Required examples from specification Flashcards
These are all the required examples I could find in the Biology IB 2025 specification. Some say to include local examples or at least 1 so for those I gave examples learnt from lesson time
1
Q
What are the example organisms to convey the consequences the varying physical properties of water have on animals in aquatic habitats?
A
Black-throated loon
Ringed seal
2
Q
What are the examples to demonstrate the diversity of structures within viruses?
A
Bacteriophage lambda, coronaviruses and HIV
3
Q
What is the example for the lytic cycle of a virus?
A
Bacteriophage lambda
4
Q
What is the example for the lysogenic cycle of a virus?
A
Bacteriophage lambda
5
Q
What is the example to demonstrate rapid evolution in viruses?
A
Influenza and HIV
6
Q
What are the examples to show the diversity in chromosome numbers of plant and animal species?
A
Humans having 46 chromosomes
Chimpanzees having 48 chromosomes
Within evolution 2 ancestral ape chromosomes fused to form the human chromosome 2
7
Q
What is the evidence for evolution from homologous structures?
A
Pentadactyl limb
8
Q
What is the example to evidence that convergent evolution is the origin of analogous structures?
A
Wings for flight in a bird and wings for flight on an insect e.g butterfly
9
Q
What is the example to demonstrate the roles of reproductive isolation and differential selection in speciation?
A
Separation of chimpanzees and bonobos by the Congo River
10
Q
What is the example to demonstrate the barriers to hybridisation and sterility of interspecific hybrids as mechanisms for preventing the mixing of alleles between species?
A
A mule
11
Q
What is the example to depict the abrupt speciation in plants by hybridisation and polyploidy?
A
Knotweed or smart weed (genus Persicaria)
12
Q
What is the example to expose the causes of anthropogenic species extinction?
A
Northen giant moas (example of the loss of terrestrial megafauna) due to hunting by humans and changes within their habitat by deforestation so went extinct 600 years ago
Caribbean monk seal (loss of marine species) due to hunting for their meat and oil and extinct in 1952
Woolly mammoth went extinct due to climate change post ice age and was hunted by early humans
Silphium plant in Libya but went extinct because ancient greeks used it for birth control
13
Q
What is the example to show how chemical properties of carbon atoms allow for the formation of diverse compounds upon which life is based?
A
Examples of molecules with branched or unbranched chains and single or multiple rings
Branched: Glycogen
Unbranched: Cellulose
Single rings: Glucose
Multiple rings: Steroids
14
Q
What is the example to depict the production of macromolecules by condensation reactions that link monomers to form a polymer?
A
Examples of polysaccharides, polypeptides and nucleic acids
Polysaccharides: Glycogen, cellulose, chitin. starch
Polypeptides: Insulin, Haemoglobin, Glucagon, ligase
Nucleic acids: DNA or RNA
15
Q
What is the example to show the form and function of monosaccharides?
A
Glucose which emphasises solubility, transportability, chemical stability and yield of energy from oxidation
16
Q
What is the example to show the role of glycoproteins in cell-cell recognition?
A
ABO antigens
17
Q
What is the example to demonstrate the ability of non-polar steroids to pass through the phospholipid bilayer?
A
Oestradiol/oestrogen and testosterone
Should be able to identify these compounds as steroid by identifying the 3, 6 carbon rings bonded to the 5 carbon ring
18
Q
What is the example to demonstrate the infinite variety of possible peptide chains?
A
There are 20 amino acids so lots of possible combinations
Should be familiar with examples of polypeptides e.g insulin, titin, collagen
19
Q
What are the examples of Quaternary structure of non-conjugated and conjugated proteins
A
Insulin and collagen are non-conjugated
Haemoglobin is conjugated
20
Q
What is the example of simple diffusion across membranes?
A
Oxygen and Carbon dioxide
21
Q
What is the relationship between fatty acid composition of lipid bilayers and their fluidity?
A
Unsaturated fatty acids have kinked hydrocarbon tail so lipids harder to pack together, lowering viscosity and increasing fluidity
Saturated fatty acids no c=c so straight hydrocarbon tails so easier to pack together, increasing viscosity and lowering fluidity.
