Studied by 20 peopleselective breeding
the process by which humans can select or remove particular traits from a population by directly controlling the breeding of animals or plants.
artificial selection
another term for selective breeding
desirable trait
the preferred characteristics that scientists selectively breed for
recessive allele
an allele that can be masked by a dominant allele, is only shown in the presence of another recessive allele.
homozygous
the presence of two identical alleles/genes
antimicrobial agent
any agent that kills or stops/slows microorganisms from reproducing
anitmicrobial resistance
when pathogens evolve, causing medicines to no longer be effective against them
bacterial conjugation
the direct transfer of genetic material between cells
normal flora
types of bacteria that are permanent inhibitors of different body sites in a healthy person.
antigenic drift
small and gradual changes to the genes encoding for viral surface antigens
antigenic shift
sudden and significant changes in the genes encoding for viral surface antigens
viral recombination
the combination of surface antigens from two or more different strains of a virus to form a completely new virus subtype
the fossil record
the information derived from fossils arranged in chronological order
Cambrian explosion
a period of rapid diversification of multicellular life (535 mya)
extinction
the dying out of a species on a global or regional level
fossilisation
the process by which an organism becomes a fossil
sediment
naturally occurring solid material that is broken down into fine pieces and settles
sedimentary rock
a rock that has formed through sediment being hardened by pressure
permineralised fossil
fossil formed when groundwater deposits minerals into organic material, creating a mineral relic
mould fossil
a fossil formed when a living thing decomposes underneath sediment, creating a cavity in the shape of the dead organism
cast fossil
a fossil formed when a mould fossil is filled with sediment
trace fossil
an indication of the presence of an organism, rather than the organism itself.
relative dating
a dating technique used to determine the relative age of a fossil by comparing its position to other fossils or rock in the surrounding rock strata
absolute dating
a dating technique used to determine a fossils age by measuring the relative amounts of radioisotopes to their products.
fossil succession
the principle that fossils of the same age will be in the same strata, and the fossils found above will be younger and below will be older.
relative age
the age of a fossil, determined by relative dating
stratum/strata
a layer of sedimentary rock
index fossil
a fossil that comes from an organism that was geographically widespread, and existed for a short but precisely known period of time.
transitional fossil
a fossil that shows traits that are common in both an ancestral group and its descendent group. this helps chart evolutionary changes in species/groups.
absolute age
an estimate of the age of a fossil or rock
radioactive isotope
a radioactive atom of a specific element. this atom breaks down into a stable and predictable product.
half-life
the time taken for half the mass of a radioisotope to break down into its products.
dating period
the range of time since fossilisation in which a particular radioisotope series can be used before it breaks down into its product
radiocarbon dating
a form of absolute dating used to determine the age of a fossil by measuring the properties of radiocarbon, a radioactive isotope of carbon.
structural morphology
the study of physical structures to establish relatedness
homologous structures
features founds in different species that may look and function differently but can be shown to have derived from a common ancestor
divergent evolution
the process in which a common ancestor evolves into two or more separate species
analogous structures
structures that serve similar biological functions but are not derived from a common ancestor
convergent evolution
the process in which distantly related species evolve similar traits overtime due to similar selection pressures
vestigial structure
features that have lost most or all of their usefulness as a result of evolution
molecular homology
the study of similarities in the nucleotide sequences of DNA or amino acid sequences in proteins between organisms to establish relatedness
conserved genes
genes that have remained largely unchanged throughout evolution, and are found across the genomes of many different species
haemoglobin
a protein found in red blood cells that is responsible for transport of oxygen throughout the body
cytochrome C
an enzyme found in the mitochondria that plays a role in respiration reactions
mitochondrial DNA
circular DNA found within mitochondria
genome
the complete set of DNA housed within an organism
phylogenetic tree
a diagram used to show the relatedness between organisms
phylogenetics
the study of relatedness between organisms
evolutionary relationship
the relatedness of organisms based on shared ancestry
lineage
a direct sequence of species that evolved from a common ancestor
root
a line at the origin representing the earliest common ancestor
branch
each line on the phylogenetic tree
node
the point where the branches split from each other, representing a divergence between those two taxa
leaf
at the end of a branch representing where the present day or extinct species are found
adaptive radiation
the rapid divergent evolution of a species, thereby producing a wide array of species/forms
homo sapiens
the species name for modern humans
mammals
warm blooded vertebrates belonging to the taxonomic class Mammalia, that have mammary glands, hair/fur, three middle ear bones and one lower jaw
primates
the highest order of mammals that have opposable digits and binocular vision
hominoids
members of the superfamily Hominoidea that includes apes and humans
hominins
members of the taxonomic tribe Hominini that includes modern humans and out upright walking ancestors
Cranium
the part of the skull that covers the brain
prehensile
the ability to grasp objects
opposable digit
a digit that is able to touch all the other digits
precision grip
a type of grip involving the tips of the thumb and finger, used by primates for precise manipulation of objects of various sizes
power grip
a type of grip involving the palm and fingers used by primates for moving and manipulating objects.
