Genetics and Variation - Half Term 1 (9Aa, 9Ab, 9Ac) Flashcards
What is environmental variation?
Variation caused by an organism’s surroundings, including abiotic factors (e.g. temperature, light) and biotic factors (e.g. competition, predators)
Examples:
- piercings, clothing, weight
What is genetic variation? (Also known as inherited variation)
Variation caused by an organism’s genes, passed down from the parents
Examples:
- hair colour
- eye shape
- blood group
What is a species?
A group of living organisms that can interbreed and produce fertile young/offspring
The surroundings of an organism are called its _______________
Environment
What are characteristics?
Distinctive biological traits or features of the organism
What is the difference between an environmental factor and a physical environmental factor?
An environmental factor can be abiotic or biotic, but a physical environmental factor can only be abiotic
What is a resource?
A substance or object in the environment required by an organism for normal growth, maintenance and reproduction
What is the environment?
All living and non-living elements by which an organism is surrounded
What is an abiotic factor?
Non-living part of an ecosystem that shapes its environment
What is a biotic factor?
A living organism that shapes its environment
What is continuous variation?
A characteristic that changes gradually over a range of values (e.g. height)
What is discontinuous variation?
A characteristic that comes in groups rather than a range (e.g. blood group)
What is classification?
The process of arranging organisms into groups based on similar characteristics
How should discontinuous variation be shown in a graph?
- bar chart
- spaces in between the bars
- no ‘normal distribution’ curve
- group along x axis
How should continuous variation be shown in a graph?
- histogram
- no spaces in between the bars
- a ‘normal distribution curve’
What is a gamete?
It is a sex cell - sperm for males and eggs for females
How many chromosomes does an egg cell have?
23
How many chromosomes does a sperm cell have?
23
How many chromosomes does a zygote have?
46 in 23 pairs
How many chromosomes does an embryo have?
46 in 23 pairs
What does DNA stand for?
Deoxyribose Nucleic Acid
What shape does DNA take?
Coiled double helix (like a twisted ladder)
___________ come as identical homologous pairs (except sex chromosomes)
Chromosomes
How many pairs of chormosomes are there in humans
23, 46 total