C4 Flashcards
What is a population?
An interacting group of organisms of the same species living in an area. Must be able to successfully breed.
What is a population size?
Number or estimated number of organisms in a population AT ONE TIME- constantly changing
What is a random sample?
A sample taken from an arbritrarily chosen zone, instead of using a predictable pattern.
What is a sampling error?
The difference between the estimated population size (from sample) and the real population size (difficult to quantify)
What is quadrat sampling?
Using a square of a particular dimension placed at a random location in the area. Organisms inside quadrant are counted. Useful for sessile organisms that cannot move.
Explain the process of quadrat sampling
- Put a measuring tape down along one or two edges of the target area
- Generate random numbers within the measuring units along transect
- First number determines the distance along transect
- Second number determines vertical distance
- Place a quadrat at that intersection
- Count every organism completely in quadrant
- Repeat and then multiply the sampled area to represent total area
What does the standard deviation tell us about the spread of the population?
Whether they are very spread out (large standard deviation) and occupy lots of area, or condensed in a small, specific area (small standard deviation)
Explain the process of capture-mark-release-recapture for motile organisms?
- In area, capture as many organisms with net, trap etc
- Mark each organism (mark must be non-toxic, non-washable and low visibility)
- Release organisms and wait (no-one dies, no one leaves/ comes and no marks dissolve)
- Recapture as many as possible (same #)
- Plug numbers into Lincoln Index
- High percent of recaptured are marked= smaller population size
What is the Lincoln Index and what do the letters represent?
P= N1xN2/R
P= Population size
N1= Size of first sample
N2= Size of second sample
R= Number of recaptures in the second sample
What is carrying capacity?
The maximum number of organisms that an environment can consistently meet the needs of
What is a limiting factor?
Any aspect or event that prevents a population from continuing to grow faster. Can also be something in finite availability that is needed for survival for many individuals in the community
Often gives rise to inter and intra specific competition
What is the difference between density dependent and density independent factors?
- Density dependent: factor that is much more significant or problematic in larger populations
- Density independent: factors that are unrelated/ not impacted by population size
What are the different types of density dependent factors?
- More predators
- Competition for food, water and space
- Faster spread of pathogens and parasites
How does exponential growth work- bacteria can do this?
- Both size and rate of growth continually increase due to abundant resources
- Use logarithmic scale on y-axis
- Only limiting factors are density independent factors- affect all populations no matter of size e.g natural disasters, climate change
- Can be caused by positive feedback loops which cause more growth
Explain the phases of a sigmoid growth curve.
- Exponential phase (rate increases)
- Transitional phase (size grows at a slower rate)
- Plateu phase (population stabilises at carrying capacity)- birth rate= death rate
* Population begins rapidly but rate of growth slows down until the size stabilises at carrying capacity
* Limited resources
* Impacted by independent factors but also density dependent factors
Bigger impact in crowded populations
Spread of disease, competition for food, water and shelter
Attract more predators
What is a community?
All of the populations in an area and their interactions e.g feeding, competition, and symbiotic relationships.
Can also be defined as the biotic factors of a habitat
What is herbivory?
An interspecific relationship where primary consumers feed on producers. Often does not kill producer, and can even be beneficial, but can sometimes kill small plants
What is predation?
Interspecific relationship involving one consumer species (predator) killing and eating another consumer species (prey). Necessary for population control
What is mutualism?
A type of symbiotic relationship where both species benefit from the relationship
What is a symbiotic relationship?
Ongoing close association between species
What is parasitism?
A type of symbiotic relationship where one organism (the parasite) lives on another organism (the host) and negatively affects them
What is pathogenicity?
Similar to parasitism, but causes disease to the host. Not usually ongoing, as the disease will kill organism or the organisms immune system will kill the pathogen
What is an endemic species?
A species that is naturally found in that area, a population in its natural habitat
What is an invasive species?
Alien species which rapidly reproduced and outcompeted endemic species. Have the threat to damage stable ecosystems
What is the difference between an interspecific and intraspecific relationship?
- Interspecific: between different species living in the same community
- Intraspecific: between members of the same species in a shared habitat
What are the types of intraspecific relationships
- Competition
- Cooperation
How does competition work in interspecific relationships?
Competition for a shared resource leads to competitive exclusion- elimination or niche partitioning
How does cooperation work in intraspecific relationships?
- Benefits all members
- Seen more in complex social animals (behavioural)
- Examples: huddling for warmth, pack hunting, schooling in fish, parenting young
How does competition work in intraspecific relationships?
