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Biology

A Local Ecosystem

New Revised Edition

Kerri Humphreys

© Science Press 2014First published 2004Revised Edition 2014

Science PressBag 7023 Marrickville NSW 1475 AustraliaTel: (02) 9516 1122 Fax: (02) 9550 [email protected]

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of Science Press. ABN 98 000 073 861

ContentsUse the table of contents to record your progress through this book. As you complete each topic, write the date completed, then tick one of the three remaining columns to guide your revision for later. The column headers use the following codes:

?? = Don’t understand this very well at all. RR = Need to revise this. OK = Know this.

Topic Page Date done ?? RR OK Topic Page Date

done ?? RR OK

Introduction 1 30 Commensalism 41 Verbs To Watch 1 31 Allelopathy 421 Assumed Knowledge 2 32 Disease 432 The Biosphere 3 33 Decomposers 453 Diversity of Australian Ecosystems 4 34 Food Chains and Food Webs 464 Abiotic and Biotic Features of the

Environment5 35 Play – Inside a Food Web 48

5 Abiotic Features of Aquatic Environments

7 36 Practice with Food Webs 52

6 Australia and Abiotic Characteristics 8 37 Field Study – A Food Web in a Rock Pool

53

7 Field Study – Abiotic Features 9 38 Energy Pyramids 558 Distribution and Abundance 11 39 Biomass Pyramids 569 Distribution and Climate 13 40 The Open Ocean Food Web and

Ecological Pyramids58

10 Distribution Variations 15 41 Adaptations 5911 Sampling Techniques – Transects 16 42 Habitats 6112 Field Study – Transects 17 43 Ecological Niches 6213 Sampling Techniques – Quadrats 19 44 Field Study – Organisms on a Rock

Platform63

14 Activity – A Quadrat Study 20 45 Mangrove Ecosystems 6515 Field Study – Abundance Using

Random Quadrats22 46 Australian Rainforest Ecosystems 67

16 Sampling Techniques – Percentage Cover

23 47 Australian Woodland Ecosystems 68

17 Field Study – Percentage Cover 24 48 Succession 6918 Sampling Animal Populations 25 49 Human Activities – Introduced Species 7119 Experiment – Capture-mark-recapture 27 50 The Introduced Cane Toad 7320 Respiration 28 51 Human Activities 7521 Photosynthesis 29 – Use of Pesticides

22 Respiration, Photosynthesis and the Carbon Cycle

30 52 Biomagnification 76

23 Uses of Energy by Organisms 32 53 Pollution 7724 Population Ecology 34 54 Strategies to Balance Human Activities 7825 Trends in Population Estimates 35 55 Field Study – Human Impact 8026 Predator-Prey Populations 36 56 Writing a Practical Report 8227 Competition for Resources 37 Topic Test 8428 Mutualism 38 Answers 8729 Parasitism 40 Index 111

1 A Local EcosystemScience Press

Surfing Biology

Introduction

Each book in the Surfing series contains a summary, with occasional more detailed sections, of all the mandatory sections of the syllabus, along with questions and answers.

It is envisaged this book will be useful in class for both initial understanding and revision, while the more traditional textbook can remain at home for more detailed analysis.

All types of questions – multiple choice, short response, structured response and free response – are provided. Questions are written in exam style so that you will become familiar with the concepts of the topic and answering questions in the required way.

Answers to all questions are included.

A topic test at the end of the book contains an extensive set of summary questions, including multiple choice and free response questions. These cover every aspect of the topic, and are useful for revision and exam practice. Marking guidelines are supplied where appropriate.

Verbs To Watch

account, State reasons for, report on, giveaccount for an account of, narrate a series of

events or transactions.analyse Identify components and the

relationships among them, draw out and relate implications.

apply Use, utilise, employ in a particular situation.

appreciate Make a judgement about the value of something.

assess Make a judgement of value, quality, outcomes, results or size.

calculate Determinefromgivenfacts,figuresor information.

clarify Make clear or plain.classify Arrange into classes, groups or

categories.compare Show how things are similar or

different.construct Make, build, put together items or

arguments.

contrast Show how things are different or opposite.

critically Add a degree or level of (analyse/evaluate) accuracy, depth, knowledge and

understanding, logic, questioning, reflectionandqualitytoananalysisor evaluation.

