BY2 - Classification and biodiversity

It reflects evolutionary relatedness.

Closely related organisms are grouped together.

Organisms in the same group have a more recent common ansestor with eachother than with organisms not in their group.

A hierarchy is a system in which smaller groups are components of larger groups.

Each grouping in the system is a taxon. Bigger taxa contain smaller taxa. Within each taxon, organisms are more similar to each other, and more closely related to the organisms outside the taxon.

Hierachy of classification is domain, kingdom, phylum, class, order, family, genus, species.

A domain is the largest taxon, all living things belong in one of three domains.

1) Eubacteria: familiar bacteria such as E.coli. They are prokaryotes.

2) Archaea: bacteria that often has unusual metabolism. Live in marginal habitats and are also prokaryotes.

3) Eukaryota: plantae, animila, fungi and protoctista. 

Organisms in different kingdoms have major significant differences. 

Prokaryota consist of Eubacteria and Archaea

Protoctista, Fungi, Plantae and Anamalia consist of Eukaryota

Microscopic. Contains all bactera and cyanobactera

They are prokaryotic

Single-celle

No nucleus

Mesosome in some

Photosynthesis lamellae in some

70S ribosomes

No ER

No vacuole

Peptidoglycan cell wall

Saprotropih parasitic  or autrotrophic

Eukaryotic

Single-celled or multicullar

Have a nucleus

Have mitochondria

Some have chloroplasts

80S Ribosomes

Have ER

Some have a vacuole

Some have cellulose cell wall, some have no cell wall

Some autotrophic, some heterotrophic

No nervous coordination 

Eukaryotic

Multicellular

Have a nucleus

Have mitochondria

Have chlrooplasts

80S ribosomes

Have ER

Have a large, central, permannet vacuole

Cell wall made of cellulose

Autotrophic

No nervous coordination

Eukaryotic

Single-celled or hyphal

Have a nucleus

Have mitochondria

No chloroplasts

80S ribosomes

Large, central, permanent vacuole

Cell wall made of chitin

Saprotrophic or parasitic

No nervous coordination

Eukaryotic

Multicellular

Have a nucleus

Have mitochondria

No chloroplasts

80S ribosomes

Have ER

Small, scattered, temporary vacuole

No cell wall

Heterotrophic

Nervous coordination

Divergent evolution is where a common ancestral structure has evolved and performs different functions.

Convergent evolution is where structures evolve similar properties but have different development origins.

DNA sequences: more closely related species show more similarity in their DNA base sequences 

DNA hybridisation: DNA from two species is extracted, separated and cut into fragments which are then mixed, complementary base sequences then hybridise together. 

Amino acid sequences: more similar the amino acid sequence of the same protein in two species, the more closely related they are

Immunology: mix the antigens of one species, with specific antibodies of another, they make a precipitate. Closer relationship, more precipitate

Morphological definitions is where if two organisms look very similar, likely to be same species. Sexual dimorphism may be taken into account.

Reproductive definition: two organisms are in the same species if they can interbreed to produce fertile offspring.

Each oranism has two names, genus and species

Genus is the first word, capital letter

Species is second, doesn't have a capital letter

First time the scientific name is used, it is written in full

If used again, genus may be abbreviated 

Both names are printed in italics, or underlined when hand-written

Number of species/species richness

The number of organisms within each species

More plants grow at high light intensity than low light intensity, bright environment supports more hebivores and carnivores than a dull one

More enregy flowing through an ecosystem produces more species and more indiviudals, equatorial regions have much higher biodiversity than polar regions

1) Succession - over time, a community of organisms changing its habitat to make it more suitable for other species. The change in composition of a community over time.

2) Natural selection

3) Human influence 

1) Mutuation: differences in DNA

2) Variation: different physical appearence/behaviour

3) Competitive advantage: some more suited to environment and out-compete others for resources

4) Survivial of the fittest: those more suited survive better

5) Reproduction: those more suited have more offspring

6) Pass advantageous alleles to offspring: offsprong inheret advantageous alleles, they are also more suited