- Live in the same niche
- When resources are limited, not all survive
- Drives natural selection, ensures survival of best adapted
- Stability at carrying capacity
- This results in a net positive for the population as only the best adapted survive
- Examples: Access to food, water and shelter
What are the types of interspecific relationships?
- Mutualism
- Competition
- Herbivory
- Predation
- Parasitism
- Pathogenicity
What are 3 examples of mutualism?
- Rhizobium bacteria grow in nodules in plant roots
- Micorrhizae fungi growing on roots (orchids)
- Zooxanthellae and coral polyps
Explain the mutualistic relationship between rhizobium bacteria grow in nodules in plant roots, and the benefits to each species.
Benefit to bacteria: sugar from plant photosynthesising, shelter/home on roots- protection from consumers
Benefit to plants: bacteria take N2 nitrogen from atmosphere and ‘fix’ it into ammonium and nitrates which plants can use
Explain the mutualistic relationship between mycorrhizae fungi and orchid roots, and the benefits to each species.
Benefit to fungi: sugar from plant photosynthesising
Benefit to orchids: fungi help absorb nitrogen, phosphorous, carbon compounds and water
Explain the mutualistic relationship between zooxanthellae and coral, and the benefits to each species.
Zooxanthellae: Home, protection from predators, closer to light, CO2 source from coral
Coral: sugar from photosynthesis
Explain the steps of a chi-squared test for association
- State the null and alternate hypothesis
H0= The species are distributed independently
H1= There is an association between the two species - Make a contingency table for observed data
- Use the contingency table to calculate expected values
Expected= row total x column total/ TOTAL - Create a table to calculate chi square values
(O-E)^2/ E
Then add them all together- sum of all is the chi squared value - Compare chi square value to a critical value
degrees of freedom (df) = 1
probability (p value)= 0.05 - Make a conclusion
- If chi squared value is greater than critical value- reject the H0
- If chi squared value is smaller than critical value- fail to reject the H0
What are antibiotics?
Secondary metabolites (not made for life functions but to release into the environment). In antibiotics, the chemicals released by one organism kill/ inhibit the growth of nearby bacteria
What is allelopathy?
The release of chemicals/ secondary metabolites into the environment that impacts another organism. Impact is often harmful which provides a competitive advantage.
What is cyclical oscillation in predator and prey relationships?
As both act as density dependent factors to each other, it creates a cycle where:
* Increase in prey= increase in predators
* Increase in predators= decrease in prey
* Decrease in prey= decrease in predators
* Decrease in predators= increase in prey
Cycle restarts
What is the difference between top-down and bottom-up population control?
- Top down- higher trophic levels impact population of lower ones
- Bottom up- lower trophic levels impact the population of higher ones
What is the difference between primary and secondary metabolites?
- Primary- neccessary for the basic functions of life
- Secondary- only made by certain organisms, are non-essential but often help the organism obtain food or avoid predation
What is the first law of thermodynamics?
The Law of Conservation of Mass- energy can neither be created or destroyed- only change forms
What is the second law of thermodynamics?
When energy is transferred into another form, it often becomes a less useable form
What is a producer?
Photo/chemo synthetic organisms that create carbohydrates which fuel the ecosystem through inorganic sources e.g sun, water, CO2
What is a consumer?
An organism that obtains energy from the carbon compounds on which they feed, a subset of heterotrophs which directly transfer energy in the ecosystem
What is a decomposer?
An organism that releases enzymes into the environment to break down unconsumable parts by consumers. Provides energy for them but also returns nutrients to the soil
What are trophic levels?
An indication of how many organisms in an ecosystem energy has flowed through.
Producers– Primary Consumers– Secondary Consumers etc
Explain the difference between an open and closed system
- Open ecosystems- involve the movement of new matter in and out e.g water, populations
- Closed ecosystems- only allow movement of energy
What is the difference between a primary, secondary and tertiary consumer?
- Primary consumer- eats producer
- Secondary consumer- eats primary consumer
- Tertiary consumer- eats secondary consumer
What is the difference between a food chain and web?
- Food chain- linear set of producer to consumer
- Food web- shows all the interlinking food chains, and the complex nature of feeding relationships
How do photoautotrophs and chemoautotrophs make organic energy sources?
- Photoautotrophs: light energy + water + CO2= glucose
- Chemoautotrophs: inorganic compounds e.g sulfur, iron + CO2= glucose
What is primary production?
