SL Biology - Topic 5: Evolution and Biodiversity

evolution

evolution

the changes of heritable characteristics of organisms over generations

heritable characteristics

characteristics that can be inherited by the next generation

speciation

the evolution of a new species from an existing one

allele frequencies

the number of times an allele occurs within a gene pool in populations change over time

fossils as evidence of evolution

can be used to tell organisms have changed significantly over time and can be dated and sequenced to show evidence for transitional species

selective breeding as evidence of evolution

showcases the ability to increase expression of characteristics over many generations

variation

differences which exist between organisms of the same species

mutation

source of genetic variation through a change in the DNA base sequence resulting from copying an error during DNA replication and creating a generation of new alleles

crossing over during meiosis

the process by which homologous chromosomes exchange alleles as non-sister chromatids can cross over and get entangled and can result in a new combination of alleles

random orientation

occurs due to the independent arrangement of homologous pairs along the equator of the cell during metaphase

adaptations

characteristics that cause individuals to be well suited to their environment and methods of living

natural selection

the process by which organisms that are better adapted to their environment to survive, reproduce, and pass on their advantageous alleles, to increase in frequency within a population

binomial system

the biological system of naming used to name species according to their taxa

classification structure mnemonic

Do: Domain

Kinky: Kingdom

People: Phylum

Come: Class

Over: Order

For: Family

Great: Genus

Sex: Species

Bryophytes

small terrestrial plants that have no vascular tissue and reproduction takes place via spores, which have rhizoids instead of roots

filicinophytes

ferns which contain vascular tissue as well as roots, stems and leaves which reproduce via spores distributed on the underside of fronds called sporangia

coniferophytes

tall, straight trees commonly known as conifers which reproduce using pollen and ovules

angiospermophytes

flowering plants with roots, stems as well as vascular and cambium tissues who’s flowers produce pollen and contain ovules

porifera

simple aquatic organisms consisting of a colony of cells, commonly known as sponges supported by silica or calcium formations called spicules.

cnidaria

aquatic organisms with a body cavity surrounded by two layers of cells with a single opening for both ingestion and egestion

platyhelminths

flat bodied, unsegmented worms which are short and lack a circulatory system or skeletal structure

annelida

round bodied, segmented worms with a ring-shaped body with a separate mouth and anus

mollusca

a diverse group of animals including snails, slugs, mussels and limpets with a muscular foot and separate openings for mouth and anus

arthropoda

animals with segmented bodies, a hard exoskeleton and usually one pair of jointed limbs per body segment

chordata

all vertebrates, having a notochord, a hollow nerve chord, a series of pharyngeal slits and a tail which extends beyond the anus

clade

a group of organisms that have all descended from a common ancestor

homologous traits

characteristics which may differ in form and function in species but that have a shared evolutionary origin

analogous traits

characteristics with the same function but which do not share an evolutionary origin