Lecture 1: Evolution & Genes Flashcards
‘out of Africa’ hypothesis
about 50,000 years ago homo sapiens started to migrate out of Africa
y-chromosomal adam and mitochondrial eve
the most recent ancestors from which present-day humanity arose
natural selection (darwin)
implies that characteristics may occur more often as a result of a selection procedure consisting of four principles:
- variation
- inheritance
- survival (struggle for existence)
- reproduction rates
pro-creationism
the religiously inspired idea of earth being created by supernatural acts of divine creation (darwin’s ideas go against this)
survival of the fittest
organisms that are not ideally equipped to interact with their environment have a poorer ‘fit’, this limits their chance to survive and reproduce
natural selection
there is no specific plan, the environment plays an important role and evolution is a relatively slow process
selective breeding
a specific, intentional act that produces offspring with particular characteristics that were present in the parental generation
genetic modification
even faster form of selection, where the DNA of an organism is altered. in this way, plants can be made resistant to certain types of toxins so that there is a better chance of harvesting
biogeography
organisms adapt to their specific environments. for example, finches on the Galapagos Islands evolved larger beaks during a drought. this allowed them to survive on the large seeds available
fossil records
sedimentary rock formations allow us to map the time course of evolution. by comparing fossils of skulls to the skulls of their contemporary descendants in their shape and size, it is possible to trace and figure out how and when the organisms evolved
structural similarity
arms, legs, and wings of different species have very similar skeletal structures, which could lead to the conclusion that those species have a shared ancestor
embryology
the different stages an embryo goes through during pregnancy are very similar between different species.
ontogeny recapitulates phylogeny (ernst haeckel)
the essence of the ORP theory is that during embryonic development, every organism goes through all stages of its evolutionary past (embryonic parallelism). human embryo, like fish embryo, go through a stage where they possess gills
molecular biology
modern genetics’ reveals that all organism share common genetic material, supporting the idea of evolution
evolutionary psychology
a branch of psychology that explains behaviors in terms of previous adaptive behaviors in early humans and animals
qualitative traits
often influenced by a single gene and follow a simple pattern of inheritance (such as mendelian inheritance; patterns of inheritance proposed by gregor mendel in which genetic trait is passed from parent to offspring, either dominant/recessive). without the presence of the gene, a person will not posses the trait (all or nothing). usually not affected by environment
quantitative traits
influenced by multiple genes that have only modest contributions, this revolves around the quantity of the presence of certain traits
penetrance
a statistical concept that represents how often the aberrant phenotype (disease/condition) is observed in individuals with the aberrant genotype
allele
one alternative form of a gene, on different chromosomes at the same locus/location
mosaicism
occurs when a person has two or more genetically different sets of cells in their body. if the abnormal cells begin to outweigh the normal calls, it can lead to disease
turner’s syndrome
unusual cell division during early development
polygenetic disorders
enormously complex, this is a disorder with multiple genetic contributions
quantitative trait loci (QTL)
describes how multiple genes at different locations on the chromosomes contribute to the quantitative trait
linkage analysis
geneticists can examine QTLs to look for common events in individuals who have a particular trait or disorder
conspecifics
members of the same species
dichotomous traits
traits that can take on one of two types of traits
phenotype vs genotype
what is observed is called the phenotype and what is genetically transmitted is the genotype
homozygous
each successive generation inherits two alleles/gene variants: one from mother and one from father. if both alleles code for the same trait, they are referred to as homozygous
nucleotide bases
Adenine and Thymine
Cytosine and Guanine
genome
contains all the genetic information of an organism
karyotype (karyogram)
the complete set of chromosomes can be seen as a karyotype often illustrated with a karyogram: all chromosomes in a row. human beings have 46 chromosomes (23 pairs) per cell.
chromatids
during cell division, each chromosome doubles and then temporarily consists of two identical chromatids
centromere
chromatids are attached to the centromere which contains no genetic information
telomeres
repeated genetic sequences at the end of the arms that come off the centromere and the protective reason at the end of a chromosome that safeguards DNA during cell division