U3 T1 - Describing Biodiversity Flashcards
Classification of an organism can be based on?
Similarity of physical features
Methods of reproduction
Molecular sequences
Species definition
group of organisms that can potentially interbreed, or mate, with one another to produce viable, fertile offspring.
example of an interspecfic Hybrid
Mule made from a donkey and a horse
Describe the Linnean classification system
Kingdom,Phylum,Class, Order, Family, Genus, Species
Describe the methods of reproduction classification system
reproduce either Asexually (1 parent with no variation) or sexually (2 parents with variation)
r- Strategiests- short life span- high rate of reproduction, quick to mature
K- strategists- low offspring, higher gestation period, higher survival rate
describe the molecular sequences classification system
Phylogeny- evolutionary relationships between organisms
cladistics- when similarity in molecular sequences is used to define a group of organisms
predation
prey numbers regulate predator numbers
presance of predators impacts ecosystem dynamics
competition
organisms within an ecosystem use the same resources
both species are negatively affected
symbiosis
symbiotic relationships exist between species and have at least 1 member benefiting
mutualism- both benefit
commensalism- one benefits, other unaffected
paratism- one benefits, other is harmed
Disease
the harm to a living thing and can involve the interatction between a pathogen and a host
Clade definition
group of organisms that includes an ancestor and all the proposed decsendants of that ancestor, also known as a monophyletic group
what are the common assumptions of cladistics
common ancestry-organisms within a group are decended from a common ancestor
Bifurcation- there is a bifucating pattern (dividing a branch into 2)
Physical change- physical change occurs over time
describe a cladogram
More Simplistic then Phylogram
No time scale
Molecular evidence
if two species have similar proteins or DNA sequences it is used as molecular evidence that they shared a recent common ancestor.
What are ecyosystems composed of?
Habitats:
Microhabitats- very small habitats
Ecoregions- ecosystems covering large biogeographical areas
How are ecosystems classified
The interaction of organisms and the abiotic factors
how is the process of classifying ecosystems an important step towards effective ecosystem management
It helps to understand the importance of an ecosystem and understanding the unique interactions and the steps requried to preserve them.
Example: Old growth forests protect many endagered species and logging is not permitted to prevent habitat destruction and the relase of large amounts of carbon dioxide.
how can ecosystems be compared
spatial scale- comparing across areas
temporal scale- comparing across time
species interaction- predation, symbiosis, compettition, disease
Abiotic factors- climate, soil type, precipitation, light levels
what is the purpose of stratified sampling
estimate:
population
distribution
enviromental gradients/profiles
zonation
stratification
Site selection in stratified sampling
sites must be selected from each strata that are fairly homogenous and representative of the larger population
randomisation is used to minimise bias
minimising bias when stratified sampling
Law of large numbers- greater number of samples = greater chance the samples represent the community
random number generators- used to pick grid coordinates for transects or quadrats
Counting Criteria- Establishing clear parameters for counting organisms
Calibration of Equipment- Regular servicing and calibration of equipment and acknowledgment of precision
choise of ecological surveying technique when stratifed sampling
Transects- measure change in distribution and abiotic factors
Quadrats- Measure density
Biodiversity
Biodiversity is the variety of organimsms living within an ecoystem, including the diversity of species and ecosystems
Determining diversity using percentage cover
measures the proportion of an area covered by an organism to measure abundance
Explain how environmental factors limit the distribution and abundance of species in an ecosystem
Each species has a set of enviromental conditions required for their survival known as a tolerance range.
Example- in a cold climate metabolism can be slowed and also slow growth of plants resulting in limited species being able to survive from limited food supplies
Determining diversity using percentage frequency
Measures the apperance of of plant species in quadrats.
Determining diversity using species richness
measures the number of species within an area`
Determining diversity using species abundance and evenness
-species abundance is the number of individuals of a species in the ecosystem
-Species evenness is a measure of individuals of a species in relation to the total number of all species in the area
Determining diversity using simpsons diversity index
SDI takes into account both species evenness and richness
A value of 0 means a monoculture of 1 species
a value of 1 indicates infinite diversity
