Evolution

What are the different types of allometry (and what is allometry)?

(Allometry = relation between the size of an organism and the size of any of its features / parts) - Isometric growth: constant rate of change with size (a = 1, proportions stay the same - constant rate) - Positive allometry: increase in rate of change with size (a > 1, something gets proportionally larger through growth / age) - Negative allometry: decrease in rate of change with size (a < 1, something gets proportionally smaller with growth / age)

What are the different types of heterochrony (and what is heterochrony)?

(Heterochrony = change in the timing or rate of development) - Hypermorphosis: ontogeny ceases late - causes overdevelopment - Progenesis: ontogeny ceases early - causes underdevelopment - Acceleration: features grow at a faster rate (compared to rate in ancestor) - Neoteny: features grow at a slower rate (compared to rate in ancestor) Hypermorphosis and / or Acceleration produce Peramorphosis: exaggeration of adult features Progenesis and / or Neoteny produce Paedomorphosis: retention / exaggeration of juvenile features

What are the advantages and disadvantages of reading the fossil record?

- Advantages: all taxa can be incorporated, simple to implement, does not require knowledge of detailed phylogenetic relationships - Disadvantages: geological biases, anthropogenic biases (disproportionate sampling and study of certain "key" time intervals), historical biases (relating to the longer period of work in western Europe and North America), taxonomic artefacts (e.g. synonyms, misidentifications), temporal variation, spatial variation (global diversity analyses may obscure regional variations or diversity changes could occur simultaneously across the or may display a different pattern in each region)

Anagenesis and Cladogenesis definition What is punctuated equilibrium?

- Anagenesis (or Phyletic evolution) = gradual transformation (along branches) of one species into another - Cladogenesis (or Phylogenetic evolution) = splitting of a species into two or more lineages (at nodes) Evolution involves long stasis (equilibria), punctuated by rapid change during isolation and speciation

What were the triggers of the Cambrian explosion?

- Breaking up of the supercontinent Rodinia into smaller land masses produce more epicontinential environments (shallow water) = new niches to exploit - Prolonged glaciation event in late Precambrian may have caused oceanic upwelling - Increasing primary production and atmospheric oxygen level, Oxygen (and Ca2+) may have firstly enabled animals to construct large bodies and allowed synthesis of biomineralized skeletons - Hox genes are master controls which code for anterior-posterior development and differentiation of the metazoan body plan, development or mutation of just one Hox gene in the ancestral metazoan could potentially initiate a large morphological change in the animal, mechanism that released developmental constraints resulting in an explosion of body plans

What is a character and a state and what is the problem with using character states for a cladogram?

- Character = is the feature (e.g. feathers) - State = is the type of feature (e.g. brown feathers) The problems with character states are that not all characters are reliable guides to evolutionary relationships, similarity between taxa can be caused by convergence (homoplasy = character shared by a set of species but not present in their common ancestor), problems are caused by different evolutionary rates in different branches (some groups evolve faster than others so may look quite different but actually be quite closely related e.g. the whale and the cow)

Difference between cumulative and single-step selection

- Cumulative selection = each improvement is used as a basis for future building - Single-step selection = each new 'try' is a fresh one

Definitions of: Evolution Phylogeny Adaptation Natural selection Vestigial feature Exaptation Spandrel Developmental plasticity

- Evolution = Descent with modification - Phylogeny = Diversification of lineages through evolution - Adaptation = a trait that enhances fitness and that arose historically as a result of natural selection - requires feature, more offspring reproducing and that it appeared in conjunction with its current function in its environment (wasn't previously used for another function) - Natural Selection = gradual, non-random process by which biological traits become more or less common in a population through differential reproductive success (fitness) - Vestigial feature = structures or attributes that have apparently lost most or all of their ancestral function (e.g. the Blind Cave Fish has lost its eyes during evolution as it no longer needs them as lives in dark caves underwater so cannot see anything anyway) - Exaptation (AKA co-option, and preadaptation) = a feature of an organism that shifts its function during evolution (previously used for one thing, but now used for another) - Spandrel = a phenotypic characteristic that is a by-product of the evolution of some other characteristic, rather than a direct product of adaptive selection - Developmental plasticity = alteration of phenotypes during growth to match environments, can enhance evolution e.g. fish raised on land developed fins better suited to walking

What are the types of systematics?

