Topic 5 reviewTopic 5 review

Populations – 5.3Populations – 5.3 5.3.1: Outline how population size can be affected 5.3.1: Outline how population size can be affected

by natality, immigration, mortality and emigrationby natality, immigration, mortality and emigration 5.3.2: Draw and label a graph showing the sigmoid 5.3.2: Draw and label a graph showing the sigmoid

(S-shaped) population growth curve(S-shaped) population growth curve 5.3.3: Explain reasons for the exponential growth 5.3.3: Explain reasons for the exponential growth

phase, the plateau phase and the transitional phase phase, the plateau phase and the transitional phase between these two phasesbetween these two phases

5.3.4: List three factors which set limits to 5.3.4: List three factors which set limits to population increasepopulation increase

What determines population growth?What determines population growth? Natality, Mortality, Immigration, EmmigrationNatality, Mortality, Immigration, Emmigration

What type of species grow exponentially, with What type of species grow exponentially, with density independent growth? density independent growth?

R-selected speciesR-selected species

What type of species shows density dependent What type of species shows density dependent growth that slows then plateaus over time?growth that slows then plateaus over time?

K-selected speciesK-selected species

So populations change bySo populations change by

Natality and Immigration increasing themNatality and Immigration increasing them Mortality and Emigration decreasing themMortality and Emigration decreasing them

SoSo Change = (N + I) – (D + E)Change = (N + I) – (D + E)

Figure 52.8 Population growth predicted by the exponential modelFigure 52.8 Population growth predicted by the exponential model

Figure 52.11 Population growth predicted by the logistic modelFigure 52.11 Population growth predicted by the logistic model

Phases of an S curvePhases of an S curve1.1. Exponential phase = population increases because natality Exponential phase = population increases because natality

rate is greater than mortality raterate is greater than mortality rate• Resources abundant, diseases & predation rareResources abundant, diseases & predation rare

2.2. Transitional phase = natality rate starts to slow +/or Transitional phase = natality rate starts to slow +/or mortality rate starts to increase. Natality still above mortality rate starts to increase. Natality still above mortality so population will still increase but less rapidlymortality so population will still increase but less rapidly

• Resources decreasing +/or Disease & Predation increaseResources decreasing +/or Disease & Predation increase

3.3. Plateau phase = Natality = Mortality so population size Plateau phase = Natality = Mortality so population size remains constantremains constant

• Something has limited the populationSomething has limited the population• It has reached carrying capacity (K)It has reached carrying capacity (K)

What is Carrying Capacity?What is Carrying Capacity? K = the maximum number of individuals that a K = the maximum number of individuals that a

particular environment can support at a particular particular environment can support at a particular time with no habitat degradationtime with no habitat degradation

What are the limiting factors that would cause What are the limiting factors that would cause carrying capacity?carrying capacity?

Limiting factors include Energy (food) available, Limiting factors include Energy (food) available, shelters, predators, diseases or parasites, soil shelters, predators, diseases or parasites, soil nutrients, water, suitable nesting & roosting sitesnutrients, water, suitable nesting & roosting sites

Ecosystems 5.1Ecosystems 5.1 5.1.1 – Define ecology, ecosystem, population, community, species 5.1.1 – Define ecology, ecosystem, population, community, species

& habitat& habitat 5.1.2 – Distinguish between autotroph (producer) and heterotroph 5.1.2 – Distinguish between autotroph (producer) and heterotroph

(consumer)(consumer) 5.1.3 – Distinguish between consumers, detritivores and 5.1.3 – Distinguish between consumers, detritivores and

saprotrophssaprotrophs 5.1.4 – Describe what is meant by a food chain giving three 5.1.4 – Describe what is meant by a food chain giving three

examples, each with at least 3 linkages (4 organisms)examples, each with at least 3 linkages (4 organisms) 5.1.5 – Describe what is meant by a food web5.1.5 – Describe what is meant by a food web 5.1.6 – Define trophic level5.1.6 – Define trophic level 5.1.7 – Deduce the trophic level of organisms in a food chain and 5.1.7 – Deduce the trophic level of organisms in a food chain and

food webfood web 5.1.8 – Construct a food web containing up to 10 organisms given 5.1.8 – Construct a food web containing up to 10 organisms given

appropriate informationappropriate information

5.1.9 – State that light is the initial energy source for almost all 5.1.9 – State that light is the initial energy source for almost all communitiescommunities

