Classification + Biodiversity Flashcards
Biodiversity:-
A measure of the number of different species and the number of individuals in each species in a given environment.
Species:-
A group of organisms with a large number of common characteristics and could be interbred to produce fertile offspring
Spacial biodiversity variation:-
Biodiversity generally increases moving towards the equator with the greatest biodiversity found in the tropics. Tropical rain forests and coral reefs = most diverse habitats in world.
Biodiversity variation over time:-
Can increase or decrease due to:-
Sucession
Natural selection
Human influence
Sucession(3):-
- Over time a community of organisms changes its habitat, making it more suitable for other species.
- This change in composition of a community over time is called succession.
- It increases animal biodiversity but ultimately decreases plant biodiversity.
Human influence on ocean biodiversity:-
Over fishing has depleted fish stocks.
Human influence on tropical rainforest biodiversity:-
Deforestation for farming, roads and industry has destroyed habitats.
Human land misuse influence on biodiversity:-
Trampling by cattle w/ increased temp due to climate change has increased area of deserts.
Human pollution influence on biodiversity:-
Rivers poluted with industrial chemicals e.g. Yangtze River Dolphin extinct in 2006.
Significance of biodiversity:-
- A small number of plant species provide staple foods e.g. wheat and rice.
- Living organisms provide important raw materials e.g. rubber/cotton.
- medicinal drugs are derived from plants and fungi e.g. digoxin for heart disease comes from digitalis (foxglove).
- As biodiversity decreases, we lose potential undiscovered resources.
3 levels of assessing biodiversity:-
Habitat level- counting no. of individuals and species.
Genetic level-examining genes.
Molecular level- examining DNA and proteins.
Genetic level assessing:-
Examining all the alleles in the gene pool of a population rather than individuals
Gene pool:1
All the different alleles of all the diff genes in a population. No of different alleles in pool of species = genetic diversity.
Gene locus:-
A gene’s position on a chromosome
Polymorphic genes:-
More than 1 allele at the same locus.
Polymorphism:-
The occurrence of more than 1 phenotype in a population that cannot be caused by mutations.
Sampling techniques:-
Quadrats
Transects
Sweep nets
Kick sampling in a stream.
Simpson’s diversity index:-
Gives value between 0 and 1. Higher value= higher biodiversity.
Molecular level assessing:-
Done using DNA sample fingerprinting and sequencing. Sometimes base sequence mutations occur, giving rise to non-coding sequences that give a unique DNA fingerprint. Can accumulate across generations, giving rise to a quite different DNA profile. Comparing these in different organisms shows how closely related they are. Greater difference= greater biodiversity.
DNA fingerprint/profile:-
Terms for a pattern unique for each individual, related to the base sequence of their DNA.
Natural selection:-
The gradual process in which inherited characteristics become more or less common in a population, in response to the environment determining the breeding success of individuals possessing those characteristics.
Theorised as reason for evolution by Darwin in 1859.
Natural selection stages(6):-
Mario Very Cleanly Sprints Really Pacily
Mutation. Variation. Competitive advantage. Survival of the fittest. Reproduction. Pass advantageous alleles onto offspring.
Adaptation:-
The changes in species, as a useful characteristic becomes more common.
Specific characteristic = adaptive trait.
Adaptation types:-
Anatomical
Physiological
Behavioural
Classification:-
The arrangement of organisms into discrete and hierarchical groups with other closely related species.
Taxonomy:1
The branch of biology concerned with naming and classifying organisms.
Phylogenetic tree:-
Shows evolutionary history of diff species and indicates common ancestors and lines of descent. Closer branches= more recent point of divergence from common ancestor and therefore, the closer the evolutionary relationships.
Linnaean taxonomy:-
Basis of system used today. Made by Carl Linnaeus. Uses hierachy approach and a binomial system.
Order for hierachical classification (use Dominic King Palethorpe Chokes On Families’ Gay Spunk)
Domain Kingdom Phylum Class Order Family Genus Species
Hierarchical system exta info:-
Each feoup has unique features (discrete, no overlap). Organisms more closely related going down group.
Binomial system:-
Capitalised gemus followed by lower case species. Written in italics or underlined.
3 advs of binomial system:-
Unambiguous naming.
Based in Latin so avoids confusion of local common names and different languages.
Shows relation by sharing parts of names.
Tentative nature of classification systems:-
Based on current knowledge so it may alter as new evidence emerges leading to organisms changing groups.
Need for classification system (4):-
- if a new animal is discovered, we can predict some of its other characteristics.
- easier to identity organism by a name.
- conservationists find it more useful to count families than species when describing changes in an ecosystem.
- phylogenetic system allows us to infer evolutionary relationships by putting them in the same taxon.
Taxon:-
A group within this classification hierachy and is a collection of organisms sharing basic features.
3 domains:-
Bacteria(eubacteria):- often called true bacteria.
Archaea(archaeabacteria):extremophile bacteria.
Eukaryota.
3 DOMAIN THEORY.
5 kingdoms:- (use FAPPP)
Fungi Animalia Plantae Protoctista Prokaryotae
Prokaryotae:-
All bacteria.
All unicellular, no membrane bound organelles.
Murein cell wall
Protoctista:-
May have characteristics of animal or plant cells or both. Mostly unicell but can be multi(seaweed or algae). Membrane bound organelles.
Plantae:-
Plants
Fungi:-
Can be uni (yeast) or multi (mushroom). Chitin cell walls.
Animalia
Animals
Classes:-
Fish Amphibians Reptiles Birds Mammals
Homologous structures:-
Structures that all share a common form. Used w/molecular data to construct phylogenetic trees. Derived from common ancestor, structurally the same but may be adapted to a diff function.
Homologous structure example:-
Pentadactyl limb (5 digits) found in mammals, birds reptiles and amphibians. E.g. Human arm and bird wing structurally the same but have adaptation to a different function.
Divergent evolution:-
When a common ancestral structure evolves to perform different functions.
Analogous structures:-
Have the same function but don’t share the same structure and aren’t derived from a common ancestor.
Convergent evolution:-
The tendency of unrelated organisms to acquire similar physical structures (in response to their environment).
Species:-
A group of organisms with similar physical characteristics that can interbreed to produce fertile offspring.
Gel electrophoresis:-
DNA fragments or proteins are displayed as bands on an electrophoresis gel. DNA SEQUENCING. Can reduce mistakes made in classification due to convergent evolution.