Many organisms will adjust composition of lipids to regulate membrane fluidity by homeoviscous adaptation and the general trend is an increase in unsaturated fatty acids at lower temperatures and an increase in saturated fatty acids at higher temperatures
Regulating membrane fluidity is particularly important in poikilothermic organisms whose internal body temperatures vary considerably (e.g. Antarctic fish)
22
Q
What is the example to demonstrate membrane fluidity and fusion?
A
Endocytosis and exocytosis from across the course e.g phagocytosis and pinocytosis and secretion of neurotransmitter from presynaptic neuron and secretion of hormones
23
Q
What are the examples of gated ion channels in neurons?
A
Nicotinic acetylcholine receptors (neurotransmitter gated ion channel), sodium and potassium voltage-gated channels
24
Q
What is the example of the use of the sodium-potassium pump?
A
Pump 3 x Na+ out of axon and 2 x K+ into axon to generate -70mV resting potential
25
What are the examples of the use of sodium-dependent glucose cotransporters?
Example of indirect active transport e.g absorption by cells in the small intestine and glucose reabsorption by cells in the nephron
26
What is the example as to why compartmentalisation in the cytoplasm of cells is crucial?
Protects the unwanted digestion from lysosomes and phagocytic vacuoles
27
What is the example for the location of stem cell niches in adult humans?
Bone marrow, epidermis of skin, hair follicles
28
Where have adaptations undergone to increase the surface area to volume ratio of a cell?
Proximal convoluted tubule cells in nephron due to microvilli
Erythrocytes due to bioconcave in shape
29
What is the example joint for the movement at a synovial joint?
Human hip
30
What is the example of an antagonistic muscle pair that facilitates internal body movements?
Internal and external intercostal muscles
(or circular and longitudinal muscles in peristalsis)
31
What are the reasons for locomotion?
Foraging for food- Sheep, deer
Escaping from danger- rabbit fleeing a fox
Searching for mate- birds of paradise
Migration- Salmon migrating upstream to mate or birds
32
What are the adaptations for swimming in marine animals?
Streamlining
Adaptation of limbs to form flippers and of tail to form fluke
Changes to airways allowing periodic breathing between dives
33
What are the examples for the adaptations of organisms to abiotic environment of their habitat?
Marram grass - horizontal underground stems that go very deep to provide anchorage and access water reservoirs. Leaves curled to decrease SA to reduce exposure of stomata to reduce transpiration in windy conditions. Stomata in pits to reduce transpiration loss and grasses are low growing to reduce exposure to wind and provide anchorage in sand
Mangroves - Parts of roots above ground to absorb oxygen, salt tolerant/halophytes so can sequester salt in cell to minimise osmotic disruptions, contain salt glands eliminating salt and deep penetrating tap roots specialised to exclude salt uptake
34
What are the abiotic variables affecting species distribution?
Limiting factor is component of ecosystem that limits distribution or numbers of a population
Abiotic factors can act as limiting factors:
Light intensity
Temperature
Soil pH
Wind speeds
Carbon dioxide and oxygen concentrations
35
What are the factors affecting the formation of coral reefs?
Water depth
pH
Salinity
Clarity
Temperature
36
What are the conditions that characterise a tropical forest?
Tropical forest - Hot climate (25-30 consistently), high levels of precipitation >250cm/year, very high levels of diversity in both animal and plant species
37
What is a biome?
Biome = groups of ecosystems with similar communities due to similar abiotic conditions and convergent evolution
38
What are the examples for the adaptations to life in hot deserts?
Saguara cactus have thick, waxy cuticles to decrease loss of water by evaporation and have reduced leaves to spines to minimise transpiration. Wide, vertical stems with water storage and avoids overheating. Tap roots that are wide spread to collect max water
Kangaroo rat have kidneys with longer loop of henle improving water retention, producing more concentrated urine, most active at night spending days in burrows away from heat
Camels store fats in hump to reduce isolation of body tissues preventing overheating
39
What are the examples for the adaptations to life in tropical forests?
Kapok tree grows above canopy and supported by buttress roots
Epiphytes grow on tree branches to compete for access to light and lianas have roots in the ground but use existing trees to grow tall and access light
Spectacled owl nocturnal and relies on other senses in low light conditions
Spider monkeys have smaller structure and limbs suited for climbing due to dense vegetation. Hook like thumbless hands to grasp lianas + branches and pick fruit. Highly developed larynx for communication in dense forest
40
What is the example of mixotrophic nutrition in some protists?