5.1.10 – Explain the energy flow in a food chain5.1.10 – Explain the energy flow in a food chain 5.1.11 – State that when energy transformations take place 5.1.11 – State that when energy transformations take place

including those in living organisms, the process is never 100% including those in living organisms, the process is never 100% efficient, commonly being 10 – 20%efficient, commonly being 10 – 20%

5.1.12 – Explain what is meant by a pyramid of energy and the 5.1.12 – Explain what is meant by a pyramid of energy and the reasons for its shapereasons for its shape

5.1.13 – Explain that energy can enter and leave an ecosystem, but 5.1.13 – Explain that energy can enter and leave an ecosystem, but that nutrients must be recycledthat nutrients must be recycled

5.1.14 – State that saprophytic bacteria and fungi (decomposers) 5.1.14 – State that saprophytic bacteria and fungi (decomposers) recycle nutrientsrecycle nutrients

DefinitionsDefinitions

EcologyEcology the study of relationships between living organisms and between organisms and the study of relationships between living organisms and between organisms and

their environmenttheir environment EcosystemEcosystem

a community and its abiotic environmenta community and its abiotic environment PopulationPopulation

a group of organisms of the same species who live in the same area at the same a group of organisms of the same species who live in the same area at the same timetime

Community Community a group of populations living and interacting with each other in an areaa group of populations living and interacting with each other in an area

SpeciesSpecies a group of organisms which can interbreed and produce fertile offspringa group of organisms which can interbreed and produce fertile offspring

HabitatHabitat the environment in which a species normally lives or the location of a living the environment in which a species normally lives or the location of a living organismorganism

Trophic levelTrophic level energy level in a food web / chainenergy level in a food web / chain

AutotrophAutotroph organism which makes its own food from inorganic materialsorganism which makes its own food from inorganic materials

HeterotrophHeterotroph organism that depends directly or indirectly on producers for energyorganism that depends directly or indirectly on producers for energy

What is a …What is a …

Consumer?Consumer? Eats another organism as an energy source – Eats another organism as an energy source –

heterotrophicheterotrophic Zebra, lionZebra, lion

Detritivore?Detritivore? get their energy from detritus, nonliving organic material get their energy from detritus, nonliving organic material

remains of dead organisms feces, fallen leaves, wood remains of dead organisms feces, fallen leaves, wood Dung beetles, earth wormsDung beetles, earth worms

Saprotroph?Saprotroph? feed on dead organic material by secreting digestive feed on dead organic material by secreting digestive

enzymes into it and absorbing the digested productsenzymes into it and absorbing the digested products Bread mold, mushrooms Bread mold, mushrooms

ProducerProducer Passion FlowerPassion Flower Carrot plantCarrot plant Sea lettuceSea lettuce

Primary Primary ConsumerConsumer

Heliconius Heliconius butterflybutterfly

Carrot flyCarrot fly Marine iguanaMarine iguana

Seconday Seconday ConsumerConsumer

Tegu lizzardTegu lizzard FlycatcherFlycatcher Galapagos snakeGalapagos snake

Tertiary Tertiary ConsumerConsumer

JaguarJaguar SparrowhawkSparrowhawk Galapagos HawkGalapagos Hawk

Quarternary Quarternary ConsumerConsumer

GoshawkGoshawk

Food chains are linear diagrams to show feeding Food chains are linear diagrams to show feeding relationships and energy flowrelationships and energy flow

An Antarctic marine An Antarctic marine food web – no show food web – no show

organisms at multiple organisms at multiple trophic levels to trophic levels to indicate the true indicate the true complexity of the complexity of the

feeding relationships feeding relationships and energy flowand energy flow

Can you deduce the Can you deduce the trophic level for each trophic level for each

organism you see?organism you see?

