23.1 What Are Species? 23.2 How Do New Species Arise? 23.3 What Happens when Newly Formed Species Come Together? 23.4 Why Do Rates of Speciation Vary? 23.5 Why Do Adaptive Radiations Occur?
Image of page 2
23.1 What Are Species? Species literally means “kinds.” We recognize most species by their appearance. Many species change little over large geographic ranges.
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
23.1 What Are Species? Linnaeus described species based on their appearance—the morphological species concept . Members of species look alike because they share many alleles. He originated the binomial system of nomenclature.
Image of page 4
23.1 What Are Species? But males and females may not look alike. Immature individuals may not look like their parents. Other types of information must be used to determine species.
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
23.1 What Are Species? Species can be thought of as branches on the tree of life. Speciation : The process by which one species splits into two or more daughter species, often gradually.
Image of page 6
23.1 What Are Species? Speciation involves reproductive isolation —when individuals of a population mate with each other, but not with individuals in another population, they are a distinct evolutionary unit.
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
23.1 What Are Species? The biological species concept : proposed by Ernst Mayr: Species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups .” This does not apply to asexually reproducing organisms.
Image of page 8
23.2 How Do New Species Arise? Allopatric speciation occurs when populations are separated by a physical barrier. Also called geographic speciation .
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern