B5. Genes, inheritance and selection Flashcards
What is a phenotype?
The appearance of an organism
What is variation?
Differences within species
What are the two types of causes of variation?
Environmental
Genetic
What is genetic variation?
The genetic material you inherit
What is environmental variation?
The environment you live in
What is discontinuous variation?
characteristics which fall into distinct groups
What is continuous variation?
Characteristics which can be any value between a minimum and a maximum
Is discontinuous variation caused by both genetic and environmental
No, only genetic
Is continuous variation caused by both genetic and environmental
Yes
Give two examples of continuous and discontinuous
Contin - Height, Leaf surface area, skin colour
Discon - Gender, eye colour
What are diploid cells?
Normal body cells
What are gametes?
Sex cells, sperm and ova
What are haploid cells?
Contain half the genetic material of a normal cell
When two haploid gametes join together, they form a diploid cell called a?
Zygote
What is a genome?
The organisms entire genetic material
How are gametes made?
Meiosis
How does meiosis work?
It produces 4 haploid cells. ovaries produce ova and testes produce sperm
What happens in the second stage of meiosis? ( first stage is the same as mitosis
Chromosomes line up along middle of both cells
Chromosome is pulled in half to opposite ends. Resulting in four haploid cells
What is the genotype?
The alleles you have
What is an Allele?
Different forms of a gene
What are the 5 phases of mitosis?
Interphase
Prophase
Metaphase
Anaphase
Telophase
What is homozygous?
Two copies of the same allele
What is hetrozygous?
different alleles
What is the difference between mitosis and meiosis?
Mitosis - 2 identical daughter cells
Meiosis - 4 haploid cells
What is a mutation?
Sequence of DNA bases are altered
What is sickle cell anaemia?
Causes red blood cells to form sickle shape which makes them smaller. This stops oxygen and blood reaching areas of the body because of blood clots
What is cystic fibrosis?
Sticky mucus is released into trachea, bronchi and alveoli
What is evolution?
Gradual change over time in a species
How do organisms evolve?
Through natural selection. Genetic variation and mutations
What is survival of the fittest?
Genetic variation causes a range of phenotypes so those organisms best suited to their environment will survive and reproduce passing on advantages characteristics to off spring. Less adapted die . This is repeated over a very long period of time
What is a fossil?
Fossils are formed when animal and plant remains are preserved in rocks
What is classification?
Sorting living organisms into groups
Why do scientists classify organisms?
To identify species
Predict characteristics
Find or show evolutionary links
