Genetics, Populations, Evolution And Ecosystems Flashcards
Define genotype
An organisms genetic composition
Define phenotype
An organisms characteristics, which occurs as a result of both its genotype and the impact of the environment
What is an allele?
Alternative forms of a particular gene with different base sequences and therefore different codes
What are the four types of alleles?
Dominant
Recessive
Co-dominant
Multiple alleles
What is the difference between diploid and haploid cells?
Haploid cells contain only one set of chromosomes (half set -23) and diploid cells chromosomes occur in pairs (full set -46)
What are heterozygous cells?
Organisms in which paired alleles are different
E.G- Bb
What are homozygous cells?
Organisms in which paired alleles are the same.
E.G- BB or bb
Define monohybrid inheritance
Inheritance of a single pair of alleles- only one from each gamete (due to meiosis)
Define dihybrid inheritance
Inheritance of two different characteristics simultaneously
What is an autosome?
Chromosomes numbered (1-22) which are known as body cells not sex cells
State the difference between sex-linkage and autosomal linkage
Sex linkage occurs when there is a gene on the X chromosome, not present on the Y chromosome.
Whereas autosomal linkage occurs if two or more genes are located on the same autosome(non-sex chromosomes)
What is a species?
A group of organisms that can successfully interbreed
Define population
Members of the same species living in one habitat
Define gene pool
Complete range of alleles in a population
Define allele frequency
Relative frequency of a particular allele in a population
What is the hardy-Weinberg principle?
Explain the hardy-Weinberg equation for calculating allele frequency
Explain the hardy-weinberg equation to calculating genotype frequency
What are the conditions under which the Hardy- Weinberg principle equation applies?
What two factors affect variation?
What is the primary source of genetic variation?
What is natural selection?
What is stabilising selection?
What is directional selection?
What is disruptive selection?
What is evolution?
Define genetic drift
Now does natural selection cause a change in a populations gene pool?
Why does genetic drift affect smaller populations more than larger ones?
Define community
Define ecosystem
Define biotic and give examples
Define abiotic and give examples
Define niche
Define habitat
What is meant by ‘carrying capacity’?
List four abiotic factors that affect population growth
What is meant by intraspecific and interspecific competition?
What are the two ways in which size of a population can be estimated?
How can quadrants be used for estimating population size?
How is mark-release- recapture used for estimating population size?
What is the equation for mark -release -recapture?
What are the assumptions made by the mark-release-recapture method?
Why are ecosystem described as being ‘dynamic’?
What is primary succession?
Summarise the process of primary succession
Define conservation
How might succession be managed in order to help conservation?
What is a dominant allele?
What is a recessive allele?
What are co-dominant alleles?