Euglena
41
What are adaptations of plant forms for harvesting light?
Trees that reach canopy, lianas, epiphytes, strangler epiphytes, shade-tolerant shrubs and herbs on forest floor
42
What are examples of anabolic and catabolic reactions?
Anabolism:
Protein synthesis, glycogen formation, photosynthesis
Catabolism:
Digestion and oxidation of substrates in respiration
43
What are examples of intracellular and extracellular enzyme-catalysed reactions?
Intracellular:
Glycolysis, krebs cycle
Extracellular:
Chemical digestion
44
What are examples of cyclical and linear pathways in metabolism?
Linear:
Glycolysis
Cyclical:
Krebs and calvin cycle
45
What is an example of competitive inhibition as a consequence of an inhibitor binding reversibly to an active site?
Statins act as competitive inhibitor, inhibiting enzyme, resulting in lowering of cholesterol levels
46
What is an example of the regulation of metabolic pathways by feedback inhibition?
Feedback inhibition = end product inhibition
Production of isoleucine from threonine where isoleucime acts as non-competitive inhibitor to 1st enzyme for cascade of reactions. This binding however is reversible
47
What is the example of mechanism based inhibition as a consequence of chemical changes to the active site caused by the irreversible binding of an inhibitor?
Mechanism based inhibition = non-competitive inhibition = suicide inhibition
Penicillin binds to the allosteric site of enzyme transpeptidase, permanently inhibiting it preventing the synthesis of cell wall in bacterium so bacteria lyses as can no longer regulate hydrostatic pressures.
48
What is example for the cell signalling by bacteria in quorum sensing?
Bioluminescense in marine bacterium, vibrio fisheri. Bacteria forms mutalistic relationship w/ bobtail squid creating camouflage for squid, whilst bacteria are provided w/ sugars and amino acids
49
What are the examples to show the chemical diversity of hormones and neurotransmitters?
Hormones:
Can be amines, steroid based or proteins
Neurotransmitters:
Can be amino acids, peptides, amines, nitrous oxides
50
What is the neurotransmitter than binds to transmembrane receptors and changes membrane potential?
Aceytlcholine receptor than open Na+ channel leading to Na+ to go into post synaptic neuron causing potential difference to become +ve
51
What is the transmembrane receptor used in tyrosine kinase activity?
Insulin binds causing phosphorylation of tails forming a dimer leading to movement of vesicles containing glucose transporters to the plasma membrane
52
What are examples of intracellular receptors that affect gene expression?
Oestradiol/Oestrogen, progesterone, testosterone
53
What are the examples of the regulation of cell signalling by positive and negative feedback?
Positive feedback:
An effect increases the stimulus which causes more of the effect to occur
e.g In childbirth, stretching of cervix by contractions has positive feedback of secretion of oxytocin so more contractions, Blood clotting, Ovulation as FSH has +ve feedback on secretion of oestrogen
Negative feedback:
An change detected by receptor and an effector is activated to induce an opposite effect promoting equilibrium
e.g Thermoregulaiton, Blood sugar regulation, Osmoregulation
54
How can you change speed of nerve impulses and what are the examples of these?
Make diameter of axon larger e.g Giant axons of squid
Smaller non-myelinated nerve fibres. Much slower than myelinated neurons
Conduction speed of nerve impulses is negatively correlated with animal size, but positively correlated with axon diameter.
55
What is the example on how there is a generation of an excitatory postsynaptic potential?
The binding of acetylcholine to transmembrane receptors once it diffused across synaptic cleft
56
What are the effects of exogenous chemicals on synaptic transmission?
Neonicotinoids that block synaptic transmission
Cocaine that blocks the reuptake of neurotransmitter
57
What is the example of cells, tissues, organs and body systems as a hierarchy of subsystems that are integrated in a multicellular living organism?
This integration is responsible for emergent properties and cheetahs become an effective predator by integration of its body systems
58
What is the example of the involuntary responses with skeletal muscles as the effector?
Pain reflex arc
59
What is the example for the maintenance of concentration gradients of phytohormones?
