Chapter 2 Flashcards
Natural selection
the most critical mechanism for evolutionary change; described by charles darwin
fixity of species
the notion that species, once created, can never change
cell
smallest unit that can be considered to be alive
DNA
Deoxyribonucleic acid
Somatic cells
make up structures of body
gametes
sex cells that make spermatoza and ova
Zygote
The single cell that is formed when an egg and sperm cell unite
What are Chromosomes
humans have 46 chromosomes
arranged in 23 pairs
22 autosome and one pair of sex chromosomes x and y
Define chromosome
bodies found in the nucleus that contains genetic material
Chromatid
Strands of replicated chromosome
karyotype
classification and arrangement of photographed chromosomes
Locus
physical location on a chromosome where a gene is found
Homologous Chromosomes
chromosomes with corresponding loci. They share the same genes but no necessarily the same alleles.
Mitosis
Normal cell division. Most form of cell division
Meiosis
the form of cell division that produces gametes
Evolution
a change of gene frequency OF A POPULATION over time
Gene
A sequence of DNA that codes for a specific product (protein)
nucleotide
building blocks of DNA molecule