- Evolutionary / "traditional" = classifies using an intuitive appreciation of ancestry & adaptation - modern synthesis incorporates Linnaean taxonomy with Darwinian evolution, emphasises orthogenesis and other ideas, fossil specimens as ancestors, keeps classification and phylogeny separate, key factors: phylogeny, degree of divergence, order of appearance in fossil record, and "overall adaptive level" - Phenetic (numerical taxonomy): classify organisms based on overall similarity, usually in morphology or other observable traits, regardless of their phylogeny or evolutionary relation - anything goes - Phylogenetic systematics or Cladistics: organisms are categorized based on shared derived characteristics that can be traced to a group's most recent common ancestor and are not present in more distant ancestors, simplest (parsimony) explanation

What were the major advances in our understanding of evolution and who discovered them?

- James Hutton = gradualism (profound change in the cumulative product of slow but continual process), the Earth was 'alive' not static (e.g. mountains formed by molten materials and could also be eroded...) - Jean-Baptiste Lamarck = 'inheritance of acquired characteristics' - idea that organism can pass on characteristics acquired during its lifetime teleological ideas - animals want to change - Georges Cuvier = established extinction and catastrophism (before this time, fossils were considered the remains of animals still alive on other continents), opposed evolution - Charles Lyell = popularised Hutton's gradualism as uniformitarianism (same natural laws and processes that operate today also operated in the past), mapped rock formations leading to the field of stratigraphy - Erasmus Darwin = suggested all warm-blooded animals have arisen from one common ancestry and have improved over time

What is Lagerstatten, the Signor Lipps effect and the Lazarus effect?

- Lagerstätten = deposits of lots of or exceptional preservation (e.g. soft tissue or feathers) - but problematic as causes huge peaks in diversity which may not be an accurate presentation of diversity - Signor Lipps Effect = can miss an extinction as there is often a gap in fossil records between a true extinction and the last fossil record from that species - Lazarus Effect = sampling bias leads to you thinking a species has gone extinct (but it hasn't) due to a lack of fossil records

Monophyletic and Paraphyletic definition

- Monophyletic = a taxon (group of organisms) which forms a clade, meaning that it consists of an ancestral species and all its descendants - Paraphyletic = a monophyletic group from which one or more subsidiary clades is excluded to form a separate group

What were the propositions underlying Darwin's theory of evolution through natural selection?

- More individuals are produced than can survive, causing a struggle for existence (competition) - Individuals within a species show variation, those with advantageous traits will survive and reproduce, favourable traits will accumulate over generations - Changes in environment can lead to new traits being advantageous (It needs: natural variation, environment, time, survival and reproduction, evolution)

What are the Panspermia and Primordial Soup explanations for how life began?

- Panspermia = the theory that life on the earth originated from microorganisms or chemical precursors of life present in outer space and able to initiate life on reaching a suitable environment - Primordial Soup = the early Earth had a chemically reducing atmosphere (no O2), this atmosphere, exposed to energy in various forms, produced simple organic compounds ("monomers" e.g amino acids), these compounds accumulated in a "soup", which may have been concentrated at various locations (e.g. shorelines), by further transformation, more complex organic polymers (e.g. RNA) and ultimately life developed in the soup - the Miller-Urey experiment showed that this could have actually happened, but later studies showed that it couldn't have occurred on Earth due to the difference in atmosphere

What are the alternative explanations for adaptations?

- Phylogenetic constraints (inherited from ancestors but not needed e.g. human appendix) - Design constraints prevent the optimal - Sexual selection (e.g. peacock tail) - Neutral features (not required for anything but just there) - Co-variation with other traits (long arms = long legs due to hormones) - Exaptation (old feature used for new function e.g. pandas thumb) - Random genetic drift (founder effect - large population shrink due to chance event which causes a change in genes)

What were the main features of the past few eras?