deduce Draw conclusions.define State the meaning of and identify

essential qualities.demonstrate Show by example.describe Provide characteristics and

features.discuss Identify issues and provide points

for and against.distinguish Recognise or note/indicate as being

distinct or different from, note difference between things.

evaluate Make a judgement based on criteria.

examine Inquire into.explain Relate cause and effect, make

the relationship between things evident, provide why and/or how.

extract Choose relevant and/or appropriate details.

extrapolate Infer from what is known.identify Recognise and name.interpret Draw meaning from.investigate Plan, inquire into and draw

conclusions about.justify Support an argument or conclusion.outline Sketch in general terms; indicate

the main features.predict Suggest what may happen based on

available information.propose Put forward (a point of view, idea,

argument, suggestion etc.) for consideration or action.

recall Present remembered ideas, facts or experiences.

recommend Provide reasons in favour.recount Retell a series of events.summarise Express concisely the relevant

details.synthesise Put together various elements to

make a whole.

2Science Press

Surfing BiologyA Local Ecosystem

1 Assumed Knowledge

1. Defineecosystem.2. Distinguish between biotic and abiotic features of

the environment.3. Describe the importance of cycles of materials in

ecosystems.4. Describe some impacts of human activities on

ecosystems.5. Discuss one strategy used to balance human

activities and needs in ecosystems with conserving, protecting and maintaining the quality of the environment.

6. Figure 1.1 shows the relationships between the environment and organisms.

Atmosphere

Hydrosphere

Lithosphere

O2CO2

H2O

H2O

Minerals

Figure 1.1 Organisms and the environment.

(a) Defineenvironment.(b) What is the biosphere, hydrosphere and

lithosphere?7. Defineadaptation.8. Use an example to show how a named adaptation

assistsinaspecificenvironment.9. Defineproducer,consumeranddecomposer.10. Use a food chain to show how producers, consumers

and decomposers are related.11. Definephotosynthesisandrespiration.12 Describe the roles of photosynthesis and respiration

in ecosystems.

Colonial green algae

Diatom

Filamentous blue-green algae

Filamentous green algae

Rotifer Water-flea Cyclops

Unicellular green algae

Figure 1.2 Plankton.

13. Figure 1.2 shows plankton. (a) What is plankton? (b) What is the difference between

phytoplankton and zooplankton?14. What is the difference between diurnal and nocturnal

behaviour?15. For plants, what is the difference between deciduous and

evergreen? Give an example of each.16. Definebiodiversity.17. What is meant by a feral species? Give an Australian

example. 18. (a) What is a food chain? (b) Draw a food chain containing four organisms.19. How does a food web differ from a food chain?20. What is a eucalypt?

Eucalyptus piperita (Sydney peppermint) Eucalyptus pilularis (blackbutt)

2 m

Smooth,pale barkon upperbranches

Untidyshreds

Leaves paleunderneath

Whiteflower

2 m

Barkhangingin strips

Irregular veins

Roughgreybark

Bareupperbranches

Whiteflower

Fruit

Figure 1.3 Two eucalypts of the Sydney region.

21. Figure 1.4 shows how habitats vary from the pole to the equator as well as from sea level to the top of tall mountains.

(a) Use this diagram to list the changes in habitat from the pole to the equator.

(b) Compare the change in habitat as you move from the equator to the poles with the change in habitat as you move from sea level to the top of a high mountain.

Figure 1.4 Changes in habitat with altitude and latitude.

Low,shrubbygrowths,lichens

Snow,ice

TropicalTemperateTundraPolar

Grassland,deciduous,

forest

Coniferousforest

Rainforest,desert

grassland

Grassland,

deciduous

forest

Coniferous

forest

Low, shrubby

growths,

lichens

Snow,

ice

Increasing latitude Incre

asing

altitu

de


Surfing Biology

2 The Biosphere

The biosphere is the total of all areas where living things are found, i.e. the sum of all ecosystems. The biosphere extends from the equator to the polar caps. Since the discovery of microbes deep in the Earth’s crust, in the upper layers of the atmosphere and deep in oceanic trenches, it is hard to estimate the thickness of the Earth’s biosphere.

Water

OxygenCarbon dioxide Atmosphere

Lithosphere

Pedosphere

Hydrosphere

Figure 2.1 Interaction of biosphere, lithosphere, hydrosphere and atmosphere at pedosphere.

