Inheritance and Adaptations Flashcards
what is responsible for sex determination
make chromosomes (XY)
What makes a female
XX
What are the causes of variation
A foetus inherits characteristics from both parents (23 chromosomes from each)
Types of variation
Discrete - single gene controlled
Continuous - multiple gene controlled
another name for continuous inheritance
polygenic inheritance
Phenotypes
The physical appearance of an organism
Genotype
Range of possible phenotypes which are due to the particular alleles the organism has
Plant reproductive cells
Ovary and Anther
Plant cell gametes
Pollen Grain and Ovule
Species
a group of organisms that are so similar to each other that they can interbreed and produce fertile offspring
alleles
form of a gene eg red or white flower
make a protein of a specific type
Different types of mutation
Advantageous
Disadvantageous
Neutral
What are mutations
A rare and random change to genetic material. Only source of new alleles
Adaptations types
behavioural
physiological
structural
what are adaptations
characteristics possessed by an organism that makes it well suited to its environment or niche.
kangaroo rat
Homozygous
AA or as
heterozygous
Aa
Inheritance (2 types)
Recessive and Dominant
Why are observed and predicted genotypes not always correct?
Because fertilisation is a random process
Speciation
1 Population is isolated
2 Population are subjected to mutations
3 Each sub-population face different selective pressures
4 Some mutations are advantageous
5 The mutations stick because those without the mutations die off
6 Over many generations the genotypes change and become different species (when reintroduced they can not reproduce)
Evolution
a process by which species gradually change over time
Isolating mechanisms
Geographical
Ecological
Reproductive
Selective pressures
Something that causes issues with living in an area (predation, temperature)
Selective advantage
Something that helps an organism survive the selective pressures (colour of coat, no fur, lots of fur etc)