- Precambrian - little oxygen in atmosphere so the earliest organisms were anaerobic, when photosynthesis evolved in bacteria this introduced oxygen to the atmosphere and allowed organisms to develop aerobic respiration - Cambrian - explosion ~545 million years ago, sudden appearance of complex animals, hard-bodied animals abundant, most modern phyla; Chordata, explosion probably due to environment e.g. increased O2 and Ca2+ - Silurian - ocean diversification and invasion of land (~440 - 350 million years ago), plants then arthropods conquer land - Devonian - the "Age of the Fishes" and first tetrapods - Permian - "Great Dying", 90-95% of species extinct, Pangaea forms, 10 - 30ᵒC hotter than today, extensive volcanic activity, large amounts of CO2 and SO2 , 700,000-year period - Mesozoic - "Age of the Reptiles", marine reptiles, dinosaurs, mammals, birds, flowering plants, mass extinction ~65-66 million years ago - Cenozoic - "Age of the Mammals", mammals radiate across the globe, first grasslands (~50 million years ago), humans ancestors/hominins (~5 million years ago), Ice Age and mass extinction (~2 million years ago)

What are the adaptations and type of adaptations made by animals transitioning from land to water?

- Propulsion - body undulation vs. flapping, undulators have long bodies to maximise thrust they develop but flappers have much shorter ones to minimise drag - Locomotion - great convergence; long limbs with small feet good for terrestrial locomotion broad, strong but flexible paddle needed for aquatic locomotion - Respiration - Cetaceans have more haemoglobin in their blood and more blood in their body to store more oxygen (just having larger lungs causes problems for buoyancy so many animals have dense skeletons to offset the positive buoyancy of their lungs, some also rely on swimming downwards) - Fertilisation - seawater kills sperm; leave the water to mate (but not if fully aquatic), lay eggs on land (must have something to act as a limb to allow them to move on land), give birth to live young (must be precocious - able to swim and reach surface to breath quickly or will drown)

What are the sources of random and non-random variation?

- Random = mutation, duplication, regulation and recombination, segregation and independent assortment - Non-random = ontogeny (things that happen in your life that are programmed to happen e.g. age, growth), phenotypic plasticity (environment induces change e.g. running gives you endurance), heterochrony (timing of growth) and allometry (differential rate of change with size)

What are the types of hybridisation?

- Reinforcement = if hybrids were infertile then the two species would eventually stop interbreeding and the species would diverge - Fusion = the hybrid would cause the original two species to go extinct, leaving just the daughter species - Stability = hybrids would survive and be fertile enough to be able to breed with either species so the species would become slightly similar but slightly different (due to the sharing of alleles among the 2 species)

What are the different types of character state?

- Synapomorphy - derived character states that are shared among taxa e.g. tetrapods possess limbs with digits - Autapomorphy - derived character states that are restricted to a single lineage - contains no information on grouping or how the group is related to other groups as it is a unique feature (e.g. wings) - Plesiomorphy - shared, primitive state / ancient feature e.g. vertebrates primitively lack limbs; this (absence) feature contains no information on grouping within vertebrates - Homoplastic/homoplasy - a state that evolves multiple times (convergence) e.g. mammals and birds evolved endothermy independently of one another

Teleology definition Aristotle, the Old Testament and Linnaeus (Carl von Linne) views on evolution

- Teleology = any philosophical account that holds that final causes exist in nature, measuring that design and purpose govern nature (e.g. goal-directed evolution) - Aristotle - 'scala naturae' - each form of life has its allocated rung on a ladder of ever increasing complexity (teleology) are permanent, species are permanent and perfect, and do not evolve - Old testament - all organisms resulted from the direct actions of a creator and were individually created by God (creationism), each organism has its specific role and fits perfectly in its environment because it was 'hand-crafted'(teleology) , the Earth is ~6000 years old, Universe is ~13,000 years old - Linnaeus (Carl von Linne) = taxonomy (finding, describing and naming species, hierarchical), binomial nomenclature (name composed of 2 parts in Latin e.g. equus caballus) - kingdom, phylum, class, order, family, genus, species

What were the changes in opinion on evolution during Darwin's time? What was accepted and debated in Darwin's time, and what were the alternative explanations?