Processes and interactions occur between the biosphere, hydrosphere lithosphere and atmosphere. Living things interact with the non-living things in their environment – they use air, water, soils and sediments in their daily struggle for survival. The lithosphere is the outer, rigid solid shell of rock on Earth consisting of the crust and part of the upper mantle. The hydrosphere is the combined mass of water found on, under and over the surface of the Earth. It includes the water in oceans, rivers and lakes and the water in the air.

The atmosphere is the body of air surrounding the planet. The pedosphere is the outermost layer of the Earth where the lithosphere, hydrosphere, atmosphere and biosphere interact to form soil. It is the sum total of all organisms, rock, air and water interacting in a dynamic way to form soil.

The biosphere has three important functions:

• It converts energy from either the Sun or chemical sources to organic material.

• It harvests essential elements and minerals from the atmosphere, hydrosphere and lithosphere to maintain life.

• It responds to changes by altering food webs when geological, cosmic or dynamic Earth movements occur.

A biomeisalargegeographicalareathathasaspecificclimate and sustains distinctive communities of plants and animals and can be any of the world’s major ecosystems, e.g. tundra, desert, grassland, desert and tropical rainforest.

QUESTIONS1. Define biosphere.2. What is the difference between the lithosphere, the

hydrosphere and the atmosphere?3. Definepedosphere.4. Outline the three important functions of the

biosphere.5. Definebiome.6. Name three biomes found in Australia.7. Which biomes would you expect to have the

following conditions? (a) Dry and cold. (c) Dry and hot. (b) Wet and hot. (d) Fairly dry and warm.

Figure 2.2 Major biomes of the world.

Major biomes of the world

80o

40o

60o

20o

40o

0o

20o

80o

60o

80o

40o

60o

20o

40o

0o

20o

80o

60o

Key

Temperate rainforest

Tropical rainforest

Desert

Grassland

Scrub forest

Temperate deciduous forest

Coniferous forest

Tundra

75o90o 15o 0o135o165o 45o105o 90o60o 135o 165o45o 105o

16Science Press


11 Sampling Techniques – Transects

Sampling is a range of techniques used to estimate population numbers when total counts cannot be made. A total count can be used in some situations, e.g. aerial surveys can estimate kangaroo populations.

A transect isaline,striporprofileforcountingandmapping the number of individuals at different distances along the line. Transects are often used to show how the diversity of species changes across an area, e.g. when an area changes from grassland to woodland to forest. Transects often include a vertical scale to show not only the height of the plants but any change in topography such as valleys or mountains.

A line transect uses a rope or tape measure and the species along the line are recorded. The line can be a random line or follow an environmental gradient, e.g. across a sand dune succession. Continuous sampling can occur along the line or point sampling can occur at measured intervals. Line transects tend to be time efficientandsuitedtostudyingplantsandimmobileoreasily caught animals. If a species is only found in a specialised area or has low numbers in the area then a line transect may miss this species and the species will not be recorded in the area.

Line transect Belt transect

1 metre

Figure 11.1 Line transect and belt transect.

A belt transect is a measured strip across the area and can also be a random belt or follow an environmental gradient, e.g. altitude and latitude. The width of the belt will vary depending on the organisms being studied. Sampling can be continuous along the transect or quadrats canbeplacedatspecifieddistancesalongthetransectand individuals counted in these quadrats. Belt transects are useful when studying the seashore, grasslands and woodlands. Belt transects are time consuming and suited for studying plants and immobile animals or easily caught animals. Interrupted belt transect sampling can miss some species if they are present in low numbers. It is important to minimise disturbance to the environment while collecting the data about all organisms in each quadrat.

Continuousbelt transect

Interruptedbelt transect

Figure 11.2 Continuous and interrupted belt transect.

QUESTIONS1. Definesampling.2. Explain why sampling techniques are needed.3. Defineatransect.4. What is the difference between a line transect and a

belt transect?5. Figure 11.3 shows a transect up the side of a mountain.

Snow and ice

Alpine meadow

Coniferous forest

Deciduous forest

Rainforest

Alti

tude

Figure 11.3 Transect across a mountain.

(a) Outline how vegetation changes as you go up a mountain.

(b) Identify two abiotic factors which would contribute to the change in vegetation along this transect.

