Unit 3, topic 1 Flashcards
define biodiversity
biodiversity refers to how many species work together in an ecosystem.
define species
species refer to a group of organisms that share a gene pool
what are the 3 types of biodiversity?
define each
genetic diversity refers to the range of different genes within a species.
species diversity refers to the range of different species within an ecosystem.
ecosystem diversity refers to the range of different ecosystems within a particular location
what are the consequences of low biodiversity?
inbreeding, vulnerability to disease, over predation and ecosystem breakdown.
what is the quadrat method
laying a 1mx1m square on a surface and sampling everything inside the square.
A sufficient number of quadrats must be sampled in order to provide an accurate sample.
what are transects
a straight line across the earths surface along which measurements are taken.
measurements must be taken at regular intervals in order to ensure accuracy.
what is species richness and what are its advantage and disadvantage
species richness refers to the number of species present in an ecosystem.
advantage:
- measures 0-infinity
- easy to count
disadvantage:
- does not take into account how many species are present or what their interactions are.
define species abundance and what are its advantage and disadvantage
refers to how many of species are present
advantage - allows ecosystems with a dominant to be differentiated from more evenly distributed systems.
disadvantage - more difficult to count.
define percentage cover and its advantage
refers to a percentage of a quadrat that a species os covering
advantage - grasses and other plants that are difficult to count are better approximated.
define percentage frequency and its advantage
refers to portion of quadrats that contained a particular species.
advantage - more accurate assessment of how abundant species a species is in the ecosystem.
define spatial scale and its types
how much area an ecosystem covers
macro - large area or water (ocean or continent)
meso - medium (dessert or lake)
micro - small (rainforest)
define temporal scales and its types
refer to the time period over which an ecosystem is studied.
long term - years
midterm - seasonal changes
short term - hours (eg. 24 hrs)
how can you compare ecosystems
diversity indices -SDI
species interactions -competition, predation, symbiosis, disease.
abiotic factors - climate, soil substrate, area depth/size.
How could two ecologists measure the biodiversity at the same location at different times and get different measurements?
human disturbance of diurnal organisms during daylight hours while nocturnal animals are undisturbed.
larger predation population takes advantage of sleeping nocturnal animals
animals are in hibernation
how could two ecologists measure biodiversity at different locations at the same time and get different measurements?
temperature differentiation across latitudes
salinity in oceans differs across latitudes or depths.
define limiting factor and examples
limiting factor refers to abiotic and biotic factors that restricts an organism from living in an area.
biotic - high predation population, limited food resources, competition
abiotic - temperature, soil salinity, low rainfall.
describe species richness
Species richness
Number of species
Easy to count
Measures 0-infinity
Does not take into account how many species are present and how they interact
relative species Abundance
Relative species abundance
Number of each species present
Calculating species abundance = number of species/ total number of species multiplied by 100.
Differentiates evenly distributed ecosystems from non-evenly distributed ecosystems (some ecosystems have one dominant species whilst others are evenly distributed).
More difficult to count
percentage cover
Percentage cover
Percentage of a quadrat that a species is covering.
Makes it easy to measure grasses and other plants that are difficult to count.
species diversity index
what is the formula?
Value closer to 1 = higher biodiversity
SDI = 1 _
where:
N = total number of organisms of all species
n = number of organisms of one species
Accounts for species richness and abundance.
describe spatial differentiation and the types
Spatial scale – how much area an ecosystem covers.
Types of spatial differentiation:
Macro-level ecosystems – large area of land or water (ocean or continent).
Meso-level ecosystems – medium area of land or water (dessert or lake).
Micro-level ecosystems – small area of land or water (rainforest).
describe temporal differentiation
Temporal differential
Temporal scale – the time period over which an ecosystem is studied.
Types of a temporal differentiation:
Long term – years
Midterm – seasonal changes/months
Short term – hours
how can you compare ecosystems
You can compare ecosystems and temporal scales using SDI, species interactions (competition, predation symbiosis, disease), abiotic factors (climate, substrate, size/depth of area).
how can species diversity be different at different times but at the same place
Measures of species diversity are different at different times but same place:
Human disturbance – diurnal organisms during daylight hours while nocturnal animals are undisturbed.
