Classification Processes Flashcards
Recognise that biological classification can be hierarchical and based on different levels of similarity of physical features, methods of reproduction, and molecular sequences.
Several systems of biological classification exist, including Linnaean classification, reproductive classification, and cladistics or molecular classification
Describe the classification system for:
- similarity of physical features (the Linnaean system)
- methods of reproduction (asexual, sexual - K and r selection)
- molecular sequences (molecular phylogeny - also called cladistics)
- Linnaean classification uses hierarchical taxa to classify organisms according to their physical structures.
- Classification based on reproductive characteristics uses asexual, sexual reproduction, and K or r strategists to classify organisms
- Cladistics uses molecular sequencing to organise organisms into clades based on their evolutionary relatedness.
Define the term clade
- A group of organisms that is believed to comprise a common ancestor and all of its evolutionary descendants.
recall that common assumptions of cladistics include a common ancestry, bifurcation, and physical change
Cladistics classifies organisms by grouping them according to their evolutionary relatedness through common ancestors. Groups of organisms are separated into clades through analysis of their shared characteristics and derived characteristics. This allows for the formation of a cladogram.
interpret cladograms to infer the evolutionary relatedness between groups of organisms
analyse data from molecular sequences to infer species’ evolutionary relatedness
Populations of specices that become separated accumulate differences in their DNA sequence over generations. Mutations occuring in their gametes (sex cells) change the sequence of nucleotides and, as more time passes, greater differences are seen between the two diverging species. Eventually, the two populations will have such great differences in their genome that reproduction will no longer be possible and they become two different species. This point of diversion is referred to as bifurcation and is evident on a cladogram where one species diverhes into two. comparing the number of similarities and differences in species that share a common ancestor is one way scientists can determine evolutionary relatedness and how much time has passed since they diverged from their common ancestor.
recognise the need for multiple definitions of species
understand the ecosystem are composed of varied habitats (microhabitat to ecoregion)
interpret data to classify and name an ecosystem
Explain how the process of classifying ecosystems is an important step towards effective ecosystem management (consider old-growth forests, productive soils and coral reefs)
Classification of ecosystems is important ar a planning level when making decisions about management and conservation of natural areas. Since ecosystems are dynamic, complex structures, accurate classification can be challenging. scientist use the following for main classification systems for this important work:
1. Holdridge life zone classification scheme
2. specht classification system
3. ANAE classification system
4. EUNIS habitat classification system
Describe the process of stratified sampling in terms of:
- Purpose (estimating population, density, distribution, environmental gradients and profiles, zonation, stratification)
- Site selection
- choice of ecological surveying technique (quadrats, transects)
- minimising bias (size and number of samples, random-number generators, counting criteria, calibrating equipment, and noting associated precision)
- methods of data presentation and analysis
Stratrifed sampling is a process used in ecological studies to divide an area into smaller sections or categories to improve the accuracy and usefulness of data collected