Now create a food web – remember the direction of your arrows!

The initial source of energy for most The initial source of energy for most communities is the…communities is the…

SunSun

Explain the energy flow in one of these food chains

What percent of the energy in zooplankton could be expected to be transferred to the small carnivorous fish?

If there are 20 Joules of energy in a grasshopper, how much of that is left for the hawk?

Energy pyramidsEnergy pyramids

So energy and matter move So energy and matter move differentlydifferently

Energy Energy flowsflows through the system – in from the through the system – in from the sun out by heatsun out by heat

Matter must be Matter must be recycledrecycled though because there though because there is no new matter coming in to replace used is no new matter coming in to replace used mattermatter

Syllabus statementsSyllabus statements 5.4.1: Define evolution5.4.1: Define evolution 5.4.2: Outline the evidence for evolution provided by the fossil 5.4.2: Outline the evidence for evolution provided by the fossil

record, selective breeding of domesticated animals, and record, selective breeding of domesticated animals, and homologous structureshomologous structures

5.4.3: State that populations tend to produce more offspring that 5.4.3: State that populations tend to produce more offspring that the environment can supportthe environment can support

5.4.4: Explain that the consequence of the potential 5.4.4: Explain that the consequence of the potential overproduction of offspring is a struggle for survivaloverproduction of offspring is a struggle for survival

5.4.5: State that the members of a species show variation5.4.5: State that the members of a species show variation 5.4.6: Explain how sexual reproduction promotes variation in a 5.4.6: Explain how sexual reproduction promotes variation in a

speciesspecies 5.4.7: Explain how natural selection leads to evolution5.4.7: Explain how natural selection leads to evolution 5.4.8: Explain two examples of evolution in response to 5.4.8: Explain two examples of evolution in response to

environmental change; one must be multiple antibiotic resistance environmental change; one must be multiple antibiotic resistance in bacteria in bacteria

Evolution BasicsEvolution Basics

Evolution = The change in the genetic Evolution = The change in the genetic composition of a population over timecomposition of a population over time

Changes in gene frequency over timeChanges in gene frequency over time

Evidence for evolutionEvidence for evolution

Evidence indicates that species evolve by Evidence indicates that species evolve by natural selection over longer time periodsnatural selection over longer time periods

Evolution is validated by evidence from Evolution is validated by evidence from homologyhomology similarities between species due to similarities between species due to

common ancestrycommon ancestry Selective breeding Selective breeding Breeding organisms for Breeding organisms for

specific traitsspecific traits Biogeography Biogeography distribution of living species distribution of living species Fossils Fossils Form and distribution validate the Form and distribution validate the

theorytheory

Principles of EvolutionPrinciples of Evolution

1.1. Populations tend to produce more offspring that the Populations tend to produce more offspring that the environment can supportenvironment can support

2.2. Members of a species show variationMembers of a species show variation3.3. The resources in the environment are limitedThe resources in the environment are limited4.4. The consequence of the potential overproduction of The consequence of the potential overproduction of

offspring is a struggle for survivaloffspring is a struggle for survival5.5. Some variations are favorable in this struggleSome variations are favorable in this struggle6.6. Those individuals with favorable variations will pass Those individuals with favorable variations will pass

on their genes to the next generation in higher numberson their genes to the next generation in higher numbers7.7. Gene frequency changes to represent the fittest Gene frequency changes to represent the fittest

organisms “SURVIVAL OF THE FITTEST”organisms “SURVIVAL OF THE FITTEST”

Consequences of Overproduction of Consequences of Overproduction of OffspringOffspring

1.1. Food might become scarceFood might become scarce

2.2. Territories might be limiting for both mating Territories might be limiting for both mating and reproducingand reproducing

3.3. Density might get so great that disease and Density might get so great that disease and parasites would become epidemicsparasites would become epidemics

4.4. Predator populations will also grow because of Predator populations will also grow because of the increase in population size of prey, and the increase in population size of prey, and begin to whittle down the herd.begin to whittle down the herd.

