Biology U4 AOS2 MEGA LIST

Margie and Cassie's biology mega list

selective 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