Phytohormones act as signalling chemicals controlling growth, development and response to stimuli in plants.
Auxin efflux carriers maintain concentration gradient. Auxins can freely diffuse into plant cells but not out of them and auxin efflux carriers are positioned in cell membrane only on one side. If all cells coordinate to concentrate these carriers on the same side,
auxin is actively transported from cell to cell through the plant tissue and becomes concentrated in part of
the plant.
60
What are the examples of mechanisms of HIV transmission?
Transmitted by the exchange of bodily fluid onto an open surface by unprotected sex, sharing of needles or can also be from mother to child during pregnancy, birth or breastfeeding.
61
What are examples of zoonoses as infectious diseases that can transfer from another species to humans?
Tuberculosis, rabies, Japanese encephalitis and most recently COVID-19
62
What are examples of resources that may limit carrying capacity?
Density dependent factors: (PANDA)
Predation
Access to habitats
Nutrient supply
Diseases
Accumulation of wastes (metabolic by-products can be toxic)
Density independent factors:
Drought, wildfires, hurricanes, deforestation
63
What are examples of cooperation in intraspecific relationships?
Leaf cutter ants leave trail pheromones to signal to other ants route to leaf source
Bald eagles calls attract other bald eagles who help to defend against predator
Vervet monkeys give alarm calls to warn other colony members of predator. Have different calls for leopard vs eagle
64
What are examples of competition in intraspecific relationships?
Male gorilla prohibits other males from accessing a mate by using physical aggression
In dense spruce forests trees compete fiercely for light. leading to survival of only most vigorous plants which grow over others shading them
65
What are the examples for each of the categories of interspecific relationship within communities: herbivory, predation, interspecific competition, mutualism, parasitism and pathogenicity?
Herbivory -animal eating plant - cows eating grass
Predation - animal eating animal - wolf eating hare
Interspecific competition - 2 or more different species competing for a resource - Lions and cheetahs in savanna hunt same antelope and gazelle
Mutualism - 2 species interacting to benefit both - Root nodules in Fabaceae, mycorrhizae in Orchidaceae, zooxanthellae in hard corals
Parasitism - one species benefits but the other is harmed - barnacles
Pathogenicity - one species causes a disease in the other - Measles, smallpox, typhoid
66
What are the examples of mutualism as an interspecific relationship that benefits both species?
Root nodules with Rhizobium bacteria in Fabaceae (legumes). Legumes growing in soil w/ low N2 density allow nodules to grow on roots to house bacteria which fix N2 into NH3 and donate to plant for building molecules e.g proteins or nucleic acids. Roots give sugars to bacteria
Mycorrhizae in orchidaceae.
Fungus possesses long filaments, called hyphae, that connect to the plant roots forming an association called a micorrhizae
Hyphae greatly increase SA of roots so more absorption, while the fungus gains carbs and sugars from the plant
Zooxanthellae in coral polyps. Zooxanthellae share nutrients from p/s w/ coral supplying carbon compounds, glucose, and Amino acids.
Coral polyps secrete CaCO3 exoskeleton providing shelter + protection for zooxanthellae and act as source of CO2 and ensure reliable source of sunlight as corals grow towards surface of the sea.
67
What is an example of resource competition between endemic and invasive species?
Japanese knotweed
68
What is an example for the predator-prey relationships as density-dependent control of animal populations?
Wolves and hares
69
What is the example of allelopathy and secretion of antibiotics?
Allelopathy: Garlic mustard
Secretion of antibiotics: Fungi e.g Penicillium chrysogenum work by mechanism based inhibition, inhibiting transpeptidase
70
What is an exmaple of the use of light as an external energy source in photoautotrophs and oxidation reactions as energy source in chemoautotrophs?
Iron-oxidising bacteria (chemoautotroph)
71
What is an example of mutations that have caused a change in protein structure?
PKU or sickle cell anemia
72
How can the initiation of transcription at the promoter be controlled?
Transcription factors that bind to the promoter alter initiation
73
What are examples of non-coding sequences in DNA that do not code for polypeptides?
regulators of gene expression, introns, telomeres, genes for rRNAs and tRNAs in eukaryotes
74
What is an example of how polypeptides by undergo modification before they can function?
