Biodiversity (2.1)
Classification
Evidence for relatedness
Factors affecting
Organisation of every living thing into groups
Hierarchial
Every living organism is sorted into one of 5 kingdoms
Phylum
Classes
Orders
Families
Genus
Species
It has a tentative nature
It is always changing as new information / research is released
3 Domains
Eubacteria
Archea
Eukarya
Eukaryotic
True bacteria
Prokaryotic + Extremophiles
Extremophiles live in harsh environmental conditions
Halophiles - lives in areas of high salinity
Animalia
from rRNA
Multicellular eukaryotic organisms
Cells do not have cell walls
Heterotrophic, holozoic nutrition - digest food internally
Plantae
Multicellular eukaryotic organisms
Fungi
Cellulose cell walls
Autotrophs - Uses sunlight for energy to make organic molecules via photosynthesis
Multicellular / Unicellular, Eukaryotic
Chitin cell walls
Saprotrophic - Secrets enzymes extracellularly on food
Reproduces via spores
Multicellular grow in long threads (Hyphae, lots together are a mycelium)
Protoctistia
Unicellular Eukaryotic organisms
Heterotrophic / Autotrophic / Both
Very diverse
No Chlorophyll, cell wall + complex structure with nucleus
Complex cell structure + nucleus
Complex cell structure + nucleus
Prokaryotae
Unicellular
Complex cell structure + nucleus
Simple cell structure + No nucleus
No membrane-bound organelles
70S ribosomes
Peptidoglycan (murein) cell wall
Heterotrophic / Autotrophic
Species
Two organisms that can interbreed and produce fertile offspring
Smallest taxonomic group
Phylogenetic trees
A diagram which represents evolutionary pathways leading to different species, each branch represents time
Divergent evolution
More closer the branch = more related the organisms
Convergent Evolution
Homologous structures
Similar look, different function
Pentadactyl limbs
Common ancestor, common structure evolved for different functions
Analogous structures
Similar look and function, but different origins
Common structure and function evolved from different animal groups
Gel electrophoresis (DNA Fingerprinting)
Compare DNA sequencing (Bands are produced
Similar bases = closely related
Gel allows small fragments to move further and the electrical charge causes movement of negatively changed DNA to positive electrode, banding pattern is produced. (Description, not needed)
Sexual dismorphism
Males + Females look different or similar
Amino acid sequencing
Must be named gel electrophoresis in exam
Amino acid sequencing of a protein is compared
Morphology
Looking at the shape and form of an organism, evidence used in the past before information was found
DNA hybridisation
More similar = closely related
DNA is taken from two species
Cut and mixed and reforms
If closely related, lots of bonds should form
If you want to break the new strands, a higher temperature would be required depending on how closely related they are.
Immune response
- Human blood injected into a rabbit
- Rabbit blood is removed
Rabbit is the intermediary
- It is added to other samples (Animal)
- Antibodies and antigens clump leading to precipitate forming, and the solution turning cloudy
Anatomical comparisons
Compare skeletons
Backed up with DNA
Richness - Number of species
Evenness - Number of individuals in those species
Biodiversity increases from poles to the equator
UV light causes higher rate of mutation - more rapid evolution
More species types = more habitats and food types
More stable temperature range and water availability = good conditions for survival
More species + individuals = more competitions leading to more specialized and narrower exploitation of food types making it more difficult to move out
Climate change has sped up extinction rates leading to rapid expansion and diversification of species
Practical
To investigate biodiversity, evenness and richness must be accounted for
A quadrat could be used, if sampling in a field.
A net and boots would be used for kick sampling
Random sampling to remove bias
Increases reliability
Risk assessment
Biting and stinging insects and stinging or thorny plants
Ecosystem hazards
Risk of scratches and allergic reactions
Reduce risk by wearing insect repellent and protective clothing
Tide on a seashore
Slippery surfaces
Causes risk of strains and sprains
Appropriate footwear with grip should be worn
Simpsons biodiversity index
Succession
Habitat
Human
Light intensity
Succession
Space
Natural selection
Farming
Over-Farming
Misuse of land
Pollution
Order in which species appear over time
First species appear, makes changes to the environment, passes to the second and repeats
Natural selection
Genetic biodiversity
Genetic polymorphism
Can be assessed by determining the number of alleles at one gene locus
Polymorphism - A species has different forms
Assessed by determining the number of alleles (Different forms of genes) at different loci, within a given species
More genetic variation = more biodiverse
Mutation in the population causes variance
Those with variation have an selective advantage, allowing them to easily survive a selection pressure
Selection pressure - Something causes the death of an organism (Predation, disease, climate)
Individuals which survive pass on their alleles to the offspring, which are then passed down to many generations
Adaptations
Anatomical
Physiological
Behavioural
Example: Fennec fox (Lives in the desert)
Small
Large ears = high s.a to vol. ratio to lose heat
Breathing is faster when temperatures are high to lose heat
Fur = camoflauge
Crepuscular - active at dawn + dusk, when temperatures are cooler
Digging dens to shelter during day