6. The diagram in Figure 11.4 was made by a biology studentcarryingoutatransectfieldstudyatschool.

1

3

Metres

5

7

8642Wall oflaboratory

block

16141210 2018 2422 26Metres

TreePavementLow shrubGrassKey:

Figure 11.4 Student transect of school grounds.

Where is the grassed area in the grounds of this school?

32Science Press


23 Uses of Energy by Organisms

Energy can take many forms, e.g. kinetic (moving) energy, potential energy, light, electricity, mechanical, chemical. Accordingtothefirstlawofthermodynamics,energycanneither be destroyed nor created; rather, it is converted from one form into another.

The energy source for animals comes from their food supply, e.g. herbivores eat plants and their energy comes from breaking down the complex organic molecules in plants.

In cells, the energy released in respiration comes from the carbon bonds in food molecules. If a cell is not givensufficientexternalfood,itwilluseanyorganiccompound as the fuel source for respiration, i.e. it will use any carbohydrate, fat, protein, nucleotide, or vitamin within the cell. The energy released can then be used for mechanical work, e.g. contraction of muscle cells and the beating of cilia, transport work, e.g. pumping substances across membranes or chemical work, e.g. synthesis reactions.

Table 23.1 Uses of energy by organisms.

Use Description

Body temperature Energy released as heat is used to help maintain body temperature, e.g. endotherms – birds and mammals.

Synthesis Chemical reactions that form large complex molecules, e.g. proteins, lipids and fats require an input of energy.

Growth Growth requires more cells. Energy is needed for cell division, cell elongation and cell differentiation.

Active Transport The movement of some substances across cell membranes requires an input of energy, e.g. animal cells actively pump sodium out of the cell and potassium into a cell.

Repair and maintenance

Old or damaged cells need to be repaired or replaced.

Transport Energy is required to move some substances internally, e.g. movement in the phloem of plants and circulatory system of animals.

Functioning of specialised cells

Some specialised cells require an input of energy for optimal functioning, e.g. nerve cells, muscle cells, liver cells and kidney cells in mammals.

Heat is needed by the body for reactions as the enzymes in the body require an optimum temperature for maximumefficiency.Atlowtemperatures,therandommovement of molecules decreases, reducing their chance of bumping into each other and hence having a reaction.

Maintaining bodytemperature

Energy

Synthesis ofpolysaccharides

Synthesisof fats

Repair

Cell maintenance

Active transport

Growth

Figure 23.1 Uses of energy by organisms.

The energy released by respiration can be used by the organism in several different ways. Some of the energy is released as heat and this is used to maintain body temperature. This is especially important for endotherms (warm-blooded animals that generate heat by internal mechanisms). If a human gets cold, muscles will start to ‘shiver’ – this is their way of increasing activity, respiring at a higher rate and releasing heat for the body. Heat is needed by the body for reactions as the enzymes in the body require an optimum temperature for maximum efficiency.

The released energy can be used to cause other chemical reactions in cells to occur. For example, it can cause the synthesis of complex molecules from simple compounds, e.g. the formation of polysaccharides from simple sugars, the formation of polypeptides and proteins from amino acids, or the formation of fats from fatty acids and glycerol.

The released energy can also be used by cells for growth, repair of damaged or old cells, or for active transport of materials across cell membranes.

The ATP-ADP cycleEnergy in cells in carried in the form of ATP, adenosine triphosphate. ATP consists of adenosine with three phosphates one of which is held by an unstable, high-energy bond. When the third phosphate is detached, energy is released and the molecule becomes adenosine diphosphate. Working cells are constantly using ATP as their source of energy. The reaction is reversible, which means catabolic reactions in the cell (reactions that break down complex molecules to simple molecules and release energy) such as respiration cause the formation of ATP from ADP.


Surfing Biology

Then anabolic reactions (reactions that synthesise complex molecules from simpler compounds) use the energy of ATP which reverts back to ADP. In aerobic respiration 1 glucose molecule is broken down and 38 ATP molecules are formed.

ATP

ADP

Energy fromcellularrespiration

Energy used insynthesis of protein,fat, carbohydrate,DNA, RNA

+P –P

ATP-ADP cycle

Figure 23.2 The ATP/ADP cycle.