The two stage modification of pre-proinsulin to insulin
75
What are examples of causes of gene mutation?
Proofreading Errors
During DNA replication, DNA polymerase will detect and remove any incorrectly paired nucleotides. If a damaged or incorrectly incorporated nucleotide is not replaced it will alter the DNA sequence, resulting in a gene mutation
Mutagens
Physical: Certain forms of radiation, e.g X-rays and (UV) light
Chemical: Substances e.g reactive oxygen species, certain metals (e.g. arsenic) and alkylating agents (which can be formed by grilling meat)
Biological: Some viruses (e.g. HPV) and certain bacteria (e.g. Helicobacter pylori) can induce mutations
76
How can mistakes in DNA replication be fixed?
During DNA replication, DNA polymerase will automatically detect and remove any incorrectly paired nucleotides
During DNA replication, the enzyme responsible for copying the DNA sequence (DNA polymerase) will automatically detect and remove any incorrectly paired nucleotides
If the polymerase fails to reverse the incorrect pairing, the offending nucleotide can still be replaced after DNA synthesis is completed via a process known as mismatch repair
77
What are examples of the use of CRISPR sequences and enzyme Cas9 in gene editing?
Gene technology to help cure sickle cell anemia, make disease resistant crops but must consider ethics before implementation and there's an international effort to harmonise regulation of the application of genome editing technologies such as CRISPR.
78
What is an example for an error that occurs in meiosis?
The non-disjunction event that occurs in anaphase 1 causing down syndrome
79
What is an example of cell proliferation for growth, cell replacement and tissue repair?
Proliferation for growth within the plant meristems and early-stage animal embryos. Occurs in skin as cell proliferation occur during cell replacement and during would healing
80
What are examples of epigenetics tags?
The methylation of cytosine in the DNA of a promoter represses transcription and therefore expression of gene downstream
Methylation of lysine amino acids in histones causes transcription to be repressed or activated
Acetylation of lysine amino acids in histones causes transcription and gene expression to be increased.
81
What is an example of environmental effects on gene expression in cells and organisms?
Alteration of methyl tags on DNA in response to air pollution e.g nitrogen oxides or polyaromatic hydrocarbons
The effects are easily shown in the investigation of effects of environment on monozygotic twins
82
What is the example to show the consequence of removal of most but not all epigenetic tags from the ovum and sperm?
The phenotypic differences in tigons and ligers (lion-tiger hybrids)
83
What are the examples of external factors impacting the pattern of gene expression?
Biochemical: Presence of lactose or tryptophan in bacteria
Hormones: Peptide hormones as diffuse into cytoplasm as non-polar and trigger alteration of gene expression
84
Who is attributed with the discovery of linked genes?
Thomas Hunt-Morgan
85
What are the examples of the medical applications of isotonic solutions?
Use of intravenous fluids which are given as a part of medical treatment and used in the bathing of organs reading for transplantation
86
What are examples of traits in organisms displaying the phenotype as the observable trait of an organism resulting from genotype and environmental factors?
Caused by genotype: Colour of human eyes and human blood types
Caused by environment: nutrition as flamingos become pink due to shrimp that they eat
Caused by environment and genotype: Human skin colour
87
What is an example of a human disease caused by a recessive allele?
Phenylketonuria (PKU) caused by mutation in autosomal gene that codes fro enzyme needed to convert phenylalanine to tyrosine
88
What is an example of multiple alleles?
ABO blood groups and denoted by I^A, I^B, i
89
What is an example of incomplete dominance?
Four o'clock flowers or snapdragons that result is the blend in phenotypes. Snapdragons when red crossed with white resultant offspring are pink
90
What is an example of codominance?
Human ABO blood groups
91
What is an example of a sex-linked genetic disorder?
Haemophilia and is carried on the X chromosome. It's recessive
92
What is an example of continuous variation due to polygenic inheritance or environmental factors?
Human skin colour
ABO blood groups are examples of discrete variables
93
What is an example of the role of hormones in homeostasis?
The regulation of blood glucose due to the secretion of insulin and glucagon by pancreatic endocrine cells
94
What is an example of negative feedback control?
Thermoregulation.
Process involves the peripheral thermoreceptors, hypothalamus, pituitary gland and thyroxin and skeletal muscles contract causing shivering, smooth muscles contract to cause vasoconstriction and adipose tissue acts as effectors of temp change.
