Higher Unit 3 Flashcards
What is food security?
The ability for the human population to access and use food stores
What is food sustainability?
The degree to which food security can be guaranteed
What are the 4 factors that determine food security?
+ availability
+ accessibility
+ usage
+ sustainability
What is each rank of a food chain known as
A trophic level
State the order of a food chain
Producers —> primary consumer —> secondary consumer —> tertiary consumer
How much energy is lost between tropics levels
90%
How is energy lost between trophies levels
+ heat from respiration
+ heat from undigested material
+ waste products
What is intensive farming
The act of maximising the efficiency of a small plot of land
What are the three aspects of intensive farming
+ pesticides
+ fertilisers
+ cultivars
What are pesticides
Chemical substances that reduce plant competition by killing pests and disease - promoting growth
What are fertilisers
Chemical substances that provide plants with increased nutrients - promoting growth
What are cultivars
Plant crops that have been bred to produce high yields with increased growth rates
What are the three possible fates of light, when coming into contact with a leaf
+ absorbed
+ transmitted
+ reflected
What are the three main photosynthetic pigments
+ chlorophyll a
+ chlorophyll b
+ the carotenoids
Describe the role of chlorophyll a
It absorbs blue and red colours of the visible spectrum, using their energy for photosynthesis
Describe the role of chlorophyll b
Same as chlorophyll a, but on a smaller scale
Describe the role of the carotenoids
Absorbe a wider range of light wave,entity’s and transfers the resultant energy to the chlorophylls
Why does chlorophyll have a green colour
As this is the one light wavelength that the pigments reflect instead of absorb
What is an action spectrum
A graph that shows the rate of photosynthesis at each wavelength of light, on the visible spectrum
What are the two stages of photosynthesis
+ photolysis
+ the Calvin cycle
Describe photolysis:
1: light energy is absorbed by the photosynthetic pigments
2: this energy is used to split water into hydrogen and oxygen
3: the hydrogen is accepted by NADP, creating NADPH
4: the oxygen is released
5: ATP is created from ADP + Pi
Describe the Calvin cycle
1: CO2 combines with RuBP to form 3PG, with the help of the RuBisCo enzyme
2: 3PG creates G3P
3: G3P synthesises Glucose, before regenerating RuBP
4: ATP and ADP+ Pi repeatedly form each other
5: NADP and NADPH repeatedly form each other
What are the 4 possible fates of glucose
+ produce energy in respiration
+ converted to starch for energy storage
+ converted to cellulose in cell walls
+ passed to other biosynthetic pathways
What is a plant field trial
An experimental investigation to test the effects of treatments, that occurs outside the laboratory (in the natural world)
What are the three requirements of a successful field trial
+ careful selection of treatments - increases validity
+ replication - increases reliability
+ randomisation - eliminates bias
What is selective breeding
When two parents with favourable alleles are bred together to produce advantageous offspring
What is outbreeding
When two unrelated members of a species mate
What is inbreeding
When two closely-related individuals mate
What is the result of inbreeding
The alleles of their offspring are more likely to be homozygous
What is inbreeding depression and what are its effects
When recessive alleles become homozygous and popular
Results in a loss of vigour, infertility or poor health
What is cross breeding
When organisms with different, but desirable, genotypes are mated
What is the produce of cross breeding
An F1 hybrid
What does an F1 hybrid display
Favourable alleles and hybrid vigour
Why must cross breeding parents be maintained
To allow F1 hybride to be repeatedly created, instead of the F2 hybrids - who have a wide range of genotypes that may be troublesome
How can desirable individuals be identified or created
Genomic sequencing and recombinant DNA technology
What are the three threats to crop growth
+ weeds
+ pests
+ pathogens
What are weeds
Plants that grow where they te not wanted and compete for resources
What is an annual weed
A weed that grows for one year, before dying and releasing a large amount of seeds
Give an example of an annual weed
Chickweed
Why is a perennial weed
A weed that suri des all year round, through their underground root storage, and can reproduce asexually.
Give an example of a perennial weed
Clover
What are pests and give an example
Small organisms that fed on crops, limiting their growth
An example of a crop pest is a slug
What is a pathogen
A vector that carries a plant disease, transmitting it to the crops in order to reduce their growth or kill them
What are the four control methods of weeds, pests and pathogens
+ cultural methods
+ pesticides
+ herbicides
+ biological controls
What are cultural methods
Traditional methods of crop growth promotion, that don’t require chemical substances. E.g. field ploughing
What are pesticides
Chemicals that kill pests or other unwanted organisms
What is a selective pesticide
One that only kills certain pests, meaning the ecosystem can function normally
What is a systemic pesticide
One that is taken up by a plant’s roots and transported to its tissues, killing pests that target certain areas of the plants
What is a herbicide
A chemical that kills weeds or other unwanted plants
What is a systemic herbicide
One that is applied to the soil, forcing the weeds to take it up and, subsequently, die
What is a biological control
A natural predator, pathogen or parasite that kills the unwanted organisms, preventing them from harming the plants
What is the term used to describe the use of biological controls, cultural controls and chemical controls
Integrated pest management (IPM)
What is the process by which pesticides and herbicides build up in an animal’s tissue
Bioaccumulation
What is the process by which the chemical concentration in an animal increases, as a food chain progresses
Biomagnification
What are the five freedoms of animal welfare
Freedom from…
\+ hunger and thirst \+ discomfort \+ pain, injury and disease \+ to express normal behaviour \+ fear and distress
What is animal welfare
The consideration of an animal’s mental and physical wellbeing
What are indicators of high animal welfare
Curiosity, alertness, play and interaction
What are indicators of poor animal welfare
failure in sexual or parental behaviour, hysteria, apathy or stereotypy
What is stereotypy
A repetitive behaviour that shows no obvious benefit or result
What is a symbiotic relationship
An intimate relationship between two individuals of different species
If individuals in a symbiotic relationship depend on one another and have spent a long time in this bond, they have…
Co-evolved
What are two categories of symbiosis
+ parasitism
+ mutualism
Describe parasitism
When one organism (the parasite) gains nutrients from another host organism - harming it in the process
Why must parasites bind to high-energy organisms
As they have naturally low metabolisms
Give an example of a parasitic relationship
Head lice and humans, as the lice feed off of the human individual’s blood
Name the three ways that a parasite may be transferred between hosts
+ direct contact
+ release of resistant stages
+ use of a vector
What is direct contact
When two host individuals come into physical contact with one another, allowing the parasite to transfer - whilst they are conjoined
What are resistant stages
Period in the parasite’s lifecycle when it is resistant to certain extremities, such as heat or acidity.In addition, it may be able to survive out-with the host’s body - increasing the chance of transmission.
