Chapter 8
The study of a habitat
Ecology Ecology is the study of how plants and animals interact with o each other and with o their environment. Ecosystems are similar groups of plants, animals and environments. Name the ecosystems shown in the following images: A habitat is the place where a plant or an animal lives.
The study of a habitat The study of a habitat (such as a grassland) involves 5 steps: 1. Draw a simple map of the habitat (or photograph it if possible). 2. Measure and record the non-living environmental features in the habitat. 3. Identify and name all the organisms in the habitat. 4. Collect samples of those organisms that cannot be named. 5. Estimate the number of each plant in the habitat.
Step 1 Map the habitat o Draw a simple map (or take a photograph) to show the main features of the area being studied. o E.g. walls, fences, ponds, large trees, hedges or paths
Step 2 Measure the non-living (environmental) factors o Non-living factors are called abiotic factors. o The table below shows some of the abiotic factors that can be measured (along with the equipment used to measure them).
Step 3 Name the organisms in the habitat by: o comparing them to a photograph or drawing in a book o using a key. o Keys are used to help identify organisms
Homework Book p69 Q8.1, 8.2 8.3
Step 4 Collect plants and animals in a habitat
Homework Book p70 Q 8.5, 8.6
Step 5 Estimate the number of each plant in the habitat A Quadrat is a square used to estimate the number of plants in a habitat. A line transect is a rope marked at regular intervals and laid out across a habitat to estimate the number of plants present.
Activity 8.3: How can we estimate the number of plants in a habitat? 1. Throw a pencil/ball over your shoulder in the habitat. 2. Place a quadrat on the ground where the ball lands. 3. Record the names of all the plants in the quadrat. 4. Repeat this ten times in different parts of the habitat. 5. Record your results as shown in the table below. 6. Draw a bar chart of the results
Home work Book pg 72 Q8.7, 8.8
Adaptation An adaptation is a structure or habit that helps an organism to survive. Examples of adaptations are: o Plants such as primroses produce flowers early in spring (before other plants have produced their leaves). o Grasses grow from the base (unlike most plants which grow from their tips). o Caterpillars have similar colours to the plants they feed on. (camouflage) o Butterflies have long tube-like mouth parts so they can drink nectar. A community consists of all the organisms living in a particular area
Homework Book p72 Q8.9, 8.10
Competition Competition takes place when two or more living things require something that is in scarce supply. Animals compete for: o space o food o water o partners. Plants compete for: o light o space o water o minerals.
Types of Competition 1. Competition often occurs between members of the same type. o Grasses compete with each other for light. o Foxes compete with each other for food. 2. Competition sometimes occurs between members of different types. o Grasses and dandelions compete for light. o Robins and blackbirds compete for food.
Interdependence Interdependence means that organisms depend on each other for their survival. o Animals depend on plants for food, rabbit depends on grass o Plants depend on animals for pollination, flowers depend on bees o Plants depend on each other for shelter. o Animals depend on other animals for food, foxes depend on rabbits
Food interdependence Animals depend on plants for their food (food interdependence). Organisms get food in three main ways. o Producers (green plants) make their own food (by photosynthesis). o Consumers (animals) get their food by eating plants (or by eating other animals who have eaten plants). o Decomposers (woodlice, earthworms, bacteria and fungi) feed on dead plants and animals. Ø Decomposers return chemicals back into the soil to be used by other organisms.
Homework p75, Q8.12
Consumers There are three types of consumers: 1. Herbivores are animals that eat plants only (e.g. rabbits, sheep). 2. Carnivores are animals that eat other animals (e.g. foxes, hawks). 3. Omnivores are animals that eat plants and other animals (e.g. badgers, thrushes).
Food chain A food chain is a list of organisms in which each one is eaten by the next one in the chain. A simple food chain is:
Decomposers Food chains involve decomposers.
Food web A food web is a number of interlinked food chains.
Homework p77, Q8.13
Energy Energy is the ability to do work In an ecosystem energy flows along a food chain from the producer to the different consumers. The main energy source is the sun (solar energy). Producers convert solar energy into food (in a process called photosynthesis). In a food chain, energy: o flows from each organism to the next one in the chain o is lost (as heat, excreted materials, uneaten materials by the organisms in the food chain). Only about 10% of the energy is passed from organism to organism in a food chain. The huge loss of energy means that food chains cannot be too long.
Homework p77 Q8.14
Matter In an ecosystem matter flows along a food chain from the producer to the different consumers. For example: o calcium is absorbed from the soil by grass roots. o Calcium passes from grass to cows when the cows eat grass. o Calcium passes to humans when we drink milk. Unlike energy, matter is not lost from an ecosystem. Matter is recycled. For example: o calcium passes from the soil to grass and then to the cow and then to humans. o However calcium is released back into the soil when: Ø plants decay Ø animals decay Ø animal wastes (urine and faeces) decay. Matter is said to cycle in an ecosystem.
Photo credits Michael Philips QBS Shutterstock