QUESTIONS1. List some forms of energy.2. Statethefirstlawofthermodynamics.3. Identify the energy source for herbivores and

carnivores.4. Name the process that releases energy for use in

cells.5. What is an endotherm?6. Explain why humans ‘shiver’ when cold.7. Identify four uses of energy used by organisms.8. Identify some synthesis reactions that occur in cells.9. Outline why reaction rates are slower at lower

temperatures.10. What is the main form of energy in cells?11. Distinguish between catabolic reactions and anabolic

reactions.12. Write a generalised equation for the ADP-ATP

reactions.13. How much energy is produced during aerobic

respiration?14. Some organisms, e.g. some yeasts and many bacteria

are anaerobes and can live in environments that do not have free oxygen. They gain energy through anaerobic respiration and fermentation. During fermentation one molecule of glucose produces 2 molecules of ATP. Discuss why this chemical pathway would not meet the needs of multicellular animals such as humans.

15. Which of the following is not a use of energy by organisms?

(A) Synthesis of complex organic compounds. (B) Diffusion across membranes. (C) Growth of new cells. (D) Repair of damaged cells.

16. Which of the following organisms would most heavily rely on energy from respiration for maintenance of body temperature?

(A) Red kangaroo. (B) Frill-necked lizard. (C) Blowfly. (D) Red-bellied black snake.17. Whatwillhappenifinsufficientexternalfoodis

taken into a cell? (A) The cell will start to make its own food. (B) It will engulf a nearby neighbouring cell. (C) It will use other organic compounds within the

cell as a fuel source. (D) Respiration becomes anaerobic.18. The energy released by respiration is often used

for maintenance of body temperature. Which of the following will occur if body temperature was lowered?

(A) Chemical reactions will speed up. (B) Chemical reactions will slow down. (C) Enzymes will break down. (D) Random movement of molecules will increase.19. What is the important product of respiration for

cells? (A) CO2

(B) Glucose (C) ADP (D) ATP20. Figure 23.3 shows a sequence of events that occur in

plants.

Sunlight

Glucose

ATP

X

Y

Figure 23.3 A sequence of events in plants.

What are processes X and Y?Process X Process Y

(A) Respiration Respiration(B) Photosynthesis Transpiration(C) Photosynthesis Respiration(D) Respiration Photosynthesis

21. Which of the following involves a catabolic reaction?

(A) Respiration. (B) Protein synthesis. (C) Active transport of substances across a

membrane. (D) Production of complex lipids.


Surfing Biology

32 Disease

A disease is any condition that impairs or interferes with the normal functioning of the body. A pathogen is a disease-causing parasite that lives on or in a host. They can be microscopic or macroscopic and are found in air, water, soil and any contaminated articles. An infectious disease is caused by pathogens which invade the body. Infectious diseases are contagious and can be passed from one host to another. Transfer from one host to another can be by direct or indirect contact.

Many micro-organisms cause disease, e.g. viruses, bacteria, protozoans, fungi and algae. Since viruses can only reproduce inside a host cell, all viruses are potentially pathogens. Infection occurs when a pathogen is present in a host. A pathogen may infect a host but the host may not develop the disease as they do not show symptoms and do not have an impairment of body functions.

Viruses

Viruses are very small (approximately 30 to 300 nm) and reproduce by taking over a host cell. All, except for a very few such as the smallpox virus, can only be seen under an electron microscope. Viruses are not cellular and contain nucleic acid – either RNA or DNA. They are surrounded by one or more coats of protein and can be crystallised.

Papillomavirus T-evenbacteriophage

Simplexvirus(herpes simplexvirus 1 and 2)

Lentivirus(HIV)

Hepadnavirus(hepatitis B virus)

Influenzavirus(influenza viruses

A and B)

Lyssavirus(rabies virus)

Orthopoxvirus(vaccinia virus)

Figure 32.1 Viruses.

There are many viral diseases for both plants and animals. Human viral diseases include measles, rubella, chickenpox, AIDSandpoliomyelitis.Influenzaisaviraldiseaseofhumansandotheranimals,e.g.avianinfluenza(birdflu)andH1N1(swineflu)andsomecancrossspeciesbarriers.TherabbitprobleminAustraliawasfirstcontrolledbythe myxoma virus causing the disease myxomatosis and biological control now uses the rabbit calicivirus causing the rabbit calicivirus disease (RCD). Rabies is a fatal viral disease that affects endotherms, e.g. humans, dogs, bats, rabbits and cats. Quarantine measures in Australia keep the continent rabies-free protecting native species, domestic pets and stock animals.

