Unit 3, topic 1 Flashcards

Question

how can measures of species diversity can be different at the same times but different place?

Answer 1

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.

Answer 2

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.

Answer 3

Taxonomy – a system of classification

Answer 4

Taxon – a level of hierarchical classification system (EG: family, kingdom, class).

Answer 5

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.

Answer 6

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).

Answer 7

Clade – refers to a group of organisms that share a common ancestor and all its lineal descendants.

Answer 8

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.

Answer 9

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.

Answer 10

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.

Answer 11

Binomial nomenclature – naming system (genus, species).

Answer 12

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.

Answer 13

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.

Answer 14

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.

Answer 15

Conserved sequences – a DNA or protein sequence that is preserved across species due to optimal function.

Answer 16

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.

Answer 17

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.

Answer 18

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.

Answer 19

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.

Answer 20

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.

Answer 21

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.

Answer 22

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.

Answer 23

Species interactions: Competition Symbiosis Predation Disease

Answer 24

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.

Answer 25

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)

Answer 26

Predation - the predator kills and eats the prey.

Answer 27

Disease – pathogen (disease causing organisms) damage or kill their host.

Answer 28

The distribution of Terrestrial habitats (on land) depends on climate variation. Tundras Desserts Open forests Temperate grasslands

Answer 29

Four main elements of climate: Water Temperature Light Wind

Answer 30

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.

Answer 31

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.

Answer 32

Aquatic habitats Includes marine and water freshwater environments.

Answer 33

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.

Answer 34

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.

Answer 35

Standing bodies of water Deep lakes are characterised by depth and can be divided into photic and aphotic zones.

Answer 36

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.

Answer 37

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

Answer 38

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.

Answer 39

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.

Answer 40

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.

Answer 41

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.

Answer 42

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.

Answer 43

Presenting sampled data: Table form: Graph form: helps analyse relationship.