What is a vector
An organism that a parasite uses to move between hosts, as it latches onto it.
Give an example of a vector
The anopheles mosquito
This carries the malaria-causing plasmodium parasite between human hosts, injecting it into their bloodstream
How can you tell if an organism is a parasite’s primary or secondary host
Primary host: The parasite can sexually reproduce within
Secondary host: The parasite undergoes reproduces asexually or through larval stages
What is mutualism
A symbiotic relationship, in which both involved individuals benefit - demonstrating interdependence.
Give an example of mutualism
Coral polyps and zooxanthellae algae
The coral provides the algae with carbon dioxide and a nitrogen-rich environment. The algae produces carbohydrates for the coral - through photosynthesis
What is the difference between DNA packaging in the nucleus and mitochondria/chloroplasts of eukaryotes
Nucleus = linear hormones, wrapped around histones
Mitochondria/chloroplast = circular chromosomes
What is a social organism
One that lives in a group of related individuals
Give two examples of complex group activities
Cooperative hunting - increases hunt success rate and share of food for members
Group defence - prevents predators from isolating members
What is a social hierarchy
An unspoken ranking system that categories each group member by their importance and authority
Give an example of a natural social hierarchy
The pecking order of domesticated hens
What are high-ranking members known as, in the hierarchy
Dominant members
What are low-ranking members known as, in the hierarchy
Subordinate members
What is appeasement behaviour
The non-offensive behaviour displayed by subordinates, in an attempt to display their obedience to dominant members. For example, shoulder-shrugging and head-ducking.
What is threat display behaviour
The offensive behaviour shown by dominant members, as they reinforce their authority over subordinates. For example, teeth baring and prolonged eye contact
What are both appeasement and threat display known as
Ritualistic behaviours
Why do members of social hierarchies carry out ritualistic behaviours
To reduce conflict and aggression
What is an alliance
A group of subordinate individuals who join together, as to increases their status within the social hierarchy
What is altruism
A social behaviour that benefits a recipient individual, but harms the donor. This decreases the survival chance of the donor, but boosts that of the recipient.
What is the term used when the roles of altruism are later reversed
Reciprocal altruism
What is kin selection
A form of altruism, where the donor helps a closely-related individual, in an attempt to increase the survival chance of their shared genes
Give an example of kin selection
Vampire bats sharing blood meals with their kin
Give an example of social insects
Bee colonies
What is the role of a queen bee, within the hive
They produce a supply of unfertilised eggs
What is the role of drones, within the hive
To fertilise the eggs that’s are laid by the queen bee
What are the roles of worker bees, within the hive
+ to raise the queen’s offspring (kin selection)
+ to defend the hive
+ to find food and direct the hive towards it (waggle dance)
What is biodiversity
The term used to describe the variation between all living organisms
What are the three components of biodiversity
+ genetic diversity
+ species diversity
+ ecosystem diversity
Define genetic diversity
The measure of the number and frequency of different alleles in a certain population
What are the two components of specie diversity
+ species richness
+ relative abundance
What is species richness
The measure of the number of different species, within a certain ecosystem
What is relative abundance
The proportion of each species in the ecosystem
Define ecosystem diversity
The number of individuals ecosystems, within a defined area
What is exploitation
The harvesting of natural resources at a sustainable rate, for the benefit of the harvester
What is overexploitation
When the resource is harvested at a greater rate than it is replaced or reproduced, meaning the population begins to decrease in ice. This leads to extinction.
What is a bottleneck effect
An event that causes a population to decrease in size considerably. This reduces the genetic diversity of the population, when they begin to reproduce again
What is habitat fragmentation
The formation of several smaller habitats, from one large one - with the total area of the habitats equating to less than that of the original.
What are the effects of habitat fragmentation
Species richness decreases, as there is less room to accommodate organisms
What are habitat corridors and how do they counteract the effect of habitat fragmentation
Natural links that conjoin the separates habitats
This increases the access to food sources and possible mates, as well as laying a foundation for later reconstruction of the original habitat.
What is a native species
One that naturally occurs in a particular ecosystem
What is an introduced species
A non-native species, which enters an ecosystem by intentional or non-intentional human activity
What is a naturalised species
A non-native species that establishes itself to the extent where it can reproduce species
What is an invasive species
A naturalised species that spreads rapidly and eliminates native species
What is the order of transformation, to create invasive species
Introduced —> Naturalised—> Invasive
Why are invasive species so successful in their new habitats
+ no natural predators, pathogens or parasites
+ they outcompete native species for resources
Give two examples of invasive species, within the UK
+ Giant hogweed
+ Japanese knotweed