Plant viruses will cause stunted growth, the formation of galls, excessive branching and often produce a yellow mottling or spotting. This mosaic pattern is seen with tobacco mosaic virus, tomato mosaic virus and cucumber mosaic virus. The striped pattern of some tulips is caused by a viral infection. Insects, e.g. leafhoppers, aphids, nematode worms and fungi are vectors for these viruses transferring the pathogen from one host to another. Viruses affecting crops, e.g. rice, barley, potatoes, apples, peaches can cause extensive damage and dramatically reduce yield.

BacteriaBacteria are prokaryotes (no membrane-bound organelles) typically ranging in size from 0.5 to 5.0 micrometres in length with a single strand of DNA. Bacteria are named according to their shape – coccus (round), bacillus (rod) or spirochaete (spiral). Many bacteria have a capsule surrounding the cell wall.Thecapsuleaidspathogenicbacteriamakingitdifficultfor the host’s immune system to capture and break down the bacterium. If the capsule is removed the bacteria becomes more vulnerable to attack.

SaprotrophicMicrococci

(single cells)

Staphylococci(arranged in clusters;

cause blood poisoning)

Bacilli (single cells; causetuberculosis)

Bacilli (arrangedin chains;

cause dysentery)

Streptococci(arranged in chains;cause scarlet fever)

Vibrio(spiral-shaped;cause cholera)

Spirilla(spiral-shaped;cause syphilis)

Bacilli(with flagella;

cause typhoid)

Figure 32.2 Bacteria named by their shape.

There are many bacterial diseases for both plants and animals. Human bacterial diseases include bubonic plague, diphtheria, typhoid, Salmonella food poisoning, whooping cough, gonorrhoea, tuberculosis, pneumonia and certain skin infections, e.g. spots and boils. Bacterial diseases of animals include jaw disease of macropod marsupials, Chlamydia in koalas and birds and beak and feather disease in Australian birds.

Plant bacterial diseases include blights, soft rots and wilts and can be some of the most destructive diseases to plants. Fire blight in apples and pears damages fruit, stunts growth, reduces yield and can kill young plants in a single season. Bacterial vascular wilts mainly affect herbaceous plants, e.g. bacterial wilt of alfalfa and bean plants.


Surfing Biology

41 Adaptations

An adaptation is any feature or characteristic which helps the organism survive in its environment. Adaptationscanbeclassifiedaseitherstructural,physiological or behavioural.

Structural adaptations are those concerned with the anatomy of the organism – the size, shape or appearance of its body or part of its body. For example, the many mammals which can survive desert conditions, such as the bilby and red kangaroo, have large ears. This structure increases the surface-to-volume ratio of the animal and the capillaries in the ear can easily lose heat and help cool the animal. In plants, leaf size is a structural adaptation to the amount of sunlight available. For example, in the lower levels in a rainforest the plants have very large leaves to capture as much light as possible, while in deserts the leaf size is much smaller to reduce absorption of radiant heat energy and restrict water loss.

Figure 41.1 Red kangaroo.

Physiological adaptations are those involved with the internal functioning of the body’s metabolism. After the birth of a red kangaroo, the joey crawls up the mother’s fur, into her pouch and immediately attaches itself to a nipple. While it is in the pouch the sucking stimulus prevents the reoccurrence of the mother’s fertility cycle. This is a physiological adaptation to prevent the birth of offspring when the mother is unable to look after it. Many plants become dormant through winter, e.g. deciduous trees like the oak, birch, chestnut and maple which were introduced into Australia by settlers who wanted gardens ‘like they had back home’. Dormancy is a physiological adaptation, changing the tree’s metabolism to survive the harsh winter conditions.

Behavioural adaptations are those concerned with how an organism behaves – how it moves around or acts. To avoid the heat of the midday Sun, the red kangaroo will dig a shallow bed into the cooler layers of soil, in the shade of whatever plants are available and rest until the cooler hours of the day when it will look for feeding

grasses. Bilbies dig spiral holes approximately 1 to 2 metres deep. The burrows provide protection against the Sun’s heat and the nocturnal bilbies will avoid the hot daytime Sun by staying in their burrows, only emerging at night to forage for food. Since plants do not move around like animals, they have fewer behavioural adaptations. TheflowerofsunflowerswillfollowthemovementoftheSun across the sky during the day while the leaves of the prayer plant Maranta close up at night.

