7a - 7b Flashcards
Define the term ‘species’ in the biological sense; and the terms reproductive isolation, pre-mating isolating mechanisms and post-mating isolating mechanisms.
Species - a group of populations which evolve independently.
Reproductive isolation - inability to successfully breed outside of the group, this ensures evolutionary independence.
Pre mating isolation - mechanisms which prevent insemination of different species (geographic, behavioural, ecological, mechanical incompatibility, temporal)
Post mating isolation - mechanisms which prevent or minimise the hybrid offspring from spreading their genes. (hybrids infertility, gametic incompatibility, hybrid inviability)
Define species extinction and list the factors that are the common causes of extinction; list human activities that contribute to species extinction.
extinction - when a species is killed completely
Environment, predation and resources, adaptations which have narrow ecological niches
Humans have, destroyed environments, introduced invasive species, hunted species,
Define speciation, briefly describe the conditions leading to allopatric speciation and sympatric speciation, and define adaptive radiation.
Specialisation - process which new species form through isolation and genetic divergence.
Allopatric speciation - when there is a physical barrier that separates the population and the two populations, genes flow divergently.
Sympatric specialisation - when the populations live in the same era however use differing resources
Adaptive radiation - when an event occurs which give a species opportunity to invade a variety of new habitats (dinosaurs extinction allowed mammals to populate)
List the eight major taxonomic ranks of the Linnaean system
Domain, kingdom, phylum, class, order, family, genus, species
define clade and phylogeny.
Clade - a segment of the evolutionary tree
Phylogeny - Modern classification focuses on the evolution of history of an organism. Also known as systematics it utilises evolutionary trees.
List the three domains of living organisms and the types of organisms found in each; define biodiversity; and outline the current view of the phylogeny of eukaryotes.
Archaea - single cells with no nucleus (extremophiles)
Prokara - no nucleus present and are single cellular (virus, bacteria)
Eukarya - membrane bound organelles with nucleus they are often multicellular (arthropods, mammals, plants)
List the differences that distinguish members of the Bacteria from the Archaea
Bacteria - cell wall (peptidoglycan) endospores
Archaea - cell wall (pseudomurein no endospores
Basics structural differentiate as well
Describe the various shapes and relative sizes of prokaryotes
Shapes:bacillus (cylinder) , colli (sphere)and spirillum (spiral)
Size: 0,03 um - 8x6 um the virus are smaller than the bacteria
list the specialisations that have allowed prokaryotes to thrive in a diversity of habitats
Specialisations: flagella , biofilms (polymer matrix to aid surface stickiness) , endospores (protective enclosure that can survive hundred of years) , extreme environment conditions, diverses metabolism, photosynthesis (cyanobacteria) , rapid reproduction, exchange of genetic material (conjugation)
describe digestive endosymbionts, nitrogen fixation, decomposition and bioremediation
Digestive endosymbionts - helps digest cellulose
Nitrogen fixation - rhizobium converts NH4 into amino acids for plants in exchange for food (symbiotic)
Decomposition - Aerobic and anaerobic bacteria reduce accumulation of biological wastes and dead organisms. Nitrifying bacteria release nutrients tied up in dead plant and animal tissue
Bioremediation - degrades contaminants that pose risks, they can eat almost any organic compound
List some beneficial services performed by prokaryotes
Skin microflora, agricultural, food production, medicine, gut microbiome
some adverse impacts of prokaryotes on human activities
Meningitis, STI, ulcers, tetanus, TB, acne, botulism, diphtheria, legionnaire disease
describe how viruses and prions are able to replicate;
Viral replication is done by endocytosis as the cell envelopes the genome of the host cell and disassembles the cells and reassembles it for replication.
list some viruses that cause human disease
Common cold - rhinovirus (droplets, contact)
Flu - influenza virus (droplets, contact)
AIDS - HIV (sexual intercourse)
Encephalitis - MVE flavivirus (tick/mozzies)
Glandular fever / mono - Epstein-Barr (kissing)
Cervical cancer - papillomavirus (sexual contact)
Define virus, bacteriophage, viroid and prion
Virus - protein cell (capsid), often surrounded by an envelope of the host membrane eg: Hendra Virus (HeV) Structure, icosahedral head, tail, baseplate and long fibre tails hold DNA and NRA).
Bacteriophage - Components are DNA, Head, Tail, Fibres (often), Infect bacteria
Viroid - circular RNA molecule,enters the host cell, and forces synthesis of new viroids (Potato spindle tuber viroids)
Prion - consists of an infectious misfolded protein, it causes other proteins to fold in a similar way (eg. mad cow disease).