Predator population – it can be natural for biodiversity to be higher at night if a large predator population takes place during daylight.
Hibernation – animals may be hibernating at different times of the year.
how can measures of species diversity can be different at the same times but different place?
Measures of species diversity can be different at the same times but different place:
Climate/landscape can be different at the same time over different latitudes.
Salinity can be different in oceans over different latitudes
Animals occupy different ecological niches over different latitudes.
describe what a limiting factor is
Limiting factor
An aspect of the environment that restricts an organisms ability to live there.
All biotic and abiotic factors are a limiting factor to something.
EG: koala population are restricted by number of Eucalyptus trees living in urban bushland.
define taxonomy
Taxonomy – a system of classification
define taxon
Taxon – a level of hierarchical classification system (EG: family, kingdom, class).
why do scientists group organisms together
By grouping similar organisms together scientists can understand the range of life on earth, observe trends and patterns and understand relationships between groups of organisms.
what is a limitation of classification systems
Limitations – classifying requires biologists to emphasise major similarities which means some minor differences are ignored which creates a skewed view of reality (EG: skin colour).
define clade
Clade – refers to a group of organisms that share a common ancestor and all its lineal descendants.
describe the Linnaean system
Linnaean system originally envisioned all life as one of 3 domains: animal, vegetable or mineral, now the domains are Eukarya, Archaea and Bacteria.
The Linnaean system does not solely rely on physical features – it relies on phylogenetic order.
what is domain in the Linnaean system
Domain: highest
Eukarya – includes Eukaryotes where DNA is contained within the nucleus, organelles exist.
Archaea – includes Prokaryotes (organisms that lack DNA in nucleus and organelles). Live in extreme environments (EG: high salt or temperature environment).
Bacteria – includes Prokaryotes.
Organisms part of Achaea and Bacteria domains store DNA
and synthesise proteins differently.
what is kingdom in the Linnaean system
Kingdom: 2nd highest
Eukarya – Animalia, Plantae, Protista & Fungi.
Animalia – mammals, insects and sea sponges.
Plantae – have cell walls that contain cellulose and obtain energy from photosynthesis using chloroplasts, includes mosses, ferns and flowering plants.
Protista – single-celled organisms that live in aqueous environments includes Amoebae.
Fungi - characterised by having cell walls made up of chitin (polysaccharide), includes yeasts, moulds and mushrooms.
Archaea – microscopic, single-celled organisms known for living in extreme environments.
Bacteria – microscopic, single-celled organisms.
define binomial nomenclature
Binomial nomenclature – naming system (genus, species).
how do scientists classify organisms based on reproductive methods
Classification by reproductive methods (Asexual, sexual, K and r selection):
The class Mammalia is separated into 3 categories of how they give birth:
Eutherian (or placentals) - give birth to live young after the foetus is developed inside the mother (dog).
Marsupials – give birth to their young at an extremely early developmental stage and complete their development inside their mothers pouch (kangaroo, possum and koala).
Monotremes – offspring develops in eggs (platypus and echidna).
r/K selection – a form of mathematical classification based on the number of offspring a species produces and the level of parental involvement required to care for them.
how do scientists classify organisms based on molecular sequences
Classification by molecular sequences (molecular phylogeny/cladistics).
As Protein and DNA sequences are inherited from ancestors biotechnology can be used to show that whether an organisms share common ancestors despite physical differences. Sequences that are more similar show closer evolutionary relationships.
DNA sequences:
Four nitrogenous bases – adenosine, thymine, guanine, cytosine. The order of these bases determines physical and physiological features and contributes to individuality. Similarities help group organisms.
Protein sequences:
Amino acids make up proteins - Similarities in amino acid sequences help group organisms.
what are the 3 assumptions of cladistics
Assumptions of cladistics:
Common ancestry – all species are related to each other because they all diverged from one ancestry (they possess a common ancestor)
Common ancestor - A species whose offspring diverged over time.
Cladogenesis occurs dichotomously – clades bifurcate.