Role of SexRole of Sex

Living organisms vary as a result of sexual Living organisms vary as a result of sexual reproductionreproduction

Meiosis allows a large variety of genetically different Meiosis allows a large variety of genetically different gametes to be produced by each individual (2gametes to be produced by each individual (2nn))

This occurs through segregation of maternal and This occurs through segregation of maternal and paternal chromosomes and crossing over in prophase paternal chromosomes and crossing over in prophase I of meiosisI of meiosis

Fertilization allows alleles from 2 different Fertilization allows alleles from 2 different individuals to be brought together in one new individuals to be brought together in one new individualindividual

Evolution in response to environmental Evolution in response to environmental change: antibiotic resistencechange: antibiotic resistence

Evolution in response to environmental Evolution in response to environmental change: pesticide resistencechange: pesticide resistence

Taxonomy syllabus statementsTaxonomy syllabus statements 5.5.1 – Outline the binomial system of nomenclature5.5.1 – Outline the binomial system of nomenclature Define speciesDefine species 5.5.2 – List the seven levels in the hierarchy of taxa – kingdom, 5.5.2 – List the seven levels in the hierarchy of taxa – kingdom,

phylum, class, order, family, genus, species – using an example from phylum, class, order, family, genus, species – using an example from two different kingdoms for each leveltwo different kingdoms for each level

5.5.3 Distinguish between the following phyla of plants, using simple 5.5.3 Distinguish between the following phyla of plants, using simple external recognition features: bryophyta, filicinophyta, coniferophyta external recognition features: bryophyta, filicinophyta, coniferophyta and angiospermophyta.and angiospermophyta.

5.5.4 Distinguish between the following phyla of animals, using 5.5.4 Distinguish between the following phyla of animals, using simple external recognition features: porifera, cnidaria, simple external recognition features: porifera, cnidaria, platyhelminthes, annelida, mollusca and arthropoda.platyhelminthes, annelida, mollusca and arthropoda.

5.5.5 – Apply and/or design a key for a group of up to eight organisms5.5.5 – Apply and/or design a key for a group of up to eight organisms

Binomial Nomenclature SystemBinomial Nomenclature System

Created by C. LinneausCreated by C. Linneaus Each species has 2 part Latin nameEach species has 2 part Latin name Genus speciesGenus species (computer) (computer) Genus speciesGenus species (handwritten) (handwritten) E.g. E.g. Homo sapiens Homo sapiens = humans= humans

Felis sylvestrisFelis sylvestris = house cat = house cat

Ranunculus acris = Ranunculus acris = buttercutbuttercut

Remember: KPCOFGSRemember: KPCOFGS(memorize the following examples)(memorize the following examples)

LevelsLevels Domestic CatDomestic Cat Common Common ButtercupButtercup

HumanHuman

KingdomKingdom AnimaliaAnimalia PlantaePlantae AnimaliaAnimalia

PhylumPhylum ChordataChordata AnthophytaAnthophyta ChordataChordata

ClassClass MammaliaMammalia DicotyledonsDicotyledons MammaliaMammalia

OrderOrder CarnivoraCarnivora RanunculalesRanunculales PrimatesPrimates

FamilyFamily FelidaeFelidae RanunculacaeRanunculacae HominidaeHominidae

GenusGenus FelisFelis RanunculusRanunculus HomoHomo

SpeciesSpecies sylvestrissylvestris acrisacris sapienssapiens

Organisms that are in a particular level of the Organisms that are in a particular level of the taxonomic hierarchy together share all the taxonomic hierarchy together share all the levels above and may or may not share the levels above and may or may not share the levels belowlevels below