Problems with inferring characteristics are adaptationsWhen studying organisms and relating the chances of survival to body structure, physiology and behaviour, ecologists are always wary of inferring every characteristic as a particular adaptation for a particular habitat. Just because a plant or animal is found in a location does not mean it has special adaptations to that environment. For example, many desert plants can grow in areas with higher rainfall and milder temperature changes; for instance, old man saltbush, Atriplex nummularia, can be planted in gardens, although it is usually displaced by other species unless humans give assistance.

QUESTIONS1. Defineadaptation.2. Identify the three types of adaptations.3. Use an example to show your understanding of

structural adaptations.4. Definephysiologicaladaptation.5. Describe a physiological adaptation of a named

animal.6. Definebehaviouraladaptation.7. Outline a behavioural adaptation of a plant.8. Figure 41.2 shows an echidna.

Tracks

Front footHind foot

Echidna spiny anteater

Black to browncoat with lighter

spines

Tiny eyes

Short legs with long,heavy claws on feet

Pointysnout

Tiny mouth withno teeth and a

long tongue

Figure 41.2 Echidna.

Choose three of the labelled structural features and describe the importance of each adaptation.

60Science Press


9. The red-bellied black snake, Pseudechlis porphyriacus, is black on top and its underside is a red or crimson. It is found in a wide variety of habitats although is usually found in moister areas, particularly near water as it eats frogs, snakes, lizards,birds,smallmammalsandsometimesfish.

Figure 41.3 Red-bellied black snake.

Inthelateafternoon,youwilloftenfindred-belliedblack snakes basking in the sun on the rocks near creek beds.

(a) Classify this type of adaptation. (b) Explain how this adaptation assists the red-

bellied black snake. 10. Rainforests only grow in areas that have high rainfall

and a narrow range of daily temperatures. The musky rat kangaroo, Hypsiprymnodon moschatus, is a small marsupial found in rainforests.

Figure 41.4 Musky rat kangaroo.

Themuskyratkangaroohasagreatfirsttoeonitshind legs, which is a possum-like feature showing the evolution of kangaroos from possum-like ancestors. The mobility of this great toe allows the musky rat kangaroo to climb along fallen branches and logs. Explain why it is unwise for ecologists to assume that the development of the great toe on the hindlegsisaspecificadaptationbythemuskyratkangaroo to climb over fallen logs and branches.

11. Gum trees, or eucalypts, are common in Australian forests and woodlands. Eucalypts, e.g. the river red gum, have vertical leaves with the photosynthetic tissue of palisade cells on both sides of the leaf. Suggest an adaptive advantage for vertically hanging leaves.

Figure 41.5 Eucalyptus camaldulensis, river red gum.

12. Old man saltbush has leaves which are covered by a thick waxy cuticle to reduce water loss and it is able to tolerate high levels of salt in the soil – hence its name ‘saltbush’.

Figure 41.6 Old man saltbush.

Whichofthefollowingcorrectlyidentifiestheseadaptations respectively?

(A) Physiological and behavioural. (B) Structural and physiological. (C) Physiological and structural. (D) Structural and behavioural.


Surfing Biology

Answers

1 Assumed Knowledge1. Ecosystem is the living and non-living components of a self-

containing system.2. Biotic features are the living features and abiotic are the non-

living features.3. Cycles of materials include the cycling of the elements carbon

and oxygen in the carbon/oxygen cycle, the nitrogen cycle, the phosphorus cycle etc. These cycles are important as the amount ofmatterisfiniteandmaterialsneedtoberecycledsothatneworganisms can grow and develop.

4. Human activities that affect ecosystems include introducing foreign species into an area, which can threaten native species by competition or predation; cutting down trees which removes habitats and food sources; damming rivers and thus changing riverflowpatterns,whichaffectswaterlevelsforthebreedingoffishandwadingbirds.Bycausingchangesinthedistributionand abundance of native species, humans have a great impact on ecosystemscausingsomespeciestoflourish,whileotherspeciesbecome extinct.

5. One strategy is the creation of national parks where native species are protected and the quality of the environment is maintained, but they also provide recreational areas for human activities. This strategy balances the need for conservation with the need of human activities.

6. (a) The environment is everything that surrounds an organism, including both the biotic and abiotic features.