Phylogenetic tree – branching diagram showing evolutionary relationships.
Change in characteristics occurs in lineages over time.
what is a conserved sequence
Conserved sequences – a DNA or protein sequence that is preserved across species due to optimal function.
explain protein conservation
Proteins and the alleles that encode them are subject to evolution by natural selection.
A protein that is well suited to its function may be conserved over time while other traits around it may evolve. This is because mutations in this protein are more likely to hinder its function than improve it, and individuals with the hindered protein are less likely to survive than individuals with the better one.
Hence, two distantly related species that require the same protein function will have similar protein sequences.
For example – histones are positively charged proteins that DNA (which is negatively charged) wraps around to prevent all genes from being expressed all at once. DNA must be unwrapped from the histone for the enzyme involved in replication or expression to gain access to it. Mutation were to occur in the histone proteins could cause DNA to bind too loosely, not at all or too tightly (in which case the mechanisms involved in unwrapping the DNA from the histone would not be effective). These mutations would result in genetic changes so severe as to be incompatible with the rest of life.
explain dating divergence
Mutation rate – the estimated number of base pair changes per nucleotide per generation.
There is a baseline rate of mutations in DNA (including mitochondrial DNA).
If mutations change the structure or function of proteins, then they will change the way those proteins are passed onto the next generation and how common they are.
Neutral mutations – are mutations that are neither beneficial or harmful to an organism’s ability to survive. EG: mutations in non-coding areas.
When comparing the genome of two species, the mutation rate can be used as a molecular clock to estimate when those species diverged from a common ancestor.
Note – there can be high or low conservation.
explain molecular phylogeny
Bioinformatics is the digital storage, retrieval, organisation and analysis of data that can create a new version of a phylogenetic tree by a technique called molecular phylogeny which is based on the evolution of a single gene or set of genes rather than a species.
what is the biological species concept regarding the need for multiple definitions of species
Biological species concept – states that species are a group of organisms whose members have the potential to interbreed and produce viable offspring.
Limitations:
Cannot apply this to fossils of extinct animals because it is impossible to know if animals could interbreed with one another or whether physical differences can be attributed to individual variation or different species.
Hybrid organisms are the result of two different species interbreeding. - these hybrids do not displace either of their parents species and generally do not survive outside their hybrid zones. This offers evidence that the parents could be a single species as they can interbreed however their behavioural and physiological differences indicate they are different species. EG: polar bears interbreed with grizzly bears to produce grolar bears.
what is the morphological species concept regarding the need for multiple definitions of species
Morphological species concept – states the definition of a species is based on physical characteristics.
Limitation:
Scientists disagree which morphological structure should be used to compare organisms.
what is the phylogenetic species concept regarding the need for multiple definitions of species
Phylogenetic species concept – identifies a species as being the smallest clade, or smallest group of organisms who can all trace their origins back to a single common ancestor.
Limitation:
Does not take into account the reproductive capabilities between species.
Does not apply to cases where morphologically different populations are connected by gene flow.
provide an example of interspecific hybrid that does not produce fertile offspring.
Note - Species can be prevented from breeding due to nocturnal activity, intricate mating rituals or number of chromosomes.
Example of infertile species: mule (from horse and donkey)
Horses have 62 chromosomes and donkeys have 61, owing to the differences in chromosomes a zygote is formed with 63 chromosomes. Therefore, this odd number of chromosomes makes the mule uncapable of forming gametes during meiosis.
identify the species interactions
Species interactions:
Competition
Symbiosis
Predation
Disease
define competition
Competition – occurs when two niches of two individuals overlap and both require the same resources to fulfil their needs. EG: sea anemones fight for the same food.
define symbiosis (and the types)
Symbiosis – describes an interaction where at least one species benefits from the interaction.
Parasitism – one organism benefits at the expense of another (mosquitoes on skin)
Communalism – one is benefited and the other is neither is unaffected (remora fish attach themselves to sharks and gain transportation, protection from predators and leftover food scraps of sharks).