PlantsPlants

Bryophyta: mosses, liverworts, hornworts – short, Bryophyta: mosses, liverworts, hornworts – short, nonvascular, no roots, live in moist and harsh nonvascular, no roots, live in moist and harsh environments, environments,

Filicinophyta: ferns, clubmosses, wiskferns, Filicinophyta: ferns, clubmosses, wiskferns, horsetails - vascular, spores, need water for horsetails - vascular, spores, need water for reproduction, simple leaves, reproduction, simple leaves,

Coniferophyta: conifers, cycadsConiferophyta: conifers, cycads,, ginkgo, and the ginkgo, and the gnetophytes – small waxy leaves, naked seeds, larger, gnetophytes – small waxy leaves, naked seeds, larger,

Angiospermophyta: flowering plants – fruits, Angiospermophyta: flowering plants – fruits, flowers, most diverse, monocots and dicotsflowers, most diverse, monocots and dicots

AnimalsAnimals Porifera: sponges – sessile, lack tissues, filter feedersPorifera: sponges – sessile, lack tissues, filter feeders Cnidaria: anemones, corals, hydra, jellies – nematocysts, Cnidaria: anemones, corals, hydra, jellies – nematocysts,

radial symmetry, polyp or medusaradial symmetry, polyp or medusa Platyhelminthes: flatworms – bilateral symmetry, flat, only Platyhelminthes: flatworms – bilateral symmetry, flat, only

one GI tract openingone GI tract opening Annelida: segmented worms (oligocheates, polycheates, Annelida: segmented worms (oligocheates, polycheates,

hirudinea) – repeated segments on bilaterally symmetrical hirudinea) – repeated segments on bilaterally symmetrical bodybody

Mollusca: bivalves, cephlopods, gastropods, chitons – Mollusca: bivalves, cephlopods, gastropods, chitons – bilateral symmetry, 3 body partsbilateral symmetry, 3 body parts foot, visceral mass, foot, visceral mass, mantlemantle

Arthropoda: insects, crustaceans – exoskeletons and jointed Arthropoda: insects, crustaceans – exoskeletons and jointed appendagesappendages

Create & Apply A Dichotomous

Key

Syllabus StatementsSyllabus Statements 5.2.1: draw and label a diagram of the carbon cycle to show the 5.2.1: draw and label a diagram of the carbon cycle to show the

processes involvedprocesses involved 5.2.2: Analyse the changes in concentration of atmospheric carbon 5.2.2: Analyse the changes in concentration of atmospheric carbon

dioxide using historical recordsdioxide using historical records 5.2.3: Explain the relationship between rises in concentrations of 5.2.3: Explain the relationship between rises in concentrations of

atmospheric carbon dioxide, methane and oxides of nitrogen and the atmospheric carbon dioxide, methane and oxides of nitrogen and the enhanced greenhouse effectenhanced greenhouse effect

5.2.4: Outline the precautionary principle5.2.4: Outline the precautionary principle 5.2.5: Evaluate the precautionary principle as a justification for 5.2.5: Evaluate the precautionary principle as a justification for

strong action in response to the threats posed by the enhanced strong action in response to the threats posed by the enhanced greenhouse effectgreenhouse effect

5.2.6: Outline the consequences of a global temperature rise on arctic 5.2.6: Outline the consequences of a global temperature rise on arctic ecosystemsecosystems

Figure 54.17 The carbon cycleFigure 54.17 The carbon cycle

Greenhouse Effect & Global Greenhouse Effect & Global WarmingWarming

Incoming short wave radiation (visible and UV) is Incoming short wave radiation (visible and UV) is transmitted through the atmosphere transmitted through the atmosphere

Much of solar radiation that strikes the planet is reflected Much of solar radiation that strikes the planet is reflected back into spaceback into space

Although COAlthough CO22 and water vapor in the atmosphere are and water vapor in the atmosphere are transparent to visible light, they absorb much of the transparent to visible light, they absorb much of the reradiated long wave radiation (infrared radiation)reradiated long wave radiation (infrared radiation)

