B5.2 Flashcards
(36 cards)
What is evolution?
The gradual change in a species over time
What is natural selection
The idea that the fittest will survive and pass along their traits to their offspring.
What are fossils?
The preserved remains or traces of an organism that lived in the past.
What is classification?
A system that groups organisms using observable characteristics
What are the five kingdoms?
Plants, Animalia, Fungi, Prokaryotes, Protoctista,
Unique characteristic of animalia
They are heterotrophs
Unique characteristics of plants
They are autotrophs
Unique characteristics of prokaryotes
They have free DNA
Unique characteristics of fungi
They are Saprophytic
Unique characteristics of Protoctists
They can easily switch between aerobic and anaerobic respiration
Why aren’t viruses classified into a kingdom
Because they cannot reproduce by themselves and have to infect the DNA of a cell and wait for that cell to reproduce in order to spread
Why is it hard to characterise a hybrid animal?
Because they display the phenotype of two different animals
What is variation?
Differences between a species
What are the two types of variation?
Genetic and Environmental
What is a dominant allele?
An allele which only needs one copy of the gene present to be expressed
What is a recessive allele
An allele that needs two copies of itself to be expressed
What can happen if a mutation occurs in the DNA base before the gene?
The gene may not be transcribed
What can happen if a mutation occurs within a gene?
The gene will code for a different amino acid and the enzymes produced will not function properly.
How can a mutation influence phenotypes?
If a mutation occurs within a gene, the DNA bases may be changed, added or deleted.
This changes the sequence of the bases which means the order of the bases produced in mRNA during transcription may be different.
This will form different amino acids.
If the protein is an enzyme, it’s active site may change shape which means it will not be able to bond to its substrate and catalyse a specific chemical reaction.
What is genetic variation?
A variation that is caused by genes inherited from your parents. E.g. genes can code for more melanin to be produce and can also cause people to be born with weaker eyesight
What is environmental variation?
Variation which is caused by the environmental conditions e.g. the sun can cause darker skin and UV retinal damage
What is a clone?
A clone is an identical copy/exact replica
What is sexual reproduction?
Reproduction that involves two different parents (a male and a female)
What is asexual reproduction?
Reproduction that only involves one parent