bipedalism
using two legs for walking upright
canine teeth
a type of tooth in mammals that is relatively long and pointed
foramen magnum
the hole in the base of the skull through which the spinal cord passes. a more centralised one indicates bipedalism.
brow ridge
a bony ridge above the eye sockets
sagittal crest
a ridge of hard bone running lengthwise along the top of the skull. a more pronounced one indicates strong jaw muscles.
femur angle
the angle between the top and the bottom femur while standing. it is greater for hominins when compared to other primates.
genus
a taxonomic rank above species and below family. Modern humans belong to the genus homo.
biped
an individual that moves on two legs
arboreal
living in or amongst trees
cerebrum
the largest part of the brain
Gene pool
All the genes found within a population/ the complete set of alleles
Gene
Section of DNA that codes for a particular protein/ characteristic
Allele
Different versions of a gene
Population
group of individuals of the same species living in the same location
Allele frequency
Number of each version of a gene in a population. It can be impacted by factors such as environmental factors, natural selection, predators and disease/ mutations
Genotype
The genetic composition of an organism at a particular gene locus
Phenotype
The physical characteristics of an organism that are the result of gene expression and the environment
Genetic diversity
Variation in genetic makeup/ alleles in a population
Mutation
A permanent change to a DNA sequence which can occur spontaneously or induced by a mutagen
Mutagen
An agent that causes mutations in DNA
Deleterious
Alleles that have an overall negative effect on individual fitness when expressed
Heritability
Transmission from parent to offspring
Germline Cell
A cell involved in the generation of gametes in eukaryotes
Somatic cell
any cell in an organism that is not a germline cell
Point mutation
Changes to a single nucleotide in a DNA sequence
Silent mutation
A mutation in which a nucleotide is substituted for another, changing the codon, but still coding for the same amino acid. Therefore, there is no effect on protein structure
Missense
A mutation in which a nucleotide is substituted for another, changing the codon and coding for a different amino acid. Therefore, there can potentially
Nonsense
A mutation in which a nucleotide is substituted for another, changing the codon to a stop codon, prematurely ceasing translation of the gene’s mRNA. Therefore, there is an effect on protein structure
Frameshift
A mutation that involves the insertion or deletion of one or two nucleotides, altering every codon from that point forward
Degenerate
A a property of the genetic code which means that a single amino acid can be coded for by more than one amino acid
Aneuploidy
When a cell or organism varies in the usual amount of chromosomes in its genome by the addition or loss of a chromosome
Polyploidy
When an organism contains additional sets of chromosomes in its genome
Environmental selection pressur
a factor in the environment that impacts an organism’s ability to survive and reproduce. e.g. limited resources, predation, competition
Competition
interactions between organisms in which both are negatively impacted when vying for the same limited resource. Can exist within or between species
Natural selection
a mechanism through which organisms that are better adapted to an environment have an increased chance of surviving and reproducing, passing on their alleles
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