- Universe no longer static; constantly changing - End of teleology - Species are not fixed; gradation among all things - Earth was ancient - Humans and animals not separate - Uniformitarianism ruled - Biology as science and philosophy - Dawn of Metaphysical Naturalism - Accepted in Darwin's time: evolution happens, common ancestry and descent, species can change - Still debated: pace of change, mechanism(s) of change - Alternatives: Lamarckism (transformation) Saltation (giant leaps) Orthogenesis (teleology; linear)

1. What was Mendel's law of dominance? 2. What was Mendel's law of segregation? 3. What was Mendel's law of independent assortment?

1. In a cross of parents that are pure for contrasting traits, only one form of the trait will appear in the next generation 2. During the formation of gametes, the two alleles responsible for a trait separate from each other. Alleles are then recombined at fertilization, producing the genotype for the trait of the offspring 3. Alleles for different traits are distributed to gametes (and offspring) independently of one another

What were the 'Big 5' mass extinctions (according to Sepkoski)?

1. Ordovician-Silurian: Gondwana moves south, global cooling, glaciation and sea level falls, approximately 400 MYA, 85% of marine species extinct, severe icehouse world, 2 pulses relating to beginning and end of glaciation (glaciation caused extinction and warmer climate caused another extinction) 2. Late Devonian: cause and extent uncertain, only affected marine life, approximately 370 MYA, 75% of species extinct, possibly several waves of extinction or spread over a long time interval (possibly deep sea anoxia?) 3. Permian - Triassic: 96% of marine and 70% of terrestrial species extinct, various causes-- e.g. global temp rise to bolide impact, approximately 250 MYA 4. Triassic - Jurassic: cause debated e.g. sea fluctuation, bolide, volcanism, approximately 200 MYA, 50% of species extinct, many archosaurs went extinct, except dinosaurs, pterosaurs and the group leading to crocodiles 5. Cretaceous - Tertiary: dinosaurs die out etc, bolide impact and volcanism?, 66 MYA, 75% of species extinct

Species definition What is a ring species?

A group of organisms whose members are descended from a common ancestor and who all possess a combination of certain defining, or derived, traits - uses the concept of Cladogenesis (or branching of species), encompasses Morphological Species Concept A connected series of neighbouring populations, each of which can interbreed with closely sited populations, but for which the two "end" members in the series are unable to successfully interbreed (species tend to be hard to differentiate at the boundary of their population)

Trend and clade definition What is the 2 types of clade competition?

A long term directional change within a clade and between clades (trends do not imply a goal in evolution!) (Clade is a group of organisms believed to comprise of all the evolutionary descendants of a common ancestor) Direct competitive exclusion: increase in clade 2 causes decrease of clade 1 Incumbent replacement: extinction of clade 1 enables clade 2 to diversify

What was the evolution of the human?

Adaptations for walking bipedally, smaller canine teeth > Enlarged cheek teeth and jaws > Massive cheek teeth and jaws, enlarged chewing muscles > Slightly larger brain, more vertical face without a snout, fingers capable of precision grip, ability to make simple stone tools > Smaller jaws and cheek teeth, long legs and arched feet well-suited for long-distance walking and running, larger brain > Large brain, small face tucked below brain case, rounded cranial vault, small brow-ridges, language

What was Bergmann's rule and Allen's rule?

Bergmann's Rule: species of larger size are found in colder environments, and species of smaller size are found in warmer regions Allen's Rule: animals in colder climates usually have shorter limbs (or appendages) than the equivalent animals from warmer climates

What is a species-area relationship? What is Island Rule and why does it occur?

Bigger area = more species / Smaller area = less species (by Van Valen) Large species become smaller when they move to an island, small species become larger when they move to an island (or are stranded on it) occurs due to covariation of: - resource limitation - reduced predation - reduced inter-specific competition (competition between different species) - immigrant selection (and founder events), optimal body size

What is the difference between the Red Queen and the Court Jester?