(b) The biosphere is the areas of the world, including land, water and air, where living organisms are found. The hydrosphere is the areas of the world covered in water, e.g. oceans, lakes, rivers. The lithosphere is the areas of the world made of rocky substances, e.g. continents.

7. An adaptation is a characteristic which helps an organism survive in its environment.

8. The webbing between the toes of a frog is an adaptation for an aquatic environment to assist swimming in water.

9. A producer is an organism that can make organic compounds from inorganic raw materials. Consumers are organisms that need to use another living organism as a source of food. Decomposers are organisms that help break down dead bodies or wastes of other organisms, recycling nutrients to the soil.

10. Producer consumer decomposer11. Photosynthesis is a series of chemical reactions where carbon

dioxide combines with water to form complex carbohydrates. Respiration is a series of complex chemical reactions which releases energy from complex carbohydrates.

12. Photosynthesis and respiration are processes which cause the cycling of the carbon/oxygen cycle. The role of photosynthesis is to use radiant energy to convert carbon dioxide and water into glucose and oxygen. Most food chains begin with a producer that photosynthesises. The role of respiration is to release energy from carbohydrates for use by organisms for body processes.

13. (a) Plankton is a name given to the microscopic producers andconsumersthatfloatinwater.

(b) Phytoplankton is the producers, e.g. algae, diatoms, while zooplanktonistheconsumers,e.g.ciliates,flagellates,rotifers, tiny crustaceans.

14. Nocturnal behaviour means the organism is active at night while diurnal behaviour means that the organism is active during the daytime.

15. Deciduous plants lose their leaves in winter, e.g. oak, maple, while evergreens do not lose their leaves in winter, e.g. eucalypts.

16. Biodiversity refers to the range of species living in an environment.

17. Feral species means a domestic species that has gone wild, e.g. when people release domestic cats into the wild, for whatever reason, the cats become ‘feral’.

18. (a) A food chain shows the feeding relationship between different species. It shows how energy and matter is passed in an ecosystem.

(b) Wood termite skink currawong19. Food webs are different to food chains in that the food web

consists of many interconnecting and interacting food chains. Food webs are more complicated than food chains.

20. Eucalypts are ‘gum’ trees. They are trees with ‘capped fruit’. 21. (a) At the pole the habitat is snow and ice with little

vegetation; this changes to low shrubs and lichens, then coniferous forest, then grassland and deciduous forest and then rainforest, desert and grassland.

(b) As you go from the equator to the poles and from sea level up a high mountain there is a similar change in habitat. They both start with rainforest, desert, grassland and then change to deciduous forest, coniferous forest, low shrubs and lichen and then snow and ice. Differences would be shown from a careful study of individual species present rather than a broad category such as ‘deciduous forest’. Each area would have species unique to that area. There would also be abiotic differences relating to the differences in altitude, e.g. lower air pressure and less oxygen available at the top of high mountains.

2 The Biosphere1. The biosphere is the sum total of all areas including land, water

and air where livings things are found.2. The lithosphere is the outer, rigid solid shell of rock on Earth

consisting of the crust and part of the upper mantle. The hydrosphere is the combined mass of water found on, under and over the surface of the Earth. The atmosphere is the body of air surrounding the planet.

3. The pedosphere is the outermost layer of the Earth where the lithosphere, hydrosphere, atmosphere and biosphere interact to form soil.

4. The three functions of the biosphere are: 1. The biosphere converts energy from Sun/chemical sources to organic material. 2. Harvests elements and minerals essential for life from other spheres. 3. Responds to changes by adjusting food webs.

5. Abiomeisalargegeographicalareathathasaspecificclimateand sustains distinctive communities of plants and animals and can be any of the world’s major ecosystems.

6. Australian biomes include desert, grassland and temperate forest.

7. (a) Tundra is dry and cold. (b) Tropical rainforest is wet and hot. (c) Desert is dry and hot. (d) Grassland is fairly dry and warm.

3 Diversity of Australian Ecosystems1. Ecosystem diversity refers to the variety of ecosystems on Earth. 2. When studying ecosystem diversity the variety of ecosystems

is studied as well as the range of communities in each area, the range of habitats and the ecological processes that occur within each ecosystem.

new revised edition kerri humphreys - · pdf filedefine producer, consumer and decomposer. ......

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