Zimmer, C. 2014. Chapter 6 - The Ways of Change: Drift and Selection, in The Tangled Bank: An Introduction to Evolution. Roberts and Company Publish

Reading:

Zimmer, C. 2014. Chapter 6 - The Ways of Change: Drift and Selection, in The Tangled Bank: An Introduction to Evolution. Roberts and Company Publishers, Co.

Background

This week we continue our exploration of the processes of evolution with Carl Zimmer.

In the previous tutorial we explored the ecological mechanisms that might lead to reproductive isolation and ultimately the evolution of new species, in an evolutionary process termed speciation. This week we explore the genetic processes by which the changes in anatomy, physiology and behaviour that result in reproductive isolation, occur.

Although genes were unknown at the time that he published On the Origin of Species in 1859, it was clear to Darwin that offspring inherited traits from their parents. This heritability of (successful) traits is one of the requirements of Natural Selection. The simple premise of this idea is that genetic traits are passed from parent to offspring, and that some traits are more successful than others, as measured by greater reproductive success of those individuals. This biased reproductive success results in these successful traits becoming more dominant in that population over time, leading to a progressive change in the genotype of the population and consequent changes in morphology, behaviour and physiology. Eventually these changes are sufficient to result in reproductive isolation as discussed in last weeks tutorial exercise, and the rise of new species.

4815191880596A portrait of Charles Darwin shortly after his return from the voyage of The Beagle, in the late 1830s.

020000A portrait of Charles Darwin shortly after his return from the voyage of The Beagle, in the late 1830s.

"There is grandeur in this view of life, with its several powers, having been originally breathed, into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning, endless forms, most beautiful and most wonderful, have been and are being, evolved."On the Origin of Species(1859)

Critical Vocabulary encountered in Zimmer Reading: Please define these terms in the CONTEXT of this article. Some of these definitions are more difficult you get double points for those (**).

VOCABULARY DEFINITION AND EXPLANATIONS PEER CHECK AND SELF ASSESSMENT

1 Allele /1

2 Mutation /1

3 Fitness /1

4 Genetic fixation /1

5 Founder effect /1

6 Genetic drift** /2

7 Hardy-Weinberg equilibrium** /2

8 Natural selection** /2

9 Heterozygous** /2

10 Success fitness** /2

SCI102 Points Total

/15

Reading Comprehension and Critical thinking

Background

The questions below are designed as discussion points to be worked on with your peers during your tutorial class. You will need to be able to refer to all of the readings nominated for this weeks tutorial exercises, so make sure you bring them with you. It is important that you talk about these questions and that any unclear points are resolved in the tutorial. Write down your answers resulting from your tute group discussion, as these questions may come up in your final exam.

If you've anything in doubt, talk to your tutor, show your work to your tutor and get feedback.

Describe and define the population-level consequences of the three types of selection identified by Zimmer;

Directional selection (50 words)

Stabilising selection (50 words)

Disruptive selection (50 words)

Zimmer states (p 135) that, In a small population, it (natural selection) is opposed by strong genetic drift, which can eliminate beneficial mutations. Explain the rationale behind this statement (75-100 words).

Zimmer identifies two lessons regarding evolution (p 146), resulting from the Grants work on finches on Daphne Major. List these two lessons, and the evidence for these (150-250 words).

Birds of Australia: A Photographic Guide by Cambell et al. (2014)

Revision notes for SCI102 Biodiversity and Ecology

Week 5 Assoc Prof Alison Shapcott

The evolution and diversity of land plants: Gymnosperms and Angiosperms

Ch 20 Campbell Biology Text book

These revisions notes are designed to assist you to study for quizzes and exams. The information comes from the lecture week 5 and laboratory notes for the week 6 Gymnosperms and Angiosperms and the ch 20 of Campbell Biology Text book. You will find that doing the questions and exercises at the end of ch 20 in addition to these below will be very helpful for your understanding and revision.

Terms you should know and understand

Tracheid

Sporophyl

Microsprangium

Microsprores

Megasporangium

Ovuliferous scale

Megaspore

Pollen drop

Vessel elements

Monocots

Eudicots

Stamen

Anther

Style

Stigma

Carpel

Questions you should be able to answer

1.What do the vascular systems of ferns and Gymnosperms have in common?

2. What makes the Ginkgo and Cycads distinct from other Gymnosperms?

3.What were the earliest Gymnosperms?

4. Which orders of Gymnosperms are in the Pinophyta?

5. Which order of Gymnosperms are found naturally in Australia?

6. Are Gymnosperm male cones haploid or diploid?

7.In Gymnosperms are male microspores produced by mitosis or meiosis??

8.Where does meiosis take place in female Gymnosperm cones?

9. Draw a labelled diagram showing the life cycle of a typical pine tree?

10. How is pollen dispersed in most gymnosperms?

11.What makes angiosperm vascular tissue distinct from gymnosperm vascular tissue?

12. What are the basal or early branching angiosperms? Can you give an example?

13. What are the three main orders in the magnoliid clade of Angiosperms? Can you give some examples from these?

14. What are some of the key anatomical differences between Monocots and Eudicots?.

15. What are the two major groups of Eudicots?

16. Draw a labelled diagram to represent the structure of an Angiosperm flower?

17. Is Angiosperm pollen haploid or diploid?

18. Draw a labelled diagram to represent the life cycle of an Angiosperm that shows what stages are haploid and which are diploid

19. Summarise some of the key adaptations that enabled seed plants to diversity on land.