IB biology SL - A3.1

A3.1 - diversity of organisms

5 kingdoms

Plantae, Fungi, Animalia, Bacteria, Archarea

Organism

living entity

A singular cell is an organism

True, but only in unicellular organisms, otherwise only the full creature is an organism

population

a group of organisms from the same species

community

two or more species sharing the same area (even micro-organisms or plants count towards this)

Variation

the differences between members of a group

Continuous variation

variation that can be expressed in an infinite number of variables. ex. Height. (displayed on a histogram using ranges)

Discrete variation

variation that can be expressed in a countable number of variables. ex. eye colour. (displayed on a bar graph)

intraspecies variation

variation that inheritable and transmittable from parent to offspring

mutation

the changes in gene sequence in DNA

Gene flow

the movement of genes between different groups of organisms

Meiosis

2 parents combining their genes to give the offspring a random mix of both of their genes

3 Domains

Archarea, bacteria, eukarya

Heirarchy of organism specification

Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species

Morphology

sorting organisms on clearly distinguishable shapes and forms

Limitation of morphology

Might look the same but be totally different species. ex. Turtle vs tortoise

Binomial nomenclature

A system of naming and distinguishing between organisms

The same _____ can reproduce but the offspring would be infertile

Genus

Rules of binomial nomenclature

Genus begins with a capital letter, species are all lowercase. If handwritten, the name should be underlined. If typed, the name should be Italicized. If the species has been referred to previously you can shorten the genus to just the capital letter.

Values of using binomial nomenclature

• see how closely related a species are

• universal communication among scientists

• ultra-specific and precise

Prokaryote chromosomes

• circular DNA molecule

• Naked (no associated protiens)

• plasmids are OFTEN present (used to control genes)

• only one chromosome

Eukaryote chromosomes

• Linear DNA molecule

• associated with histone molecules

• no plasmids present

• 2 or more different chromosomes

How are human genomes sorted?

Size

How many genome PAIRS do humans have?

23 pairs (46 total)

how many PAIRS of sex chromosomes to humans have

1 pair, either XX or XY

what decides the length of a genome

Base pairs

Diplod vs Haploid chromosomes

Haploids only have ONE copy. ex. sex chromosomes. While diploids have 2 copies. ex every other chromosome

homolouge

a chromosome that’s a member of a homologous pair

tetrad

a strucutre of homologous chromosomes

Karyotypes

The way chromosomes are numbered

whole genome sequencing (WGS)

a way of analyzing a whole whole genome. They analyse short part s of it and then piece it together later

Value of whole genome sequencing

Allows researchers to identify genetic disorders

informing lifestyle choices. ex. Diet

Limitations of whole genome sequencing

high cost

slow

speciation

a process where an existing species splits into 2 and breeds separately for generations until they can no longer create fertile offspring together, creating a new species

possible reasons for speciation

physical barrier. ex. river

different mating cycles