Inheritance & Evolution Flashcards
Species
A group of organisms that can interbreed to produce fertile offspring.
Liger
Hybrid made when a tiger and lion mate. Ligers are unable to produce offspring (infertile).
Hybrids
The infertile offspring of two different species.
Variation
The way in which living things are different from each other.
Types of Variation
Genetic Variation
Environmental Variation
Genetic Variation
Variation passed on through genes in the family.
Environmental Variation
Variation caused by the area/environment a living thing is surrounded by.
Why are wolves and dogs different
species?
Because if they bred together they
produce infertile offspring.
DNA
A double helix structure containing all of your genetic information, found in the nucleus and stored in chromosomes.
Chromosomes
Structures made of tightly wound DNA.
How many pairs of chromosomes do humans have?
23
Genes
Genes are sections of DNA that code for specific proteins / characteristics
Allele
Variation for each gene.
Dominant Allele
A ‘strong’ trait – will always be expressed if present.
Recessive Allele
A ‘weak’ trait – only expressed if both alleles are recessive / no dominant allele.
Cell was first discovered by:
Robert Hooke (1665)
Who bred pea plants to understand characteristics are inherited?
Gregor Mendel (1856-1863)
Who made the word ‘gene’ by experimenting with fruit flies?
Thomas Morgan Hunt (1910)
Who worked out the structure of DNA
Franklin, Crick and Watson (1950)
How does natural selection happen?
Overproduction
Genetic Variation
Selection
Adaptation
Overproduction:
Most species produce more offspring than can survive to maturity
Selection
The genes that cause individuals to be better at surviving and reproducing are selected for because those individuals pass their genes down instead of dying.
Evolution
The concept that over time organisms become more adapted to their environment by the process of natural selection.
Common Descent
The concept that all life on earth including humans evolved from the same ancestor.