Populations and ecosystems/speciation Flashcards
Species definition
2 species are able to interbreed to produce fertile offspring
Niche definition
The role of a species in its ecosystem and how interacts with all the biotic and abiotic factors
Hierarchy definition
Smaller groups within larger groups with NO overlaps
What is each group in a hierarchy called?
Taxon
What is the anagram for the classifications system?
Decide, King Prawn Curry Or Fat Greasy Sausage
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
What are the 3 domains organisms are sorted into?
- Eukaryota
- Bacteria
- Archaea
What are 3 difficulties in defining species?
- Can change and evolve over time
- Can be considerable variation within a species
- Many species are extinct and haven’t left a fossil record
How are isolated organisms tested for being in the same species?
By their ability to interbreed and produce FERTILE offspring
How are species named?
Genus species (genus always starts with a capital letter, species never starts with a capital letter) e.g. Homo sapiens
What is one way that different species can be distinguished?
Courtship behaviour (species-specific)
How can DNA/mRNA be used to classify species?
Closely-related species will have a higher % of similarities in DNA base sequence –> DNA hybridisation (one strand from one species, other strand from the other species, more hydrogen bonds formed = more closely related)
How can proteins be used to classify species?
Related organisms have similar DNA base sequences so similar amino acid sequences in their proteins
How can the immunological comparisons of proteins be used to classify proteins?
Greater the number of similar antigens = more precipitate formed = more closely related
Biodiversity definition
Variety of living organisms in an area
Community definition
All the populations of different species in a habitat
Habitat definition
The place where an organism lives
What does species richness measure?
The number of different species in a community
What does index of diversity measure?
The number of species and number of individuals in each species within a community (higher value = more biodiversity)
How does clearing woodland reduce biodiversity?
Reduces variety of plant species, reduces variety of habitats and food sources, reduces variety of birds/fish/animals
How does monoculture (single type of plant growing in a field) reduce biodiversity?
Reduces variety of food sources and habitats for organisms
What is carrying capacity?
Maximum population size of a species an ecosystem can support
What are abiotic factors?
Non-living e.g. pH, nitrates
What are biotic factors?
Living e.g. disease, predation, competition, prey
What is intraspecific competition?
Between members of the SAME species
What is interspecific competition?
Between members of DIFFERENT species
What happens if 2 species occupy the same niche?
One will out-compete the other
Succession definition
Gradual replacement of one plant community by another over a period of time, through a series of seral stages, starting with the pioneer community and ending with the climax community
What is primary and secondary succession?
Primary - original area has no soils/organisms
Secondary - following disturbance, soil is present
How does succession occur?
- Pioneer species survive in hostile conditions
- Change the abiotic conditions to become less hostile and more suitable
- New species colonise which are better adapted
- Out-compete pioneer species
- Over time species diversity increases and conditions less hostile
- Ends with climax community
What is a plagioclimax community?
Deflected climax community due to human activity
What is speciation?
Genetic differences in one population lead to an inability of members of the population to interbreed and produce fertile offspring
What is the anagram for allopatric speciation?
GAMASSRIFTS
Geographically isolated
Abiotic conditions are different
Mutations
Advantageous alleles
Selective pressure
Survive
Reproduce
Inherit alleles
Frequency of allele increases
Time (many generations)
Species can’t interbreed to produce fertile offspring
What is sympatric speciation?
Occurs within the SAME environment, by chance some organisms have mutations which give different alleles, separates gene pools, over time too genetically different to interbreed and produce fertile offspring, DISRUPTIVE selection
What is genetic drift?
Changes in allele frequency in SMALL populations (have smaller gene pool, by CHANCE one allele becomes more frequent than another)
How do you know how many quadrats to use to get representative data when random sampling?
Calculate a running mean until the mean becomes constant
What is the 5-step method for random sampling with quadrats?
- Use random number table to randomly select co-ordinates to take samples at
- Set up 10x10m grid
- Place quadrat at first co-ordinate and record number of ___ in quadrat
- Repeat step 3 at different co-ordinates until running mean becomes constant
- Multiply mean by number of times quadrat fits into the area
What is the 5-step method for systematic sampling with belt transects?
- Place multiple parallel transects ___
- Choose transect randomly using random number generator
- Place quadrats at regular intervals
- Measure % cover of each species
- Repeat with parallel transects
What are the 3 assumptions made with Mark, Release, Recapture?
- Birth rate = death rate
- No immigration/emigration
- Marking doesn’t affect survival
What is the equation for calculating estimated population size for Mark, Release, Recapture?
(number in first sample x number in second sample) / number of marked in second sample
What is the 5-step method for Mark, Release, Recapture?
- Set up a trap somewhere ___
- Record number of ___ captured and mark them in a way which doesn’t affect survival
- Release marked ___ and leave enough time for ___ to evenly mix with rest of population
- Set up trap again and record number of marked ___ in second sample
- Equation
