Unit 3 test Flashcards
Define: biodiversity
The total variation of living organisms in a singular area
Define: producers
Plants which produce their own energy/food
Define: consumers
Organisms which obtain food/energy by feeding off producers or consumers
Define: herbivores
Organisms which only eat plant material
Define: carnivores
Organisms which only eat other animals
Define: omnivores
Organisms which eat both plant and animals
Define: predator
Organisms which hunt, kill and feed on another organism
Define: prey
Organisms which are hunted, killed and eaten by another organism
Define: habitat
The area in which an organism lives
Define: population
All the members of one species in a habitat
Define: community
All the organisms in a habitat
Species
Organisms which can interbreed with one another to produce fertile offspring
Food chain/web
Diagrams which show the feeding pattern/relationship between organisms
What is a niche
An organisms role in an ecosystem
Define: ecosystem
The physical habitat and all the living organisms that interact within it.
Define: competition
Conflict between organisms who require the same, finite resources
What are the two main types of competition
+ interspecific
+ intraspecific
What is interspecific competition
Conflict between organisms of different species over the same resources
What is intraspecific competition
Competition between members of the same species over the same resources
What is abiotic factor
A non-living factor such as temperature which affects the life of an organism
What is a biotic factor
A living factor that involves the interaction between living things such as predation
How do you measure:
- temperature
- pH
- light intensity
- soil moisture
- thermometer
- pH meter/ universal indicator
- light meter
- moisture meter
What are two sampling techniques for measuring abiotic factors
Pitfall traps and quadrats
What is a pitfall trap
A small hole in the ground lined with a container that has alcohol at the bottom. It aims to capture and count, small ground dwelling creatures by sedating them with the alcohol. A rock is placed as an overhead roof with a small gap underneath to allow the crawl in
What is a quadrat
A square, metal grid that is randomly throwing in an area and used to count the number of specific organisms in the square. This is multiplied by the total number of squares to give a representative average for the area.
What is an indicator species
An organism which indicates the environmental quality of an area through its presence or absence.
What is photosynthesis
The process used by green plants to produce their own food and therefore energy. Due to this process, these plants can be classified as producers.
What is the general equation of photosynthesis
Carbon dioxide + water -> oxygen + glucose
What is the chlorophyll
A pigment found in a plant cell’s chloroplasts that traps energy from the sun and converts it into chemical energy to be used during the photosynthesis process.
What is a carbohydrate
A compound that contains carbon, hydrogen and oxygen
What is the first stage of photosynthesis called
Light reactions
What occurs during stage 1
- Light energy from the sun is trapped in the chlorophyll and converted into chemical energy, in the form of ATP (from ADP + PI)
- This energy is used to split water into hydrogen and oxygen
- The ATP and oxygen are carried onto the next stage but the oxygen is expelled as a waste product.
What is the second stage of photosynthesis called
Carbon fixation
What occurs during stage 2
The hydrogen and ATP from stage 1 combine with the carbon dioxide in the air to produce glucose.
What are some of the uses of the glucose produced from photosynthesis
- stored as starch
- used in respiration
- used to produce cell structures such as cellulose
What are some limiting factors of photosynthesis
- raw material availability (water and carbon dioxide)
- light intensity
- quantity of heat energy
What is photosynthesis known as
An enzyme controlled reaction
How can you measure the rate of photosynthesis
+ rate of carbon dioxide intake
+ rate of oxygen production
+ rate of carbohydrate production
What do the arrows represent in a food chain/web
The direction of energy transfer
When is a food chain used
When there is a singular line of predation
When is a food web used
When there are multiple interconnected food chains
What happens to the energy as a food web progresses
It decreases as the individual organisms use it for their own bodily actions
How do organism use their energy
- growth of organism
- undigested materials
- heat
- movement
How much of the original energy of the organism is passed on from predator to prey
10%
What is a decomposer
An organism which decomposes undigested materials and waste products
What does the length of a bar represent in a pyramid of numbers
It is proportional to the number of organisms at each level
What is a fertiliser
A substance which increase the nitrate levels in the soil that plants grow in. This increases the crop growth rate and yield as these nitrates are essential in the plants formation of proteins . They also increase the nutrient levels required for plant growth
What is a disadvantage of fertilisers
Leaching
What is leaching
When a fertiliser runs into a water source and increase the nutrient levels int he water. This increases the growth of algae which blocks off the sunlight, preventing the marine plants to photosynthesise. This means no oxygen is produced and the rest of the marine life will suffocate and die.
What is a pesticide
Substances which are sprayed on plants to decrease competition by killing off harmful organisms.
What are… used to kill:
- pesticides
- herbicides
- fungicides
- insecticides
- animals
- weeds
- fungus
- insects
What is a disadvantage of pesticides
Bioaccumulation
What is bioaccumulation
The collection of pesticides within organism as they consume each other. Due to the fact that these pesticides do not decompose, they simply increase in concentration until they reach toxic levels at the higher ends of food chains. This causes the death of these higher level organisms.
What is an example of bioaccumulation
DDT. A toxic pesticide that hugely decreased the number of blue heron. It is now illegal
What is a GM crop
A genetically modified crop which can replace fertilisers and pesticides by changing their genetic material to be resistant to harmful organisms or allow them to grow in all weathers.
What is a biological control
A species or organism that is introduced to a habitat to reduce the number of another species in that habitat. It is a natural predator.
What is an example of a biological control
Introduction of ladybirds to a habitat to decrease and control the number of greenfly populations.
What is a mutation
A random change to an organisms genetic material, for in new alleles in the genotype.
What are some factors which can cause mutation
- radiation
- chemical exposure
Mutations can either be:
Advantageous, disadvantageous or neutral
What is an advantageous mutation
A mutation which gives the affected organisms an advantage over the rest of the population, increasing its chance of survival and reproduction.
What is a disadvantageous mutation + EXAMPLE
A mutation which gives the organism a disadvantage, making it more likely to die.
An example is the sickle cell mutation which forms an abnormal type of haemoglobin that is unable to carry much oxygen. This leads to the death of the organism as they cannot transport oxygenised blood to the body.
What is a neutral mutation
One which has no effect on the organism
What is the name given to factors which make some individuals better at surviving
Environment selection pressures
What is a species
Organisms which can interbreed with one another to produce fertile offspring
What is the process that is the forms new species
Speciation
What is the process of speciation
- An isolation barrier separates the population
- The two sub-populations adapt and mutate to the new, different surroundings.
- Over time they develop and reproduce so much that when returned to one another, they cannot produce fertile offspring - meaning two new species have been formed
What is an isolation barrier
A natural factor that separates a population
What are the three types of isolation barrier
+ geographical (mountains, rivers…)
+ ecological (temperature, humidity…)
+ behavioural (mating patterns, opposing niches)
