1. Biodiversity and Human Impacts

2. Sampling Techniques

3. Energy Flow

4. Evolution

Topic 1

Biodiversity Key TermsBiodiversity Key TermsTerm Definition

Biodiversity Variety of living organisms on Earth.

Biomes Regions of our planet as distinguished by their similar climate, flora and fauna e.g. tundra

Habitat Place an organism lives.

Ecosystem Habitat + Community

Community All the living organisms in an area.

Population A group of living organisms of the one type e.g. dogs

Species A group of living organisms which are able to interbreed to produce fertile offspring.

Niche Description of organisms lifestyle/ Role it plays.

BiodiversityBiodiversity

• Biodiversity is the term used to describe the variety of living things in an ecosystem.

•Various factors can affect the biodiversity within an ecosystem, some of which include;- Abiotic factors - Biotic factors- Human influences-Natural hazards

•It is important that Biologists keep a close eye on Biodiversity as ecosystems are delicately balanced.

Understanding BiomesUnderstanding Biomes

• Earth is divided into distinct climate zones called BIOMES.

•Each biomes contains it’s own animals (fauna), plants (flora) and climate (temperature and rainfall).

•Plants and animals within these biomes are specially adapted to survive in their surroundings.

•THINK! What animals/plants do you find in the tropical rainforest? Are these the same in the desert or the polar regions on earth? Discuss why!

NichesNiches

•A NICHE is the term used to describe the lifestyle/ role that an organism plays within its ecosystem.

•Factors to consider when describing a niche include:- How that particular organism affects/is affected by other things around it- How it survives/competes

• NICHES OFTEN COME UP AS EXAM MCQs

Human Influences: Air Human Influences: Air PollutionPollution

•Car exhaust fumes contain sulphur dioxide and nitrogen oxides (NOx gases) which combine with rain water to form acid rain.

•THINK! Why is acid rain problematic? Discuss.

Human Influences: Human Influences: DeforestationDeforestation•Deforestation is the clearing of vast areas of natural forest without replanting replacement forests.

•There are many severe consequences of deforestation:- habitat destruction for many organisms- low-lying downstream areas become flooded- reduced soil fertility of hillsides- higher levels of CO2 contribute to greenhouse effect (climate change)

Human Influences: Human Influences: Intensive AgricultureIntensive Agriculture•Farmers create conditions that favour one or two chosen kind of crop plants and thus reduce the natural biodiversity.

•Farmers will do this by using:•Herbicides to kill other plants•Pesticides to kill pests that reduce crop value•Fertilisers that favour the chosen crop•Planting GM Crops•Remove hedges for easier harvesting

Effect of Human Effect of Human InfluencesInfluences

•Human activities, e.g. pollution, habitat destruction and over hunting, are to blame for the current wave of extinctions.

•Currently, extinction is happening x400 than the natural rate

•There are several different species threatened with extinction today including;

Black Rhino

Endangered

Californian Condor

California Condor

EndangeredGiant Panda

Endangered

Snow Leopard

EndangeredBlue Whale

EndangeredTiger

EndangeredMountain Gorilla

Topic 2

Sampling Key TermsSampling Key TermsAbiotic Factors (Non-living factors)

Biotic Factors (Living factors)

Temperature Predation

Light Intensity Disease

Soil Moisture Grazing

pH of Soil Food Availability

Abiotic SamplingAbiotic Sampling•Abiotic factors are the NON-LIVING components of any ecosystem.

•Experimental sampling of abiotic factors requires good technique to avoid errors whilst using the equipment.

• Just as with any experiment it is fundamental that the readings are Repeated for Reliable Results.

Abiotic Sampling: Abiotic Sampling: Equipment and ErrorsEquipment and Errors

Abiotic Factor

Equipment Required

Avoiding Error

Temperature

Thermometer Leave thermometer to settle for a few minutes before taking a reading.

Light Intensity

Light Intensity Meter

Do not cast a shadow over the solar panel. Stand to the side when taking readings.

pH of Soil Soil pH Meter Wipe the probe clean between samples to prevent any cross contamination.

Soil Moisture

Soil Moisture Meter

Wipe the probe clean between samples to prevent cross contamination.

Experiment 1: Abiotic SamplingTake equipment into grounds and sample 3 different areas for comparison.Note your results in your jotters.

ERRORS/ PREVENTIONS OFTEN EXAM QUESTIONS

Biotic Sampling: Biotic Sampling: Equipment and ErrorsEquipment and Errors•Biotic factors are the LIVING components of any ecosystem. The method used to sample the organisms depends on the type of species being studied.

•Experimental sampling of biotic factors requires good technique and set up of equipment to avoid errors.

Biotic Sampling: Pitfall Traps•Pitfall traps are a simple method which is used to sample small invertebrates such as insects found in leaf litter/on the floor of woodland etc.

•It is essential that the cup is buried level with the soil surface and is well camouflaged with leafs.

•THINK! Why is it important to camouflage the top of the cup? What other problems might arise? Are there any types of insects which this method is NOT suitablefor sampling? Discuss.

Experiment 2: Biotic SamplingTake equipment into grounds and set up your pitfall traps in various areas.

We will return to them tomorrow for the results.

Biotic Sampling: Biotic Sampling: QuadratsQuadrats•For plants and animals which don't move much (i.e. limpets) quadrats are normally used to sample their numbers in an area.