Biotic interactions (Red Queen): living factors are the most important drivers of evolutionary change- e.g. competition - tends to cause smaller changes such as microevolution - explains how organisms adapt over time but don't become any better at surviving as their environment and competing organisms also evolve at a similar rate to them ("evolutionary arms race") - "it takes all the running you can do to keep in the same place", e.g. a parasite doesn't want to kill the animal it lives in, because it needs it to survive, but the host evolves better ways of fighting off the parasite so it is more likely to survive. But parasites that evolve better ways of defending themselves are also more likely to survive etc.... Abiotic perturbations (Court Jester): non-living factors are the most important drivers of evolutionary change- e.g. bolide impact, tectonics - tends to cause large scale changes such as macroevolution, - while an animal may be very well suited to its environment, that's not much use, as if the environment changes then you will die out, and something else will take your place e.g. random events such as the asteroid strike that wiped out the dinosaurs, the strike itself, and the consequent widespread destruction, left the world wide open for the mammals, and they rapidly evolved to take advantage of their good fortune, taking over environments that they'd never previously had a chance to colonise

What are the main animals that have made the transition from land to sea (complete and partial)? What is an endemic species?

Complete: whale, manatee Partial: seal, hippo, otter, beaver, platypus, water opossum, penguin, turtle, crocodile Endemic species = species that are only found on a particular island (or particular group of islands) - most islands have at least one endemic species

What was the evolution of the lizard?

Early reptile --> Lepidosaur --> Rhynchocephalians + Squamata Early reptile --> Archosaur --> Pseudosuchia + Ornithodira --> Pterosaur + terrestrial dinosaurs - Synapsids went extinct during Permian "Great Dying", made Archosaur new dominant form of life - Pseudosuchia most successful by Triassic period - Pseudosuchia went extinct at the end of the Triassic period, allowed the Ornithodira to become dominant, Crocodylomorphs also survived and became successful in Jurassic and Cretaceous periods - Pterosaurs appeared in late Triassic and were the first non-insects to conquer the air - Mass extinction at the end of the Cretaceous period wiped out all non-avian dinosaurs, pterosaurs and non-crocodilian crocodylomorphs - Rhynchocephalians successful during Mesozoic but mainly went extinct after Cretaceous extinction, also outcompeted the Squamates

What is Genetic Drift and Genetic Flow? What is a genetic bottleneck and the founder effect?

Genetic Drift = Changes frequencies of alleles due to chance alone, reduces variation / genetic diversity Genetic Flow = Moves alleles from one population to another, increases variation / genetic diversity - Genetic bottleneck - population size is reduced drastically and quickly, which causes the allele frequency of the progeny of the survivors to be reduced - reduced variation - Founder effect - a few individuals from a population start a new population, which reduces variation as the allele frequencies are lower than in the original population

What was the Lamarckian evolutionary theory? What is the modern synthesis theory of evolution?

Lamarck = 'Inheritance of acquired characteristics' - Species changed over time to produce new ones, need-produced change (e.g the need to be able to climb), changes were acquired to meet these needs by individuals and then passed to offspring Modern synthesis = Introduced the connection between two important discoveries; the units of evolution (genes) with the mechanism of evolution (selection) - genetic variation in populations arises by chance through mutation, gene segregation and recombination, evolution consists of changes in the frequency of alleles between one generation and another due to genetic drift, gene flow and natural selection, most genetic changes have individually slight phenotypic effect, diversification comes about by speciation

What was the evolution of the tetrapod?

Lungfish > Panderichthys > Tiktaalik > Acanthostega > Ichthyostega > Tulerpeton > Living Tetrapods (Lungfish) Single, large limb bone / lobe fin > (Panderichthys) Two smaller limb bones > (Tiktaalik) Weight-bearing elbows, wrist and neck > (Acanthostega) Forelimbs and hindlimbs with digits, pelvis, loss of scales > (Ichthyostega) Gill lost and tail fins reduce > (Tulerpeton) Tibia and fibula, development of wrist and ankle > (Living tetrapods) Five digits, further development of limbs

What are the adaptations of mammals?

