b13 - Chapter 13 Meiosis and Sexual Life Cycles Lecture...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 13 Meiosis and Sexual Life Cycles Lecture Outline Slide 4: Overview The Basis of heredity: Hallmark of Living organisms able to reproduce their own kind. Offspring resemble their parents more than they do less closely related individuals of the same species. The transmission of traits from one generation to the next is called heredity or inheritance. We will spend some time discussing the sexual vs. asexual reproduction – important to understand the origins of genetic variability Meiosis: reductional division that produces haploid gametes from diplod progenitors. The mechanism of meiosis – how this produces haploid gametes from diploids Origins of Genetic variation How meiosis impacts heredity, how it introduced variability SLIDE 5 - human family This family provides a visual example of three important features of living organisms : 1.) reproduce their own “kind”. 2.)In addition, offspring resemble their parents more closely than unrelated individuals of the same species. TRAITS are passes through generations – a process called INHERITANCE or HEREDITY IG Lecture Outline 13- 1
Background image of page 1

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

View Full DocumentRight Arrow Icon
3.) However, note also that offspring differ somewhat from parents – they are not clones of their parents. In addition, offspring are not (usually) identical to one another. This is a demonstration of genetic variability! Realize that the genetic make up present in the offspring had to come from the parent s – however, somehow the process of sexual reproduction has produced offspring with slightly different genetic make up than any single parent . SLIDE 6 – dogs This ‘variation’ has been exploited by farmers and animal breeders who have bred plants and animals for desired traits for thousands of years. Take a look at these dogs – these three breeds are highly specialized with extraordinary morphological diversity. However – all three are dogs – the same species – and are quite capable of interbreeding. Somewhere along the line – dogs with obvious variability were intermated and specific TRAITS were selected for and these became homogeneous within the breed. The important fact is that the variability existed within the species (arose through mutation) to enable such artificial selection. INCREASING VARIABILITY IS ONE HALMARK OF SEXUAL REPRODUCTION!! SLIDE 7 - Teoscinte and corn – maize domesticated from teoscinte 10,000 years ago through the process of selecting for better ear (easy to eat, high starch etc). The mechanisms of heredity and variation eluded biologists until the development of genetics in the 20th century. SLIDE 8 Genetics is the scientific study of heredity and variation. We know recognize that: Units of heredity = genes Genes are encoded by DNA – Genetic information is transmitted as specific sequences of the four deoxyribonucleotides in DNA organized into chromosomes. Most
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/12/2011 for the course BSC 2010 taught by Professor Bowes during the Spring '08 term at University of Florida.

Page1 / 17

b13 - Chapter 13 Meiosis and Sexual Life Cycles Lecture...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online