B16 Flashcards
Adaptations, interdependence and competition
What is an ecosystem ?
The interaction of a community of living organisms with the abiotic (non-living) factors of their environment
What is a community ?
All the populations of all the different species of animals, plants, archaea, protists, fungi and bacteria (biotic factors of an ecosystem) that are interdependent within a habitat
What is interdependence ?
The reliance between species on each other to provide food, shelter, seed dispersal, pollination etc.
- if one of these species are removed or grow drastically in number, it can affect the whole community
When is a community stable ?
When all species and environmental factors are in relative balance so that population sizes remain relatively constant overall
Name the key abiotic factors in an ecosystem that may affect communities (and why they might)
- light intensity
[] plants need light for photosynthesis, so will grow more in areas with more light
[] affects distribution of plants, and in turn the animals that eat the plants, and the animals that eat those animals and so on - temperature
[] temperature affects the rate of photosynthesis and thus affects growth and size of plants
[] if the growth/size of plants is negatively affected, the number of herbivores in a population will decrease due to the food scarcity and so will the carnivores in turn
[] opposite happens if positively affected - moisture levels
[] water needed for photosynthesis and life in general - soil pH/mineral content
[] affects distribution of plants and thus primary, secondary and tertiary consumers - wind intensity/direction
[] affects transpiration rates of plants and the shape of the environment - availability of (dissolved) oxygen (in water)
- availability of carbon dioxide
[] affects photosynthesis
Name the key biotic factors in an ecosystem that may affect communities (and why they might)
- availability of food
- introduction of new (strains of) pathogens or parasites
- introduction of new predators who can outcompete the native ones
- interspecific competition for resources etc.
[] esp. between invasive and native species
Describe a method using quantitative sampling to determine the approximate population size of an organism (usually a plant or a slow moving organism like snails, corals or anemones) in an area
- gather equipment
[] pen + paper to record results
[] quadrat with an area of 1 m^2
[] area to gather sample data in
[] trundle wheel - go to the area you want to sample in
- measure the length and width of the area in metres using a trundle wheel
- split the area into an imaginary grid where each “box” is 1 metre squared and is representative of 1 coordinate
- use a random coordinate generator to generate a coordinate
- place the quadrat on the coordinate generated
- count the number of organisms selected to study within the quadrat and record
- repeat this process as many times as possible (around 10% of the total area should be sampled), using the same size quadrat for every measurement
- calculate the mean number of organisms per metre squared to determine an approximation of the population size in a metre squared of the area, then multiply by the total area to approximate the total population size in that area
NOTE: this method can also be used to investigate the changes in distribution of organisms over time if repeated at regular intervals of time (eg. once every week for 12 weeks)
Describe how to use a transect and quadrat to investigate the change in distribution (population density) of an organism in relation to a certain factor, like light intensity
- select an area with lots of gradual variation in light intensity
- lay a tape measure (10m) along the area being sampled (making sure there is variation in light intensity along the tape measure)
- using a 1 m^2 quadrat, sample the organism selected and record results
- repeat 10 times in total to cover the full length of the tape measure/transect
- draw conclusions about the population density in relation to the decrease/increase of light intensity
What do animals compete for ?
- food
- shelter/territory
- mates
How are herbivores more likely to survive competition for food ?
Being able to eat a wide range of plants
[] those who can only eat certain types are more prone to extinction/population falls if the food source is high in demand (out-competition) or if it is removed from the area
How are predators and prey more likely to survive competition for food (for prey, in terms of being hunted) ?
predators:
- adaptations that make them well-suited to catching prey
prey:
- adaptations that make them efficient at avoiding capture, or make them dangerous to eat and thus not a viable food source for predators (like poisons)
Why are territories important to animals ?
- secures the individual’s space
[] reduces competition for food within the territory, as well as for shelter and space for raising young safely - animals mark territory using urine or dung oftentimes
How can an animal be a successful competitor ?
- being better adapted to finding food, territory and mates than other members of its own species or across species
- avoiding direct competition for food and territory with other species
[] eg. having a highly specialised diet which means that only members of that species will eat those foods, so competition is reduced
What do plants compete for ?
- light
- nutrients in the soil
- water
- space
Which behaviours generally make plants good competitors for light, nutrients, space and water
- large, broad leaves to absorb as much light as possible
- spreading seeds very far away so don’t compete with offspring via wind, water or animal vectors
- producing chemicals to kill nearby plants
- flowering and reproducing early in the year/at a time where not many other plants flower/reproduce
- very shallow or very deep roots
etc.
What are extremophiles ?
- mainly microorganisms like archaea but not limited to them
- adapted to survive in environments that have extreme conditions
[] extreme saltiness (some have adapted cytoplasms with higher ion concentration so that they don’t lose water via osmosis
[] extreme pressure
[] extreme temperature
[] extreme acidic/alkaline conditions
How are epiphytes adapted to survive in crowded rainforests ?
- live high above ground attached to other plants
[] maximum light availability - collect water and nutrients from air + in specially adapted leaves
How are saguaro cacti adapted to reproduce via bats ?
- flowers open at night when bats are most active
[] produce strong smelling nectar to attract bats
[] open at the top of the plant to make it easier for bats to feed from them
What are the main types of animal adaptations ?
- structural adaptations
[] shape + colour etc. - behavioural adaptations
[] migration, hibernation, tools etc. - functional adaptations
[] related to processes like metabolism + reproduction
[] antifreeze in cells, delayed embryo implantation etc.
What are some of the key adaptations of animals in cold climates ?
- smaller surface area to volume ratio to decrease how much internal heat is lost
- smaller thin-skinned areas of the body like ears to prevent too much heat loss
- insulation via thick fur and blubber
- some animals have antifreeze in their cells to prevent water in cells from freezing and destroying the cells
- different coat colours throughout the year for effective camoflague year-round
What are some of the key adaptations of animals in dry, hot climates ?
- functional adaptations in the kidneys to produce conc. urine and prevent water loss
- large surface area:volume ratios to cool down effectively without having to sweat and lose water
- most active at night or early morning when it is cooler
- smaller animals have burrows underground where it is cooler
- large thin ears to maximise heat loss
What are some of the key adaptations of plants in dry, hot climates ?
- reducing surface area to reduce rate of transpiration
[] curled leaves (also traps layer of moist air around leaf) - fleshy leaves with thick waxy cuticle to reduce rate of transpiration
- cacti’s spines are their leaves
[] deterrent for predators
[] very small surface area to reduce rate of transpiration - broad leaves to collect dew and funnel it towards stems
- roots that spread over a very wide area and/or very deeply to draw up as much water as possible
- storing water in fleshy leaves, stems or roots when it does suddenly become available
