Unit 3 Life on Earth 1. Biodiversity and Human Impacts 2. Sampling Techniques 3. Energy Flow 4. Evolution

Biodiversity and Human Impacts Topic 1

Biodiversity Key Terms 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. Biodiversity match cards for these terms and definitions should be made by students during this first lesson.

Biodiversity 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 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! Research and poster activity for a particular biomes

Niches 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 Unit 3 revision question booklet should be used at this point to highlight the MCQ style questions.

Human Influences: Air Pollution 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: Deforestation 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: Intensive 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 This lesson could link into research of GM Crops and fertilisers for the assignment task.

Effect of Human Influences 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; The killing of lions recently in Africa could be used as a discussion and class debate?

Black Rhino

Endangered Californian Condor California Condor

Giant Panda Endangered

Endangered Snow Leopard

Endangered Blue Whale

Tiger Endangered

Mountain Gorilla Endangered Conservation fact file or ecological footprint calculating activity on the WWF web page.

Sampling Techniques Topic 2

Sampling Key Terms Abiotic Factors (Non-living factors) Biotic Factors (Living factors) Temperature Predation Light Intensity Disease Soil Moisture Grazing pH of Soil Food Availability Match card activity to understand Abiotic and Biotic factors.

Abiotic 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: Equipment 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 Sampling Take equipment into grounds and sample 3 different areas for comparison. Note your results in your jotters. ERRORS/ PREVENTIONS OFTEN EXAM QUESTIONS

Biotic Sampling: Equipment 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 suitable for sampling? Discuss. Experiment 2: Biotic Sampling Take equipment into grounds and set up your pitfall traps in various areas. We will return to them tomorrow for the results.

Biotic Sampling: Quadrats 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 Sampling Take equipment into grounds* and sample the field with your quadrat. Note any findings in your jotters. *Weather depending

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

Energy Flow in Ecosystems Topic 3

Energy Flow Key Terms Term 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 Chains 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 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. Experiment 4: Owl Pellet Dissection Tease apart the owl pellet to find out what it has eaten! Practice questions for food webs unit 3 revision book! Owl pellet dissection. FOOD WEB EXAM QUs WILL ALWAYS ASK HOW ONE SPECIES AFFECT ANOTHER (BALANCE)

Working 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 Examples 1. Parasites Present 2. Tree as Producer 3. Classic Example

Energy Flow: Nitrogen Cycle 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 Cycle Experiment 5: Root Nodules Prove that nitrifying bacteria can be found in root nodules by growing them on nitrogen free agar plates! Root Nodule Experiment

Convert ammonium into nitrites and then into nitrates 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 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!! Possible pause for research for assignment task on fertilisers?

Adaptation, Natural Selection and Evolution Topic 4

Adapt, Nat Selection & Evolution Key Terms 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.

Adaptations THINK! What are the ADAPTATIONS on the following examples? Are they STRUCTURAL/ BEHAVIOURAL? Example 1: Cactus Example 2: Polar Bear

Adaptations 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 temperatures 2. Exposure to radiation 3. Exposure to chemicals. THINK! Can you think of any mutations in humans which are advantageous/neutral or disadvantageous? Discuss.

Natural 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) There are 4 key stages to the evolution of a species.