YR 9 - Genetics and Inheritance Flashcards
what are chromosomes?
chromosomes are structures found in the cell’s nucleus that’s made of DNA.
what does DNA stand for?
DeoxyriboNucleic Acid
what is DNA?
DNA is a chemical code that contains instructions called genes.
what is a gene?
a gene is a section of DNA that carries the code for a particular protein.
what are alleles?
alleles are different forms of the same gene.
what are dominant alleles?
the dominant allele is the allele of a characteristic that is always expressed in an organism.
what are recessive alleles?
the recessive allele is the allele whose characteristics is only expressed in if the allele is inheritanced from both your parents
what is genetic variation?
genetic variation is the inheritance of different combinations of genes & alleles that controls the development of different characteristics.
(the difference in DNA among individuals)
what are phenotypes?
the phenotype is the physical appearance of characteristics e.g. dimples or no dimples
what are genotypes?
genotype is the genetic make-up of an individual.
how can a person be heterozygous?
a person is heterozygous for a trait if they have two different alleles.
how can a person be homozygous?
a person is homozygous for a trait if they have two of the same alleles.
what is monohybrid inheritance?
monohybrid inheritance is the inheritance of a single characteristic controlled by a pair of allele.
what is fertilisation?
fertilisation is the fusion of male and female gamete (sperm and egg cell)
what is a zygote?
a zygote is the fertilised egg.
what happens in natural selection?
in natural selection, individuals in a species show a wide range of variation due to differences in the gene.
what is natural selection?
natural selection is when individuals with characteristics most suited to their environment are more likely to reproduce and survive.
— the genes that allowed them to be successful are then passed on to their offspring.
what is variation?
variation is all the differences which exists between members of the same species.
how can variation be caused?
variation can be caused by the environment, genetics or by both.
what are the types of variations?
the two types of variation are continuous and discontinuous.
what is discontinuous (discrete) data?
discontinuous data is presented as a finite number that can be counted - the units of measure cannot be split.
what is continuous data?
continuous data is presented as an infinite amount of possible values that can be measured - there is a scale of measurement.
what are some examples of discontinuous (discrete) data?
• shoe sizes
• result of rolling a die
• number of orients in a hospital
• population of a country
• number of books checked out of a library
what are examples of continuous data?
• weight
• height
• length
• time
• temperature
what is competition?
competition is when animals and plants have to compete for limited resources.
• the best adapted animals or plants will win and survive.
what do plants compete for?
plants compete for:
• water
• light
• space
• minerals from the soil
what do animals compete for?
animals compete for:
• territory
• mates
• food
• shelter
what is adaptation?
adaptation is the features or characteristics of an animal or plant that allow it to live successfully in its habitat.
what causes adaptations?
adaptations are caused by changes to the environment surrounding an organism over time to aid survival.
Define:
Physical adaptations
A physical adaptations is a changing feature of a living thing that helps it to survive in a particular environment
• usually happens very gradually over generations (years)
e.g., different patterns or colours
Define:
Behavioural adaptations
A behavioural adaptation is a thing that an organism does to survive in a particular environment
e.g., the way they feed, breed or move
Define:
Extinction
extinction is when there are no more living members of an individual species.
Define:
Critically endangered
critically endangered is when there is an extremely high risk of extinction in the wild.