Mutualism – both species benefit (ox-pecker bird on zebra)
define predation
Predation - the predator kills and eats the prey.
define disease
Disease – pathogen (disease causing organisms) damage or kill their host.
what does the distribution of terrestrial habitats depend on
The distribution of Terrestrial habitats (on land) depends on climate variation.
Tundras
Desserts
Open forests
Temperate grasslands
identify the four main elements of climate
Four main elements of climate:
Water
Temperature
Light
Wind
describe the characteristics of a dessert environment
Dessert:
Temperatures range widely in desserts from below 0 degrees overnight to above 40 degrees during day.
Rain is unpredictable and infrequent, less then 150mm annually.
Poor soil - phosphorous and nitrogen, which nourish plant life, are present in the soil in considerably lower concentrations in the dessert due to the lack of organic detritus called humus.
describe the characteristics of a rainforest environment
Rainforest:
Temperatures remain stable in a rainforest, between 20 degrees at night and 35 degrees at day.
Receive lots of rain, 1500-2500mm annually.
Poor soil - humid and its nutrition are washed away from soil due to frequent precipitation, leading to character ally poor soil.
Humus - a dark brown organic matter derived from decomposed plants and animal remains.
what are the two types of aquatic habitats
Aquatic habitats
Includes marine and water freshwater environments.
describe the characteristics of a marine habitat
Marine habitats are are classified according to depth, distance from shoreline and the way they are formed.
The photic zone - first 200m of ocean depth. This is the only part of the water where light can penetrate and accommodate photosynthesising organisms.
Pressure increases as you go down deeper, light decreases and temperature decreases.
describe the characteristics of a freshwater environment
Freshwater environments: characterised by production of organic matter.
Large deep rivers tend to be more nutrient poor compared to shallow lakes but lend themselves eutrophication (increased concentration of nutrients, such as phosphates and nitrates, in a waterway, that promotes agal bloom). The resulting agal boom can reduce light penetration and oxygen concentrations causing negative effects of local species living in shallow lakes.
Salt concentration changes depending on the tide. High = high tide and low=low tide.
what are standing bodies of water characterised as
Standing bodies of water
Deep lakes are characterised by depth and can be divided into photic and aphotic zones.
why is ecosystem classification is important step towards an effective ecosystem management
Managing ecosystems
Australian terrestrial ecosystem are named according to specht’s classification system and then modified with the common name or genus name of the dominant species.
This allow ecologists to group similar ecosystems and habitats for study.
describe stratified sampling
Stratified sampling - a statistical sampling technique that divides an area into strata for separate sampling. - gives an accurate portrayal of an area. Stratified sampling can be used to measure:
Population size
Population density
Population distribution
Define environmental gradients
Define habitat zones
selecting and sampling data
Selecting and sampling strata
Boundaries - Consider how large the area is, boundaries between strata should be defined. EG: the boundary between high tide mark and upper beach sands. Obvious boundaries make it easier to determine if your sampling is going to be representative of the area.
Number of samples - the number of samples in each stratum should reflect their relative size.
Random sampling - should be used.
what are sampling techniques
Sampling techniques
Quadrants: square measurement at ground level (everything inside square is sampled).
Used to estimate distribution and abundance.
Used to measure stationary things.
Population density = average number of individuals per quadrant / size of each quadrant.
what are transects
Transects: Line drawn through a community to provide a boundary for sampling.
Used to determine the distribution of species within that community.
Useful for stationary measurements.
Quadrats may be placed at regular intervals along the transept line.
Can be horizontal or vertical.
what is the capture recapture method
Capture-mark-recapture:
Sampling method for mobile species (animals) that involves capturing a number of individuals, marking the, and releasing them, At a later date the same number of individuals are recaptured and the proportion of marked to unmarked is used to estimate the population size.
how to minimise error when sampling
Minimising error:
Sufficient quadrats should be taken in each stratum to ensure the same is representative.
The number of quadrats should be proportional to the size of the stratum.
Using a random number generator to determine the position of quadrats taken,
Any equipment should be calibrated immediately and the precision in the data should be noted.
how to present data
Presenting sampled data:
Table form:
Graph form: helps analyse relationship.