95
What are examples of changes in blood supply to organs in response to changes in activity?
During sleep, kidneys, gut and skeletal muscles have reduced blood flow
During vigorous exercise, vasoconstriction to kidneys and gut and vasodilation to muscles
96
What are examples of abiotic factors that act as selection pressures?
Light intensity
Temperature
Moisture levels
Soil pH and mineral content
Wind intensity and direction
CO2 concentration
O2 concentration
97
What is an example to show how sexual selection can act as selection pressure?
The plumage of the birds of paradise as differences in physical and behavioural traits affect success of attracting a mate
98
What are the requirements for stability in ecosystems?
Supply of energy
Recycling of materials
Genetic diversity
Climatic variables within tolerance limits
Absence of disruptions which interfere with sustainability
99
What are examples to provide evidence of stability within natural ecosystems?
Boreal forests
Sahara desert
100
What is an example of a possible tipping point in ecosystem stability?
Deforestation of the Amazon rainforest
101
What are examples of marine ecosystem mismanagement and the assessment of resource harvesting from natural ecosystems?
North atlantic cod overfished depleting possible breeding and the replenishment of the ecosystem. Issue reduced by fishing quotas of maximum sustainable yield and exclusion zones placed so no fishing in nursery zones and enforcement of wide-hole nets so small cod could escape.
102
What are examples of terrestrial ecosystem mismanagement and the assessment of resource harvesting from natural ecosystems?
Softwood timber (e.g. hoop pine) is sustainably harvested at many plantation sites within Australia
Selective cutting of trees ensures in the canopy to promote regrowth and minimise soil erosion
Trees selected according to age to ensure there are enough trees remaining to flower and produce seeds
Replanting practices ensure logging doesn't outpace new growth
Ground measurement techniques and spatial modelling used to monitor and evaluate forest cover
103
What are the 2 examples of biomagnification in natural ecosystems?
DDT and mercury
104
What are examples of microplastic and macroplastic pollution of oceans?
Macroplastic is persistent and accumulates in oceans. It may be consumed and Laysan albatrosses feed plastic to chicks which are unable to regurgitate plastic which damages internal organs/intestines and animals become entangled in plastic. Degrades into microplastics that can be toxic and bioaccumulate
105
What is an example of the restoration of natural processes in ecosystems by rewilding?
The Hinewai Reserve in New Zealand
106
What are examples of the changes that occur during primary succession?
Increase size of plants
Amount of primary production
Increase in species diversity
Increase in the complexity of food webs
Increase in nutrient cycling
107
What is an example of cyclical succession in ecosystems?
Grazed woodland by cattle or deer and sapling grows in thorn bush so isn't eaten. Sapling grows into a tree and out competes the thorn bush. When tree dies, cycle restarts.
108
What is an example of arrested succession?
Grazing by farm livestock
Drainage of wetlands
109
What are examples of positive feedback cycles in global warming?
Snow melts so albedo decreases, more short wave UV absorbed and converted into IR heating atmospheric temperature so more ice melts
Permafrost thaws releasing CH4 and CO2 so increased absorption and trapping of IR so temperature increases so temperature increases for more permafrost thaws.
110
What is an example of a tipping point?
Change from net carbon accumulation to net loss in boreal forests
Warmer temperatures and decreased snowfall in winter cause increased frequency of drought and reduction of primary production in Taiga causing forests to brown and increased frequency of forest fires resulting in combustion of legacy carbon
111
What are examples of polar habitat change?
Melting of landfast ice and sea ice which means loss of breeding grounds for emperor penguins as early breakout of landfast ice in Antarctic and loss of sea ice habitat for walruses in Arctic and loss of hunting grounds for polar bears.
112
What are examples of poleward and upslope range shifts of temperate species?
Upslope range shifts for tropical-zone montane bird species in New Guinea
Range contraction and northward spread in North American tree species
113
What is an example of potential ecosystem collapse?
The threats to coral reefs as increase CO2 concentrations in atmosphere cause ocean acidification and suppression of calcification in Corals. Increases in water temperatures are a cause of coral bleaching as zooxanthellae are expelled and loss of corals causes collapse of reef ecosystems
114
What are examples of variables that influence the timing of biological events?