The accumulation of carbon compounds in biomass by autotrophs
Gross primary production= all biomass
Net primary production= biomass available to consumers
What is secondary production?
The accumulation of carbon compounds in biomass by heterotrophs.
Gross= total
Net= amount available to next trophic level
What are the three main forms of energy loss between trophic levels?
- Incomplete consumption- not all parts of an organism are eaten e.g bones
- Incomplete digestion- not all parts of an organism are digested and absorbed e.g cellulose is passed in faeces
- Cellular respiration- Carbohydrates broken down and turned into ATP energy, which is then released as CO2 along with heat into atmosphere
Explain how heat is lost in organisms
- Process of carbon conversion to ATP is not 100% efficient, so heat is lost to the environment
- Heat is also lost during when ATP is used
- Heat is an unusable form of energy, but some heterotrophs have adaptations for increased heat production during respiration to maintain body heat
Why are food chains limited in their length?
A lot (90%) of energy is lost in between trophic level, so it is hard to sustain a large mass of apex predators or more than 4 trophic levels (max 6)
What are sources of energy loss between trophic levels?
- Used as ATP for movement and reproduction
- Lost as heat
- Lost as undigestable material
What happens to the approx. 10% of energy that transfers to the next trophic level?
Forms new body tissue that can be consumed and digested by the next trophic level
What is a carbon pool?
A reserve or storage of carbon e.g in the atmosphere, starches in roots, or the ocean (largest carbon pool).
What is a carbon sink?
A carbon pool that has the ability to take up more carbon than it releases
What is the process of carbon flux?
Carbon flux is the process that transfers carbon from one carbon pool to another. It occurs naturally, but also can be caused by human activities.
What are the three types of carbon fluxes due to living things?
- Photosynthesis- absorption of CO2 from air or water and conversion into organic carbon compounds
- Feeding- transfer of organic compounds from one organism to another
- Respiration- break down of glucose and release of carbon back into atmosphere as CO2
What determines whether an ecosystem acts as a carbon sink or a carbon source?
The balance between photosynthesis and respiration
* If photosynthesis is greater than respiration= net carbon uptake= carbon sink
* If respiration is greater than photosynthesis= net carbon release= carbon source
How was the carbon sink of natural gas and oil formed?
Deep burial of partially decomposed matter, increased temperatures cause chemical changes to produce oil and natural gas in porous rocks. Slow process
How was the carbon sink of coal formed?
Accumulation of wood and other plant matter in swamps buried by sediment. Formed starting 325-250 million years ago
How was the carbon sink of peat formed?
Incomplete decomposition of dead plant matter due to acidic and anaerobic conditions in waterlogged bogs and swamps. Formed in the past 10,000 years
How was the carbon sink of biomass formed?
Plant and animal biomass that stores carbon compounds from photosynthesis. Unconsumable plant and animal matter can be burned to produce energy
How does combustion impact the carbon cycle?
- Combustion= burning in air of any carbon sink to produce energy
- Normally requires temps higher than reached on earth, except when lightning occurs
- CO2 is a waste product of combustion
- Humans intentional burning of fossil fuels has significantly increased CO2 levels in the atmosphere
What are the different types of carbon compounds?
- CO2- gas in the atmosphere or dissolved in the ocean
- Organic compounds- solid, food e.g carbohydrates, fats and proteins
- Biomass- body parts of plants and animals (stored energy)
- Wastes and rots- undigested and uneaten biomass, waste and dead parts
- Fossil fuels- peat- turns into coal, oil and gas
Draw the terrestrial carbon cycle
See picture on phone
Draw the marine carbon cycle
Where has the data from the Keeling Curve come from?
Data for the Keeling curve has been gathered since 1959 on the CO2 concentration at the Mauna Loa Obervatory in Hawaii
What is the annual pattern of change in CO2 concentration and the cause of this?
- Decreases between May and October
- Coincides with summer in the Nothern Hemisphere
- More light= more photosynthesis= more use of CO2= less atmospheric CO2
What is the long-term trend of change in CO2 concentration and the cause of this?
- Increasing over time
- Increasing rate of increase gradually
- Caused by human activities e.g combustion, deforestation- increasing over time
What are some other elements that are cycled through ecosystems by living organisms?
- Hydrogen
- Oxygen
- Nitrogen
- Potassium
- Calcium
- Phosphorous
- Sodium
- Iron