Some reflected back and retained to heat up the earthSome reflected back and retained to heat up the earth If not for the natural Greenhouse effect the earth’s surface If not for the natural Greenhouse effect the earth’s surface

temperature would be 18 temperature would be 18 ooC C most life would not exist most life would not exist

So…So…

Main atmopsheric gases involved are COMain atmopsheric gases involved are CO22,,

methane, water vapor, CFC’smethane, water vapor, CFC’s If we put more of those gases into the If we put more of those gases into the

atmosphere from our activities, we should atmosphere from our activities, we should expect a corresponding increase in temperatureexpect a corresponding increase in temperature

Do we put in more?Do we put in more?

Human activities increase the Human activities increase the Greenhouse EffectGreenhouse Effect

Gases: COGases: CO22,, methane, water vapor, CFC’s methane, water vapor, CFC’s

COCO22 Released from combustion of fossil fuels Released from combustion of fossil fuels (coal, oil natural gas)(coal, oil natural gas)

Burning of wood from deforestationBurning of wood from deforestation MethaneMethane release from the digestive tracts of release from the digestive tracts of

ruminants (cows)ruminants (cows) Swamps, rice paddies, landfillsSwamps, rice paddies, landfills CFC’sCFC’s used as refrigerants, propellants in used as refrigerants, propellants in

cans, gas blown plasticscans, gas blown plastics

Historical RecordsHistorical Records

We see trends of increased COWe see trends of increased CO22 emissions in emissions in

measures taken since 1950’smeasures taken since 1950’s Mona Loa and Cape Grim Tazmania, show Mona Loa and Cape Grim Tazmania, show

fluctuating increasefluctuating increase Peaks in our winter, dips in our summer – Peaks in our winter, dips in our summer –

depends on photosynthesis depends on photosynthesis Longer term trends in COLonger term trends in CO22 seen in ice core seen in ice core

datadata

Consequences for Arctic ecosystemsConsequences for Arctic ecosystems

Increased decomposition rates of organic material Increased decomposition rates of organic material trapped in the ice capstrapped in the ice caps

Expansion of temperate species into the polar habit Expansion of temperate species into the polar habit Loss of ice habitat – Polar bears threatenedLoss of ice habitat – Polar bears threatened Changes in prey distribution, effecting top predatorsChanges in prey distribution, effecting top predators Increased success of pests and pathogens.Increased success of pests and pathogens.

The Precautionary PrincipleThe Precautionary Principle

If the effects of human induced climate change If the effects of human induced climate change would be large or catastrophicwould be large or catastrophic

Those responsible for the changes must prove Those responsible for the changes must prove that they that they are not harmfulare not harmful before proceeding before proceeding

This is the reverse of the normal conditionThis is the reverse of the normal condition

The Precautionary PrincipleThe Precautionary Principle

In other words if Human disturbances are In other words if Human disturbances are disrupting ecosystem processesdisrupting ecosystem processes

Our ignorance of long term effects means we Our ignorance of long term effects means we should be cautiousshould be cautious

Thus, “When there is considerable evidence that Thus, “When there is considerable evidence that and activity threatens human and ecosystem and activity threatens human and ecosystem health, we should take precautions to minimize health, we should take precautions to minimize harm, even if the effects are not fully known.”harm, even if the effects are not fully known.”

Better safe than sorry…Better safe than sorry…

Does the economic harm of measures taken Does the economic harm of measures taken now to limit global warming, offset the now to limit global warming, offset the potentially greater harm that inaction would potentially greater harm that inaction would present to future generations?present to future generations?

The ethics of itThe ethics of it Is it right to jeopardize the health & welfare of Is it right to jeopardize the health & welfare of

future human populations?future human populations? Is it right to do damage to habitats and drive Is it right to do damage to habitats and drive

species to extinction?species to extinction?