Photoperiod and temperature patters trigger biological events such as flowering, budburst and bud set in deciduous trees, bird migration and nesting
115
What is an example of the disruption to the synchrony of phenological events by climate change?
Temperature may act as a cue for one species and photoperiod may be cue for other
Spring growth of Arctic mouse-ear chickweed and arrival or migrating reindeer
Breeding of great tits and peak biomass of caterpillars in north European forests
116
What is an example of the number of insect life cycles within a year increasing due to climate change?
Spruce bark beetle
117
What is an example of evolution due to climate change?
Changes in the fitness of colour variants of the tawny owl as a consequence of changes in snow cover.
118
What are the adaptations of type 1 and type 2 pneumocytes in alveoli?
Type 1 are squamous and 1 cell thick for reduced diffusion distances and there is a high presence of secretory vesicles (lamlellar bodies) in cytoplasm of type 2 that secrete pulmonary surfactant into the alveolar lumen.
119
What tissue is an example of a tissue where more than 1 cell type is present?
Alveolar epithelium as there are type 1 and type 2 pneumocytes which are adapted differently to aid overall function of the tissue
120
How would you distinguish the relationship between dentition and diet of omnivorous and herbivorous representative members of the family Hominidae?
Students should examine models or digital collections of skulls to infer diet of extinct species from the anatomical features.
Omnivores have diverse dentition with sharp incisors and canines for tearing and flat molars for grinding whereas herbivores have large molars and premolars for grinding through vegetation
Examples may include Homo sapiens (humans), Homo floresiensis (unncooked plants and meat) and Paranthropus
robustus (plants e.g grass)
121
What are the 6 biomes?
Tropical forest
Temperate forest
Taiga
Grassland
Tundra
Hot desert
122
What are the conditions that characterise a temperate forest?
Moderate temperatures w/ clear seasonal changes, deciduous trees are dominant so fertile soil due to defoliation in autumn and high biodiversity
123
What are the conditions that characterise a taiga biome?
Cold and icy (0-15) w/ low rainfall but high snow fall, dominated by coniferous tress and little variation in species
124
What are the conditions that characterise a grassland?
Moderate temperatures w/ wet and dry seasons (moderate rainfall but seasonal droughts are common) Not enough water for significant tree growth, communities of grazing animals and some predators
125
What are the conditions that characterise the tundra biome?
Temperatures <0 and very little precipitation, vegetation consists of low growing plants (e.g mosses) w/ some hibernating and migrating species
126
What conditions characterise a hot desert?
Extreme temperatures, minimal rainfall <30cm/year, communities consist of few well adapted species (e.g xerophytes, a desert plant)
127
What can thrive in peat bogs due to the anaerobic conditions?
Methanogens which are obligate anaerobes and produce methane by methanogenesis.
Also thrive in cows stomachs
128
What are the 2 examples of a purine?
Adenine and Guanine (bigger than pyrimidine)
129
What are the 3 examples of pyrimidines?
Cytosine, Thymine, Uracil (smaller than purines)
130
What is a model that is used to investigate the effect of variables on ecosystem stability?
Mesocosm are enclosed environments that allow section of ecosystem to be observed under controlled conditions. Enable the testing of effect of conditions on an ecosystem e.g pH or light intenisty
Can be terrestrial mesocosms (terrariums) or aquatic mesocosms (aquariums)
131
What is a source of biodiversity?
Adaptive radiation allows closely related species to coexist without competing, thereby increasing
biodiversity in ecosystems where there are vacant niches.
132
What are examples of the loss of ecosystems as a consequence of direct or indirect anthroprogenic activity?
Loss of mixed dipterocarp forest in Southeast Asia due to logging and removal or trees to sell timber and to grow plantations
Amazon rainforest has undergone mass deforestation for timber, mining, housing, agriculture and is causing the increase in frequency of drought and disruptions to nutrient cycling. Without trees, increase surface run off which removes nutrients and can effect habitats hundreds of kilometres away.
Aral sea was 4th largest sea but in 60s 2 major rivers that fed the sea diverted for irrigation casing lake to decrease volume by 92% and 24 endemic fish now extinct and most invertebrate species disappeared.
