Biology- Sustainability & Interdependence

Why are crops more efficient to produce as a food source than livestock?

90% of energy is lost every time food is transferred from one organism to another, so crops produce more energy per unit of land

What are A and a genes called?

A- Dominant, masks the presence of a a- Recessive, needs two copies to be expressed

What are the two allele combinations?

AA/aa- Homozygus Aa- Heterozygus

What are the three fates of light hitting a leaf?

Absorbed and used for photosynthesis, reflected off, transmitted through

What are the two spectrums used to measure photosynthesis?

Absorption spectrum shows the wavelengths taken in by each pigment, action spectrum shows which of them were used most in photosynthesis

What are three ways viruses are transported?

Air, soil, organisms as vectors

What are different forms of genes called?

Alleles

What are the three main photosynthetic pigments and what colours do they absorb?

Chlorophyll A- Blue, red Chlorophyll B- Blue, red Carotenoids- Blue, green

Describe the benefits of living in a social group

Cooperative hunting- Predators kill larger animals, reduce energy usage per individual and benefit subordinate animals Cooperative defence- Safety in numbers, alarm calls, protect young

What are the two types of characteristics?

Discrete- Set characteristics eg. eye colour Continuous- Characteristics on a spectrum eg. height

How do you calculate the harvest index of crops?

Dry mass economic yield/Dry mass biological yield

Describe the two stages of photosynthesis

Energy Capture- This occurs in the granum of chloroplasts. The energy absorbed from light excites electrons in the pigment molecule, and these are passed through a series of electron carrier molecules and release energy which is used by ATP Synthase to make ATP. Some of the energy is also used to split water into hydrogen and oxygen through photolysis (o2 is released and H is taken to next stage by NADPH) Calvin Cycle- The ATP and NADPH diffuse into the stroma. The enzyme RuBisCo fixes Carbon Dioxide from the air by attaching it to RuBP to produce 3PG. ATP turns into ADP+Pi and NADPH into NADP to add phosphate and hydrogen to the 3PG making it G3P. G3P is used to regenerate RuBP for another cycle, and also brings about the synthesis and release of glucose- which can be stored as starch, used as cellulose for structure, used up as instant energy, or used to make amino acids

Describe the two types of symbiosis

Parasitism- One organism benefits by gaining energy and nutrients but the host is harmed through the loss of these resources. Parasites have limited metabolisms and can often not survive independently, so require secondary hosts to transport them. Parasites can be transported by direct contact, resistant stages or animal vectors eg. malaria and mosquitos Mutualism- Both organisms benefit from a relationship eg. cattle stomach bacteria get food and warm conditions and cows get their cellulose partially digested eg. mitochondria and chloroplasts and other small independent organelle were engulfed by larger cells and they got security and big cells got better energy output and food production

What are the names for an organism's physical characteristics and the alleles that make them up?

Phenotype, genotype

What are three traditional ways of controlling weeds?

Ploughing, weeding, crop rotation

How do you calculate and measure net assimilation?

Increase in mass of a plant due to photosynthesis - loss due to respiration (increase in dry mass per unit of leaf area)

Describe the three stages which occur as a new organism in a habitat becomes a threat

Introduced Species- Those moved by humans unintentionally or intentionally to a new non-native geographical area in which they cannot survive for long Naturalised Species- Introduced species which become established within wild communities and are able to live and breed successfully eg. UK apples Invasive Species- Naturalised species which spread rapidly because their new environment lacks predators and competitors, they eliminate native species through hunting them/spreading disease/competition eg. grey squirrel v red

What are the three reasons animals help each other?

Reciprocal behaviour- The donor harms itself to the benefit of the recipient in the hope that the process will be reversed when it is in need eg. bats sharing food after an unsuccessful hunt Kin selection- Animals help animals which are not their offspring but are related to them, to ensure their genes are passed on

Describe social hierarchy and how it is maintained

It is a system in which members of a social group are on a ranking. It allows for lowering of conflict an aggression, guaranteeing experienced leadership and passing on the most favourable genes. Relationships are maintained through grooming, facial expressions, body language and sexual presentation

What happens to light if it is absorbed by the leaf?

It is absorbed by photosynthetic pigments and used to generate ATP

What is food security and why is it an issue?

It is the ability of human populations to access food of sufficient quality and quantity to avoid malnutrition. The growing population has dramatically increased the demand for food, and as it continues to rise we need to develop ways of growing more food on the same amount of land in a way which does not harm the environment

What is climate change modelling and what are its challenges?

It is the use of technological modelling systems to forecast the effects of climate change in certain species or ecosystems to guide research or predict biodiversity in the future. It gives an incomplete understanding of the climate system, knowledge is not completely transformed into equations, computers have limited power, the representation of complex natural interconnections is often inaccurate, a model cannot completely recreate certain atmospheric phenomena

Describe integrated pest management

The combination of chemical and biological controls as well as traditional methods to reduce pest populations through control not eradication

What is the equivalent of inbreeding and outbreeding in plants?

Self-pollinating plants naturally inbreed but are not as susceptible to ID as deleterious sequences are eliminated by natural selection Cross-pollinating plants outbreed to produce genetically diverse populations where desired characteristics are naturally selected

What is it called when an animal with an unknown genotype is bred with an animal homozygous for a trait to find out its genotype?

Test cross

What are some disadvantages of chemical crop protection?

Toxicity to other animal species, persistence in the environment and accumulation in food chains eg. bioaccumulation of DDT affecting bird eggs, leading to the development of new resistant species

What is animal welfare and why is it important?

