Biodiversity and Classification Flashcards
Biodiversity definition
The number of species and the number of individuals of each of the species within any one community.
Genetic diversity definition
number of different alleles of each gene
Species Richness definition
The number of different species in community
Community definition
All the individuals of all the species living together in the same area at the same time
Habitat definition
A place where an organism normally lives within an ecosystem
Niche definition
organisms role in the ecosystem and how it interacts with other species and responds to the environment
Diversity Index
d = N(N-1) / (∑n(n-1)
d – Species diversity index
N – Total number of organisms of all species
n – Total number of organisms of each species
∑ - The sum of
Number in habitat Y
3
5
2
36
4
d = 50(50-1) / 3(3-1)+5(5-1)+(2(2-1)+36(36-1)+4(4-1)
What information is required to calculate an index of diversity for a particular community?
- Number of species;
- Number of individual in each species
Explain why an index of diversity may be a more useful measure of biodiversity.
- Also measures number of individuals in a species
- Some species may be present in low/high numbers;
Give 2 advantages of using an Index of biodiversity rather than an indicator species
- You do not need to identify each species;
- Index takes into account the number of organisms of each of the species.
Ecosystem stability
The more favourable the climate and the more nutrients, shelter, and space available, the greater the range of species, therefore the greater the diversity
Higher diversity ecosystem
more stable ecosystem
This is because, with a wide variety of organisms, it is less likely that a disease or change in climate will affect every organism, allowing the ecosystem to continue to exist
Lower diversity ecosystem
it may consist of only a few organisms, which if they were to die, would severely affect the ecosystem, so we refer to it as unstable.
Suggest one economic argument for maintaining biodiversity.
- medical uses
- commercial products
- tourism
- agriculture
Suggest one ethical argument for maintaining biodiversity.
Prevent extinction
loss of populations
How does farming reduce species diversity?
- Natural plants and animals are lost when the land is cleared, ploughed, etc.
- These activities may reduce VARIETY of food sources and habitats and niches.
- Growth of specific crops / animals occurs and growth of other species is controlled or stopped.
- Pesticides and herbicides may be used to kill unwanted species and fertilisers are designed to encourage growth of specific crops.
A forest was cleared to make more land available for agriculture.
After the forest was cleared the species diversity of insects in the area decreased.
Explain why.
- fewer plant species;
- Fewer habitats
- fewer food sources;
- Aspect of clearing forest (killing insects) eg machinery, pesticides
Farmers clear tropical forest and grow crops instead. Explain how this causes the diversity of insects in the area to decrease.
- few species of plants
- Few sources of food
- Few habitats
- Fewer herbivore so few carnivores;
- Aspect of agriculture (killing insects);
Classification definition
Grouping of organisms
Taxonomy definition
the theory and practice of classification
Species definition
group of similar organisms able to reproduce and produce fertile offspring
Binomial naming system
- name is universal
- first word= Genus name
- second word= species name
- scientific name= underlined
e.g. Homo sapiens or H.sapiens
The Classification system
- 8 levels of taxa and organisms can ONLY belong to one group at each level.
- This creates a Hierarchy – groups are contained within larger groups.
- There is NO OVERLAP – organisms belong in one taxon only, at each level of the hierarchy.
Classification names
Domain (delicious) -Bacteria, Archaea, Eukarya
Kingdom (king)
Phylum (prawn)
Class (curry)
Order (or)
Family (fat)
Genus (greasy)
Species (sausages) - only one type of organism
Explain what is meant by a heirarchy
- Groups within groups;
- No overlap
Bacteria Vs Archaea
Bacteria: are single-celled prokaryotes that have:
* No membrane bound organelles
* Smaller ribosomes (70S) than Eukaryotic cells
* Cell wall made from murein
* circular DNA not associated with histones.
Archaea: are single-celled prokaryotes. Archaea resemble bacteria, however they differ because:
* Genes & protein synthesis mechanisms are more similar to Eukaryotes
* Fatty acids and glycerol molecules are joined by ether bonds rather than ester bonds
* No murein in the cell walls
* More complex RNA polymerase
Explain what is meant by a phylogenetic group
Grouped according to evolutionary links
Phylogenetics
- All organisms evolved from shared common ancestors.
- Organisms, which shared the same common ancestor more recently, are more closely related than those who shared the same common ancestor less recently
Phylogenetic tree
Organisms, which shared the same common ancestor, more recently have branches which are closer together
Courtship behaviour
attract a mate of the right species and right sex, carry out courtship behaviour. It is important to ensure reproductive success
Give two ways in which courtship increases the probability of successful mating
- Attracts same species
- Attracts opposite sex
- Indication of fertility
- Stimulates release of gametes
- Form pair bond
What do modern classification methods use?
- the frequency of measurable or observable characteristics
- the base sequence of DNA
- the base sequence of mRNA
- the amino acid sequence of the proteins encoded by DNA and mRNA.
Why is it difficult to decide which species an organism belongs to OR if it’s a new distinct species?
you can’t always observe their reproductive behaviour or tell if their offspring are fertile because:
1. they are extinct
2. they produce asexually
3. practical or ethical issues
Why did classifying based on observable features lead to mistakes?
some species look similar but have not shared a common ancestor recently
Genetic comparisons
Genetic comparisons are made between different organisms by direct examination of their DNA, mRNA or of the proteins coded for by this DNA. Species are then classified into different groups within the taxonomic hierarchy based on similarities within their genome
DNA comparisons
The more closely related the species the more similar their DNA base sequence will be.
Over time mutations (changes in base sequence) in DNA result in a greater and greater difference in the DNA base sequences of different organisms.
In classification, comparing the base sequence of a gene provides more information than comparing the amino acid sequence for which the gene codes. Explain why.
- longer base sequence than amino acid sequence;
- Introns
- DNA code is degenerate;
Describe how comparisons of biological molecules in two species could be used to find out if they are closely related.
Compare DNA base sequence;
Compare RNA base sequence;
Compare sequence of amino acids
Give two ways doctors could use base sequences to compare different types of HPV.
- Compare DNA base sequence
- Compare mRNA base sequence
- Look for Mutations
Scientists can use protein structure to investigate the evolutionary relationships between different species.
Explain why.
- Amino acid sequences
- Closer the amino acid sequence the closer the relationship
- Protein structure related to triplet sequence