Many early mammals were small and active at night (nocturnal) so good sense of hearing would have been beneficial, developed 2 ear bones (hammer/malleus and anvil/incus, the third bone, the stirrup/stapes was already present), vibrations captured by the tympanic membrane (ear drum) and amplified by the ear bones and transmit the vibrations to the footplate/oval window and hence to the inner ear, Amniotes split into two major clades: 1) Diapsid reptiles which gave rise to reptiles, 2) Synapsids that gave rise to mammals, thus mammals evolved from reptile-like (synapsid) ancestors, these 2 extra bones came from jaw bones in mammalian ancestors (shown in fossil records)

What are the differences between Darwin's and Modern Synthesis' theories?

Modern synthesis recognizes several mechanisms of evolution in addition to natural selection, it recognizes that characteristics are inherited as discrete entities called genes, variation within a population is due to the presence of multiple alleles of a gene, it postulates that speciation is (usually) due to the gradual accumulation of small genetic changes (this is equivalent to saying that macroevolution is simply a lot of microevolution)

What were Gregor Mendel's ideas on evolution and inheritance?

Offspring traits are a blend of parent's traits. This means that favourable traits would be diluted in a population over several generations and Darwin's theory of evolution should not really work. Also found that plant offspring retained traits of their parents and that physical traits are retained by "particles"

What are the benefits of sexual selection?

Over time genomes of an asexual population accumulate deleterious mutations in an irreversible manner known as genetic loading; once the load gets too heavy the population goes (theoretically) extinct, in a sexual population, genetic material is recombined which prevents mutational deterioration, sexual reproduction also allows you to evolve quicker and out compete / out evolve asexual organisms

What are the pre-zygotic/pre-mating barriers? What are the post-zygotic/post-mating barriers?

PRE: Habitat isolation (populations live in different habitats and do not meet) Mechanical isolation (structural differences in genitalia of some organisms prevent copulation) Behavioural isolation (little or no sexual attraction between males and females) Temporal isolation (mating occurs at different times of the day or season / year) POST: Gamete incompatibility (sperm fails to penetrate egg) Hybrid mortality (hybrids sometimes just die) Hybrid fertility (offspring not fertile so is not classed as a distinct species) Hybrid breakdown (after a few generations the hybrids stop becoming fertile)

What was the evolution of the primate?

Plesiadapiformes (first primate-like mammals, small squirrel-like primate ancestors, 55-65MYA, insect eaters, possibly nocturnal, arboreal and ground dwelling forms, their decline was caused by competition with rodents, climactic conditions and the appearance of the first true primates and with bats) --> Adapiforms (cat-sized primates ancestors, 55MYA, show all of the anatomical characteristics of living primates) --> Eosimias (45 MYA, small, insect-eating, arboreal quadruped, with a small brain and long snout) --> Aegyptopithecus (35 MYA, resembled modern day New World Monkeys) --> Proconsul (25-10 MYA, ape-like and monkey-like features) --> Pierolapithecus (13 MYA, last common ancestor of all great apes, shows many similarities between all living apes, including adaptations to specialised climbing)

What were the adaptations during the evolution of the tetrapod?

Reduction of midline fins occurs early, loss of operculars and detachment of head from shoulders (i.e. a 'neck') occurs before loss of fin rays, gain of digit-like elements, and re-orientation of fin to anterior position, development of the pelvis and enlargement of the hind limb lags behind loss of operculars etc. after development of a neck, lengthening of snout, enlargement of eyes, changes associated with air breathing, occur while the animals retain fin rays, and are still mainly (if not entirely) aquatic, morphology of Acanthostega also suggests digits evolved while the animals were mainly (if not entirely) aquatic, backbone changes?, primitively limbs were polydactylous not pentadactylous, breathing not locomotion was the first modification to occur

Sexual and Artificial Selection definition

Sexual Selection = Animals develop features to help them to maximise their reproductive success - make them more attractive to opposite sex (e.g. peacock tail) or deter or defeat same-sex rivals (e.g. deer antlers) - intersexual selection = between the sexes, intrasexual selection = within in given sex Artificial Selection = Intentional breeding for certain traits or combination of traits (e.g. domestication of the horse)

What is speciation and what are the different types of speciation?

