Definitions Flashcards
Species
Group of similar organism with the same genes that reproduce to produce fertile offspring
Population
All the individuals of a given species living together in the same area at the same time
Carrying Capacity
Maximum, equilibrium number of organisms of a particular species that can be supported in each stable environment. Birth rates and death rates are at equilibrium
Community
All the individuals of all the species living together in the same area at the same time
Habitat
Place where organisms live in an ecosystem
Niche
Describes where an organism lives and what it does, including what it feeds on and how it interacts with other organisms and the environment.
Why do two species not have the same niche?
They would compete and one would be more successful
What happens where niches overlap?
Species have adaptations that outcompete. Different organisms may operate the same ecological niche whilst competing until one is eliminated.
Types of quadrating
Density- actual count of all individuals- time consuming, most accurate, species may be difficult to count.
Percentage cover- area covered by one species is recorded as percentage of total area- used when there are too many individuals to count, over-laying species may occur
Frequency- proportion of quadrants that contain a particular species. Least accurate
Random quadrating method - how many should be used?
Map area using two measuring tapes, use random number generator to lay quadrat.
Stop when there is little change, enough to carry out a statistical test and calculate a running mean.
Systematic sampling
Transect- recording what touches the line at each point
Belt transect- two parallel lines, metre apart, record what’s found between the two lines.
Interrupted- one line, places quadrat at equally spaced sampling points and record abundance of species within quadrat,
Succession
Series of a change within a community. Starts from barren rock to climax community
Pioneer species
The organisms that first colonise an area
Sere
Complete succession from pioneer community to climax community, a seral stage has its own distinctive community of organisms.
Climax community
Final stage- stable, formed depending on abiotic factors
Hostility and abiotic environment / diversity
Low diversity and abiotic factors dominate the distribution of species
Non-living parts of the environment
Relationship between number of organisms and number of species within a community.
Process of succession
Colonisation by names pioneer
Change in environment
Enables other named species to colonise
Change in diversity
Stability increases
Climax community is represented by named species
Secondary succession- happens after a forest fire etc. begins with pioneer seres
Biodiversity
The number of species and the number of individuals of each of the different species within one community
Species richness
The number of different species within a community
Genetic diversity
Difference in DNA
Diversity
Index
N(N-1)/n(n-1)
What info is required to calculate an index diversity
Number of species, number of Individuals in a species
Explain why an index of diversity may be more of a useful measure of biodiversity
Also measures number of individuals of each species. Some species may be present in low/high numbers
2 advantages of using an index of biodiversity rather than an indicator species
Don’t need to identify each species, index considers number of organisms of each species
Economic arguments for maintaining biodiversity
High species diversity, the more stable the eco-system
Pharmaceutical use,commercial products, tourism, agriculture and saving local forest communities
Farming reduces species diversity
Natural plants etc lost when land is cleared, may reduce variety of food sources, habits and niches, growth of specific crops and growth of other species is controlled or stopped, pesticides etc are used to kill unwanted species.
Hierarchy
Domain, kingdom, phylum,class, order, family, genus, species
Phylogenetic vs binomial naming system
Bi= first word- genus name. Second word- species name
Ph- all organisms evolved from shared ancestors- more closely related.
Courtship behaviour and 2 ways it increases probability of successful mating
Attract a mate of the same species and opposite sex. Important to ensure reproductive success.
Attracts same species of opposite sex, indication of sexual maturity, stimulates release of gametes, form pair bond
Classification methods
Base sequence of DNA/ mRNA and amino acid sequence of the proteins
