BIOL1002 Lecture Notes - Lecture 8: Gametogenesis, Parthenogenesis, Crustacean

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magentasnake323

6 Nov 2018

School

University of Newcastle

Department

Biological Sciences

Course

BIOL1002

Professor

Liz Burne

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Document Summary

Three main mechanisms of asexual reproduction: budding: offspring forms within or on a parent, fission: individuals split in two, parthenogenesis: females produce eggs that develop without fertilisation. Diploid not haploid cells as involves the process of mitosis not meisos. Important to remember that there is no change between offspring and parents in asexual reproduction. Many species can switch between reproducing sexually and asexually. Daphnia (a crustacean) reproduces both sexually and asexually in a given year: Spring and summer: female offspring are produced by parthenogenesis. Autumn and winter: males produced and females and males produce gametes for sexual reproduction. Daphnia appear to switch to sexual reproduction when conditions deteriorate. Crossing over during meiosis i helps to generate genetic diversity. During sexual reproduction haploid gametes produced by meiosis undergo fertilisation to produce a diploid zygote. Steroid hormones synthesised in the gonads (testes and ovaries) - can enter the nucleus and alter gene expression.

Related Questions

there could be more than one answer or no answer at all

1. _____ Females that reproduce sexually versus asexually are said to incur a âtwo-fold cost of sexual reproduction.â Which of the following costs are associated with sexual reproduction for females?

A) MALES! That do-nothing lot really does not directly contribute offspring to the next generation. Females would be better off making all daughters.

B) FEMALES! In most natural settings, those daughters compete with their mothers for potential mates and resources needed to successfully reproduce.

C) MITOSIS! Since sexual reproduction can produce many more offspring than asexual reproduction, there are energetic costs associated with the mitotic divisions required to produce those offspring.

D) MEIOSIS! Every time a gamete is produced, the parent loses a little bit of itself. Half to be precise since only half of its genes are passed on to sexually produced offspring.

E) DIVERSITY! Mothers maximize fitness if all offspring are genetically just like them. Sexual reproduction causes genetic diversity, which ultimately lowers the fitness of both parents.

Just to keep you in practice, a couple of the much beloved multiple multiple choiceâ¦

1. An increase in CO₂ levels in the blood directly or indirectly causes which of the following?

A) an increases in ventilation rate

B) a decrease in the pH

C) a decrease in hemogloginâs binding affinity for O₂

D) a decrease in the O₂ levels in the blood

E) an immediate increase in the number of red blood cells found in the blood stream

2. _____ Females that reproduce sexually versus asexually are said to incur a âtwo-fold cost of sexual reproduction.â Which of the following costs are associated with sexual reproduction for females?

A) MALES! That do-nothing lot really does not directly contribute offspring to the next generation. Females would be better off making all daughters.

B) FEMALES! In most natural settings, those daughters compete with their mothers for potential mates and resources needed to successfully reproduce.

C) MITOSIS! Since sexual reproduction can produce many more offspring than asexual reproduction, there are energetic costs associated with the mitotic divisions required to produce those offspring.

D) MEIOSIS! Every time a gamete is produced, the parent loses a little bit of itself. Half to be precise since only half of its genes are passed on to sexually produced offspring.

E) DIVERSITY! Mothers maximize fitness if all offspring are genetically just like them. Sexual reproduction causes genetic diversity, which ultimately lowers the fitness of both parents.

Question 1 (2 points)

In which phase of cell division is marked by the dissolution of the nuclear membrane, the condensation of chromosomes, and the formation of the mitotic spindle?

Question 1 options:

	prophase
	metaphase
	telophase
	anaphase

Question 2 (2 points)

The physical separation of cells during cell division is called:

Question 2 options:

	Cytokinesis
	Telophase
	Interphase
	Chromosome
	Cell plate

Question 3 (2 points)

Meiosis is necessary for sexual reproduction; the gametes formed during this process before fertilization are _______________.

Question 3 options:

	Haploid
	Diploid
	Zygote
	Homologous
	Tetrads

Question 4 (2 points)

Mitosis is the process by which a ___________ cell separates the chromosomes in its nucleus into two identical sets of nuclei.

Question 4 options:

	eukaryotic
	prokaryotic
	bacterial
	all of these are correct

Question 5 (2 points)

Which of the following statements about crossing over is INCORRECT?

Question 5 options:

	It occurs between homologous chromosomes
	It allows for two parents to produce many different types of offspring
	It contributes to genetic diversity in a population
	It occurs during prophase I of mitosis

BIOL1002 Lecture Notes - Lecture 8: Gametogenesis, Parthenogenesis, Crustacean

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