Ecology Flashcards
Ecology
Is the study of how living things interact with each other and their environment
An ecosystem
Is a group of living organisms and their interactions with their environment
Biosphere
Any part of earth where life can exist
Habitat
A place where a plant or animal lives
Population
All the members of the same species living in an area
Community
All the different populations that live in an area
Flora
Plants
Fauna
Animals
Niche
Functional role of an organism in an ecosystem
Abiotic
~ Non-living factors
~ e.g. altitude, aspect, light intensity and air speed
Biotic
~ Living factors
~ e.g. plants for food and shelter, predators, prey, parasites and pathogens, competitors, pollinators, and decomposers
Climatic
~ Weather conditions
~ e.g. temperature, rainfall, humidity, wind, light intensity and day length
Edaphic
~ Soil factors
~ e.g. soil type, soil pH and soil texture
Food chain
A sequence of organisms showing the transfer of energy from one to the next
Grazing food chain
~ One where the initial plant is living
~ Grass -> Rabbit -> Fox
Detritus food chain
~ Begins with dead organic matter and animal waste
~ Dead leaves -> Earthworms -> Thrush -> Hawk
Food web
Consists of a number of interlinked food chains and shows the feeding relationships between organisms in the ecosystem
Producers
Are organisms that can make their own food (autotrophs)
Consumers
~ Are organisms that cannot make their own food (heterotrophs)
~ Primary consumers feed on producers (herbivores), secondary consumers feed on primary consumers (carnivores) and tertiary consumers feed on secondary consumers
Herbivore
Only eats plants
Trophic levels
Is the position of an organism in a food chain
Carnivore
Only eats meat
Omnivore
Eats plants and animals
Pyramid of numbers
Represents the number of organisms at each trophic level in a food chain (Note inverted pyramid of numbers)
Nutrient recycling
~ The reuse of nutrients by organisms (if asked for definition only)
~ The way in which elements are exchanged between the living and non-living components of the ecosystem
Nitrogen fixation
Conversion of nitrogen gas into nitrates
Nitrification
Conversion of ammonia to nitrite and nitrite to nitrate
Dentrification
Conversion of nitrates into nitrogen gas
Pollution
Is any harmful addition to the environment
Pollutants
Are substances that cause pollution
Eutrophication
The over-enrichment of lakes with nutrients resulting from excess artificial fertilisers that have been washed into rivers and lakes. Algae bloom occurs and uses up the nutrients. The algae dies and is broken down by bacteria which uses up oxygen in the water, this leads to the death of aquatic organisms i.e. fish
Conservation
Is the management of the environment
Composting
Is an aerobic process during which micro-organisms decompose organic matter into a stable substance called compost which recycles all the nutrients required for plant growth
Competition
Struggle between organisms for resources that are in short supply
Contest competition
An active confrontation between two organisms for a resource where only one wins
Scramble competition
Each organism gets an equal share of the resource and there is no direct competition
Parasitism
A relationship in which one organism (the parasite) benefits from another (the host) and causes it harm
Parasite
A living organism that live on or in another organism causing it harm
Ectoparasite
Live on the host organism causing it harm e.g. fleas on a dog
Endoparasite
Live in the host causing it harm e.g. liver fluke in sheep
Predation
The capturing, killing and eating of other organisms for food
Predator
An animal that captures, kills and eats other animals for food
Prey
Are animals that are captured, killed and eaten by predators
Biological pest control
Introduction of predators to control a pest e.g. ladybird and the aphid
Symbiosis
Two organisms of different species that live in close association where at least one benefits e.g. bacteria living in the colon produce vitamin B and K
Sample ecosystems
Grassland, woodland, hedgerow, seashore and freshwater
Carbon cycle
~ Plants : Remove carbon for photosynthesis and return it through respiration
~ Animals : Get carbon by eating plants and release it through respiration
~ Micro-organisms : Return carbon to the environment when they decompose dead plants and animals
Importance of the carbon cycle
To balance carbon dioxide levels and used in photosynthesis in plants
Bacteria
Decay nitrogen waste to ammonia
Importance of the nitrogen cycle
To convert nitrogen to a useable form (nitrates) for living organisms
Types of pollutants
~ Industrial/Air pollution
~ Agricultural pollution : Pollutant -> Slurry and fertilisers
Caused by -> Washed or leached from the land
Result -> Formation of algae blooms and eutrophication
Benefits of conservation
Maintains biodiversity, a balance of nature and prevents extinction
Example of conservation in fishing
Net mesh size
Waste management
Reduce, re-use, recycle
Waste management in agriculture
Slurry
~ Problem : Pollutes rivers - eutrophication
~ Solution : Stored in slurry tanks and spread during misty weather
Limitations of the pyramid of numbers
~ Cannot be drawn to scale
~ Do not take into account the physical size of the organisms e.g. oak tree
Factors that control population
~ Competition
~ Parasitism
~ Predation
~ Symbiosis
Intra-specific competition
Between members of the same species
Inter-specific competition
Between members of different species
How do organisms survive competition?
~ Animals : Camouflage e.g. frogs or moving away from over-populated areas
~ Plants : Weeds survive because they produce large numbers of seeds and thrive in poorer soil conditions
How do parasites differ from predators?
Smaller and often attack within
Adaptions of predators
~ Excellent eyesight to locate prey e.g. eagles
~ Fly very quietly as to not alert prey e.g. owls
Adaptions of prey
~ Camouflage so they blend into the background to avoid being spotted
~ Have large ears to hear predators approaching e.g. rabbits
Factors affecting human population numbers
~ Famine
~ Disease
~ War
~ Contraception