Speciation = occurs when geographically separate population become genetically different - Allopatric = geographical speciation (dispersal = the movement of a few members of a species to a new geographical area, resulting in differentiation of the original group into new varieties or species, vicariance = the separation of a group of organisms by a geographic barrier, resulting in differentiation of the original group into new varieties or species) - Sympatric = no geographical isolation but populations still diverge (e.g. blue indigobird lay eggs in the nests of other finches, and then learn the songs of their respective finches - they can still mate with one another but females prefer suitors who know the same finch song they do, they then pass their preferences on) - Peripatric: (similar to founder effect) - some of the original population move to a new separate / isolated habitat - Parapatric: some of the original population move to a new adjacent habitat

What are the main 6 species concepts? (And what is a species concept?)

Species concepts (a way of defining a species) - Biological = possessing reproductive isolation - Phylogenetic = possessing independent lineage (cladogenesis) - Morphological = possessing a distinctive form (has its own individual phenotype) - Ecological = possessing a distinctive niche - Nominalism = uses just names, methods do not matter (not real entities) - Evolutionary significant units = focuses on distinct populations and doesn't worry about species concepts

Taxonomy and Systematics definiton

Taxonomy = practice of naming organisms and groups; classification - no evolutionary component required, hierarchical (almost always), no other links to biology needed; just a naming system for reference - Linnaeus used 'Ranks' (e.g. species, genus, family, order, class) to encode hierarchical structure, based on similarity or the presence of shared features (e.g. feathers, hair, scales) Systematics = study of the history of organisms, including taxonomy, biogeography, evolutionary relationships (phylogeny), etc.

What is an ecological niche, what are the different types of ecological niche and what are the types of niche competition?

The ecological role and space that an organism fills in an ecosystem, includes an organism's life history, habitat, and place in the food chain, no two species can occupy the same niche in the same environment - Fundamental (theoretical) niche: full range of environmental conditions and resources an organism can possibly occupy and use, without limiting factors - Realised (actual) niche: part of fundamental niche that an organism occupies as a result of limiting factors present) - Competitive exclusion: to coexist in a stable environment two competing species must differ in their respective ecological niche - Character displacement: divergence of characteristic/traits in two similar species living in overlapping ecological niches

What are the Hardy-Weinberg assumptions? What is the Hardy-Weinberg equation?

The population is large (i.e., there is no genetic drift), there is no gene flow between populations, from immigration or emigration, there are no mutations or they are negligible, individuals are mating randomly, no selection Frequency of allele A (dominant): p Frequency of allele a (recessive): q p + q = 1 / (p + q)2 = 12 p2 + q2 + 2pq = 1

What are the adaptations of whales?

They are artiodactyls (even toed ungulate), some whales still have tiny parts of their pelvis and femur present from when they used to have legs millions of years ago, also have reduced inner ear sensitivity as they no longer need the hearing to air their balance as they are no longer land mammals so don't have the risk of falling over, their blowhole has also migrated from their nostrils (at the end of their nose) all the way up to their head 1) Shorter legs; powerful tail 2) Fresh water to salt water 3) Nasal opening shifts back; eyes lateral 4) Tail fluke; very small hindlimbs; nasal open retreats further; reduced semi-circular canals 5) Loss of hindlimbs; posterior blowhole - have also developed echolocation and baleen lunge feeding (baleen is similar to bristles in their mouth - act as 'teeth') and ability to open jaw very widely

What are the adaptations of birds?

Uni-directional breathing; air sacs provide the lung with oxygenated air at all times - pneumatic (or hollow) bones are evidence of air sacs, these were both present in non-flying dinosaurs which birds still have today, quill knobs are variably present in extant (surviving) bird species, so their absence does not necessarily indicate a lack of feathers, their presence, however, is a direct indicator of feathers of modern aspect, quill knobs have been found in various non-avian theropods which were incapable of flight-- e.g. Velociraptor, this provides clear evidence that feathers evolved before the origin of flight and that the first feathers did not serve an aerodynamic function (used for? insulation, heat shielding, communication, crypsis, water repellency, and defence), non-avian theropod feathers are proposed to have evolved for sexual display and perhaps thermoregulatory function; this implies theropods might have been endothermic, hence maybe heat retention was the primary function of early "protofeathers"