It is the wellbeing of animals who are able to grow, reproduce and be healthy and content. Cruelty is unethical, but animals are often raised in stressful and inadequate conditions for the production of cheap food. Indicators of poor animal welfare include stereotypy (repetitive movements), misdirected behaviours, sexual/parental failures and altered levels of activity. If animals are treated well they produce products of a higher quality which can be sold for a higher price.

Name four factors which affect food production and how we can control them

Lack of nutrients in soil- Fertilisers Wrong temperature- Polly tunnels Pests harming crops- Pesticides, biological control Diseases- GM crops, fungicides

What are three types of pest?

Nematodes (worms), molluscs (snails), insects

What are true breeding animals?

Ones which always pass on the same characteristics to their offspring

What is the difference between outbreeding and inbreeding?

Outbreeding- When unrelated individuals mate, reducing harmful deleterious genotypes by increasing diversity in the population Inbreeding- When closely related individuals mate, often resulting in Inbreeding Depression (reduced fitness and vigour in offspring due to the accumulation of harmful homozygous recessive alleles

Describe three human threats to biodiversity and how they can be reduced

Overexploitation- Humans continuing to utilise a resource after it begins to reduce eg. overhunting, overfishing (can be reduced by quotas and regulation) Deforestation- The destruction of habitats and quickening of global warming through reducing tree photosynthesis Habitat Fragmentation- Breaking down of large habitats into smaller areas by building roads etc, less species are supported by the smaller area, habitat degredation can decrease the quality of an area and cause species to invade other habitats, interior species suffer most as edge increases (can be reduced by habitat corridors to link habitats)

What is the photosynthesis equation?

co2 + H2o (Light + Chlorophyll) = Glucose + o2

What are the five ways climate change decreases biodiversity?

Changing the distribution and abundance of species, changing the timing of seasonal events eg. migration, changing the composition of plant and animal communities, the loss of habitats eg. melting ice caps, increase in sea temperatures

Define symbiosis

An intimate relationship between two organisms of different species which has evolved over a long period of time

What is a weed?

An unwanted plant which grows among crops and causes a reduction in their productivity by competing for nutrients or otherwise harming them

Describe the two types of weeds

Annual- Complete short life cycle in one year, grow quickly, rapidly produce flowers, produce vast numbers of seeds which remain dormant and viable for long periods of time Perennial- Life cycle over many years, already established at the start of each growing season because it has food reserved in a storage organ, reproduces vegetatively (one parent only) using structures like runners and bulbs

What is the difference between biological and economic yield?

Biological yield- Total biomass of all crop parts Economic yield- Total biomass of desired product

What is the study of animal behaviour called and what does it involve?

Ethology involves the observation of animals in their natural habitats to establish how they behave in ideal conditions. Preference tests (controlled choices) and motivation measures (animals driven in meeting their needs) are also used to produce an ethogram with results

What is the difference between extinction and mass extinction?

Extinction is the natural dying out of species and their replacement by others. Mass extinction is when many die at the same time because of a significant change in the environment on earth eg. asteroids, climate change. There have been five such occurrences so far. Biodiversity is regained through evolution of survivors by speciation to fill all the available niches- adaptive radiation.

What are F1 and F2 hybrids?

F1- Produced by the crossing of two different inbred lines to create a uniform heterozygous crop with improved vigour and yield F2- Second generation hybrids varied in genotype and likely to suffer from ID

What three things cause disease?

Fungi, bacteria, viruses

What are the two processes in genetic technology?

Genetic Sequencing- Identifying the genes Genetic Transformation- Improving organisms eg. golden rice with vitamin a

Describe the three main components of biodiversity

Genetic diversity- Genetic variation in species (number and frequency of alleles in a population) Species diversity- The number of species and their relative abundance in an ecosystem (communities with a dominant species have lower species diversity) Ecosystem diversity- The number of distinct ecosystems within a defined area (good ones include marine, desert, tundra)

Describe the three chemicals used for crop protection

Herbicides- Kill weeds systematically by being absorbed into their circulatory systems or selectively by mimicking natural plant hormones causing rapid growth, depletion of resources and death Insecticides- Kill insects systematically by being absorbed into plants and making them poisonous when eaten Fungicides- Kill fungal parasites systematically by spreading through plants as protective agents

What is artificial selection?

The evolution of a wide variety of crops and domestic animals through selective breeding and hybridisation

Define photosynthesis

The process by which green plants trap light energy and use it to produce carbohydrates

Define sustainability

The quality of not being harmful to the environment or depleting natural resources, and thereby supporting long-term ecological balance

What is plant productivity?

The rate of generation of new biomass per unit of area per unit of time

Describe biological control

The reduction of a pest population by the deliberate introduction of one of its natural enemies eg. predators, parasites, pathogens

Describe how primates differ from other species

Their young are born helpless and require long periods of parental care, which allows them to pick up complex behaviours. They make alliances and favour those individuals in leadership contests. Their behaviour is affected by the social structure, the taxonomic group, the ecological niche and the distribution of resources

Describe field trials?

They are carried out in a variety of environments to compare the performance of different varieties of crops or different treatments. To ensure they are fair the plots have to be replicated a number of times and the varieties have to be randomly spread

Why are accessory pigments important?

They extend the range of wavelengths of light the plant can use for photosynthesis and mean the plant can access the energy required for photosynthesis with a variety of different lights present

Describe keystone species and their importance in ecosystems

They include ants, bees, wasps and termites. They live in complex colonies where only one individual carries out reproduction and the other sterile individuals care for her and collect food. This division of labour increases species survival chances, and is an example of kin selection. They are decomposers, pollinators, predators, prey and habitat builders, so their loss can collapse ecosystems