•Quadrats must be repeatedly thrown RANDOMLY in the area for reliable results.

•Sources of error include the difficulty in identifying the species present and deciding whether or not to include a plant which is partially present in the grid.

Experiment 3: Biotic SamplingTake equipment into grounds* and sample the field with your quadrat. Note any findings in your jotters.*Weather depending

Biotic Sampling: Other Biotic Sampling: Other MethodsMethods

•Other ways of sampling living organisms that you should be aware of include;- Tree Beating- Tulgren Funnel- Transect- Water Net

Topic 3

Energy Flow Key TermsEnergy Flow Key TermsTerm Definition

Herbivore Animal which only eats plants

Omnivore Animal which eats both plants and other animals

Carnivore Animal which only eats other animals

Intraspecific Competition

Competition between the SAME species

Interspecific Competition

Competition between DIFFERENT species

Pyramid of Numbers Pictorial diagram showing the relative numbers of each organism in a food chain.

Pyramid of Biomass Pictorial diagram showing the relative DRY MASS of each organism in a food chain.

Pyramid of Energy Pictorial diagram showing the relative energy at each level in the food chain.

Energy Flow: Food Energy Flow: Food ChainsChains

•Food chains show the DIRECTION of energy flow from producer (green plants) to consumer.

•Only 10% of energy is passed on at each level in a food chain.

•The other 90% is used in cellular processes, movement, homeostasis (temperature regulation) and excreted as waste.

Energy Flow: Food WebsEnergy Flow: Food Webs

• Food webs are different from food chains as they show intraspecific competition over food sources thus providing a more complete picture of the energy flow.

FOOD WEB EXAM QUs WILL ALWAYS ASK HOW ONE SPECIES AFFECT ANOTHER (BALANCE)

Experiment 4: Owl Pellet DissectionTease apart the owl pellet to find out what it has eaten!

Working with PyramidsWorking with Pyramids

•Pyramids are used by Biologists to highlight in a pictorial fashion what information they can gather about food chains.

•Pyramids of numbers represent how many of each organism there are in one food chain whilst Pyramids of Biomass show the DRY mass of each organism in a food chain.

•The shape of these pyramids often form a classic triangle however there are exceptions for number pyramids e.g. when parasites are present or when a large tree is the initial producer.

Pyramid Shape ExamplesPyramid Shape Examples1. Parasites Present 2. Tree as Producer3. Classic Example

Energy Flow: Nitrogen Energy Flow: Nitrogen CycleCycle•It is essential that Nitrogen is recycled between food webs and the ecosystem (Circle of Life).

•Nitrogen is needed to make PROTEINS but cannot be absorbed in gaseous form by plants or animals.

•Plants must absorb Nitrogen in the form of NITRATES from the soil as shown in the Nitrogen cycle on the next slide.

The Nitrogen CycleThe Nitrogen Cycle

Experiment 5: Root NodulesProve that nitrifying bacteria can be found in root nodules by growing them on nitrogen free agar plates!

Type of Bacteria Role in Nitrogen Cycle

Decomposers Decompose (breakdown) the nitrogen found in dead bodies and waste into ammonium

Nitrifying Convert ammonium into nitrites and then into nitrates

Denitrifying Breakdown nitrates releasing nitrogen gas into the air

Nitrogen Fixing ‘Fix’ nitrogen gas from the air into nitrates or protein

Over Use of FertilisersOver Use of Fertilisers•Farmers often use fertilisers to increase the nutrients in their soil; particularly Nitrogen.

•Many problems can arise due to fertiliser over-use; in particular EUTROPHICATION due to nutrients feeding bacteria and causing ALGAL BLOOMS which lead to DECREASED BIODIVERSITY.

4 MARK EXAM QU. MAKE SURE YOU KNOW THE

NITROGEN CYCLE AND PROBLEMS!!

Topic 4

Adapt, Nat Selection & Adapt, Nat Selection & Evolution Evolution Key TermsKey Terms

Term Definition

Mutation A random change to genetic material (DNA)

Adaptation An inherited characteristic that makes an organism suited to its environment

Natural Selection Favourable alleles (genes) are passed on to the next generation.

Evolution Changes which have occurred over long periods of time to develop new species from one common ancestor.

AdaptationsAdaptations

Example 1: CactusExample 2: Polar Bear

THINK! What are the ADAPTATIONS on the following examples? Are they STRUCTURAL/ BEHAVIOURAL?

AdaptationsAdaptations•Adaptations can arise from a mutation which covets survival.

•Mutations can be advantageous, neutral or disadvantageous.

•The rate at which mutations appear can be affected by :1. Exposure to high temperatures2. Exposure to radiation3. Exposure to chemicals.

•THINK! Can you think of any mutations in humans which are advantageous/neutral or disadvantageous? Discuss.

Natural SelectionNatural Selection•Natural selection is when alleles (genes) which are favorable to the survival of the species are passed on to the next generation.

•The classic example is the peppered moth in Britain:

- White form original (1800s)- Industrial revolution- Soot covered trees- Mutation for colour arose- Black form survived predation- Decrease in pollution means both forms exist today

Evolution (Speciation)Evolution (Speciation)•There are 4 key stages to the evolution of a species.