ecology Flashcards
What is the (new) minimum number of quadrats that should be used when taking an estimation of a species?
20+
How does a new species arise potentially from two separate species?
1- GEOGRAPHICAL isolation
2-separate GENE POOLS ( lack of GENE FLOW)
3-variation due to MUTATION
4-different selection pressures
5-different reproductive success
6- change in ALLELE frequency
describe a capture-recapture method:
1-capture sample, mark AND release
2-method of marking cannot harm animal or reduce its chance of survival
3-leave for sufficient time to randomly distribute into the area, then collect 2nd sample
4-population = (number in first sample x number in second sample) / number recaptured
What are the key words that need to be used when talking about succession?
-pioneer species die and change the ABIOTIC factors for primary colonisers
-primary colonisers live in a less HOSTILE environment
-climax community live in a more SUITABLE environment than before.
Nitrogen cycle
-ammonium ions converted to nitrite ions
-nitrite to nitrate ions (nitrification)
-nitrate either;
-becomes N2 gas via denitrification by anaerobic bacteria
-ammonium containing molecules in producers
-any N2 gas can undergo nitrogen fixation via aerobic bacteria to ammonium molecules in producers
-either then become amine groups in consumers or ammonium containing molecules in saprobionts
-then becomes ammonium ions in the groud via ammonification
Where does nitrogen fixation occur on a plant?
Root nodules (in legumes)
Describe the phosphate cycle:
-phosphate ions in plants, phosphate ions in mammals and phosphate ions in waste are all dissolved in oceans
-these phosphate ions then end up as phosphate in rocks via deposition .
Describe a method to estimate a number of organism in an area
-divide area into equal squares
-use random number generator to gain co-ordinates of at least 20 squares
-place quadrat and measure number of species (as percentage cover or observable number)
-record all data then take a mean value
-times mean value by number of squares
-if using percentage cover, add percentages then divide by number of squares
When would we use percentage cover of a quadrat vs observable numbers
-percentage cover for more continuous data i.e blades of beach grass
-actual discrete numbers for larger objects i.e barnacles
Why do we use a random number generator?
To avoid any form of bias
What is biomass?
The dry material in an organism
Reasons why energy in food chains arent 100% transferred between trophic levels
-metabolic processes such as heat use energy
-energy lost in faeces and urine
-not all parts of organism is consumed by other organism (i.e fox not eating the bones)
What is GPP and NPP and their equations
GPP: gross primary production, all of the energy made by all producers in a certain area at a certain time
NPP: remainder of the gross production after all the respiratory losses are accounted for
NPP = GPP - R
What is net production
Net production is the total chemical energy consumers store after energy losses to faeces, urine and respiration have been taken away from the chemical energy store of the ingested plant food
-N = I - (F+R)
what is an ecological niche
-The role of an organism in its environment
-organisms with the same niche will be in competition
what is biodiversity
-the variety of living organisms in an environment
what impact does agriculture have on species diversity
-decreases species richness
-use of pesticides/herbicides
what impact does agriculture have on genetic diversity
-decreases genetic diversity
-farmers select for certain characteristics , which reduces number of different alleles in the population
how can biodiversity be increased in areas of agriculture
-use hedgerows instead of fences
-grow different crops in the same area
-limit use of pesticides and herbicides
what is the difference between intraspecific and interspecific competition
-interspecific competition is between different species
-intraspecific competition is between organisms of the same species
what is sampling
-selecting a group of individuals to measure that represent a whole population
Name types of speciation
-allopatric, geographical separation i.e flood
-sympatric, slight variation in phenotype
-hybrid sterility, gamete fusion produces odd number of chromosomes
-gametric, gametes stopped from combining
-temporal, breeding seasons don’t overlap
what is mycorrhizal fungi and what is its function
- a fungus that increases the surface area of root systems, helps increase uptake of water and mineral ions
what kind of relationship is shown between plants and mycorrhizal fungi and explain the relationship
-symbiotic relationship
-the plant receives more minerals and water
-the fungus receives organic compounds (eg glucose)
