Genetics, populations, evolution and ecosystems Flashcards
a habitat is
a place where an organism lives
a population is
all the organisms of one species in a habitat at the same time
a community is
all the populations of different species living in the same place at the same time
a niche is
role of a species within its habitat
an ecosystem is
a community, plus all abiotic conditions of their environment
carrying capacity is
the max stable population an ecosystem can support
result of interspecific competition
reduces resources available to both, limits both populations
a better adapted species will out compete the other
result of intraspecific competition
smaller population means less competition, which is better for growth and reproduction
larger populations is opposite and leads to smaller population
result of predation
increased predator population, more prey eaten, prey population. falls, less food for predators, predator population size falls, prey population rises
Randomly placed quadrats
-Split area into squares
-Obtain random coordinates using random number generator- place quadrats
-Count frequency of species in quadrat
-Calculate mean per quadrat
-Multiply mean by number of quadrats that would cover the area
Quadrats along a transect
-Lay tape measure from one place to another
-Place quadrants at regular intervals along the line
-Count frequency in cover
-Measures change in distribution
How to obtain valid results for capture recapture
-Mark must not be removed
-Mark should not affect survival/predation
-The duration of the sampling should be enough to allow mixing with the population
-NO due births
-No immigration
Steps of succession
-Colonisation by pioneer species
-Pioneer species change the abiotic conditions and make the environment less hostile
-Environment becomes more suitable for other species with different adaptations, and may be less suited for previous species
-Biodiversity increases
-Climax community: final, complex, stable community with no further changes
Conservation is
Protection and management of species and habitats sustainably
Conservation techniques
-Plants are covered using seed banks- seeds are stored
-Fishing quotas- to conserve fish species
-Endangered species are bred in captivity
Succession is
The process by which an ecosystem changes over time due to species presence.
What is a genotype
Genetic constitution of an organism
What is a phenotype
The expression of this genetic constitution and its interaction with the environment
What is an allele
Different version of a gene
What are forms of alleles in heterozygous state
-Dominant; allele that is expressed
-Recessive; allele that isn’t expressed
-Codominant; both alleles for same gene contribute to the phenotype
What is monogenic inheritance
Inheritance of characteristic controlled by a single gene
What are dihybrid crosses
Inheritance of two different characteristics controlled by two different genes
Dominance hierarchy
There may be more that 2 alleles in a population, however individuals only have 2 alleles of a gene
Where do sex linkages arise from and what are they
A gene is sex linked if its locus is on a. sex chromosome, and a specific characteristic is more likely to be inherited in either male or female offspring (genes most likely to be found on X chromosome)
Why is it more likely that males show recessive phenotypes than females
Only have one X chromosome, and they often only have one allele for sex linked genes so they express the characteristic of this allele even if its recessive.
Females have two alleles and only express the recessive if its homozygous recessive
What is an autosome
Non sex chromosome
