Evolucija spolnog razmnožavanja

undergraduate thesis

• Title (english): Evolution of sexual reproduction
• Author: Damjana Levačić
• Mentor: Damjan Franjević (mentor)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2017-09-05, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Spolno razmnožavanje je način reprodukcije koje se uglavnom povezuje s eukariotima, a glavno obilježje mu je rekombinacija gena. U odnosu na nespolno razmnožavanje zahtijeva ulaganje veće količine energije pa je dugo nepoznanica bio razlog takve taktike razmnožavanja. Znanstvenici su došli mnogo bliže odgovoru na pitanje kada i zašto se spolno razmnožavanje razvilo. Smatra se da je takvo razmnožavanje poteklo od zajedničkog pretka svih eukariota starog oko 2 milijarde godina. Prema najistaknutijoj hipotezi spolno razmnožavanje ubrzava evoluciju. Miješanje vlastitog genskog materijala i kombiniranje njegovog djela s genskim materijalom drugog člana iste vrste omogućuje relativno brz nastanak novog genoma s moguće korisnim mutacijama. Pretpostavlja se da su eukarioti koji se razmnožavaju nespolno potekli od predaka sa spolnim razmnožavanjem, s obzirom da je i kod njih pronađena većina gena potrebnih za mejozu. Što su vrste s vremenom postajale odvedenije, napredovali su i njihovi mehanizmi povezani s razmnožavanjem. Spolni kromosomi su evoluirali zasebno više puta, a ustalili su se kod većine eukariota s odvojenim spolovima. Oblik prirodnog odabiranja kojeg proživljavaju sve vrste sa spolnim načinom razmnožavanja je spolna selekcija i o njoj ovisi hoće li jedinka imati potomstvo i koliko će ga biti. Spolna selekcija obuhvaća niz procesa i događaja koji se zbivaju između i unutar mužjaka i ženke iste vrste. Mehanizmi povezani sa spolom i spolnim načinom razmnožavanja su kodirani određenim genima i njihovo razumijevanje je važno za razumijevanje šire slike moćne prirodne sile, evolucije.

Abstract (english)

Sexual reproduction is predominant type of reproduction which is mainly linked to eukaryotes and its main characteristic is recombination of genes. It requires significant costs relative to asexuality, so for a long-time reason for that kind of reproduction tactic was unknown. Scientists came much closer to answering questions like „When and why sexual reproduction has evolved? “. It is considered that sex first emerged in the common ancestor of all eukaryotes about 2 billion years ago. According to prominent hypothesis sex may speed up evolution. Shuffling their own DNA and combining some of it with the DNA of another member of the same species enables relatively quick production of new genome with possibly beneficial mutations. It is assumed that asexual eukaryotes evolved from sexual ancestors, considering their genome contains almost all the genes necessary for meiosis. As species evolved trough time, their reproduction mechanisms became more complex. Sex chromosomes have evolved independently many times in animals and plants, and held on to most eukaryotes with separate sexes. A form of natural selection that all sexual species go through is called sexual selection and it decides whether the individual will have offspring and how many there will be. Sexual selection includes many processes and events that happen in between and inside male and female of the same species. Mechanisms connected to sex and sexual form of reproduction, are coded by genes, and their understanding is important to recognize the bigger picture of powerful natural force, evolution.

• Keywords: spolno razmnožavanje
• Keywords (english): sexual reproduction
• Language: croatian
• URN:NBN: urn:nbn:hr:217:242420
• Study programme: Title: Ecology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) biologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) biologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-09-29 12:08:09