Anisogamy - unequal gametes, few expensive eggs, many cheap sperm Females usually invest more in growing and caring for each offspring Mate guarding - preventing other males getting access to fertile females Forced matings - rape in mallard ducks, male injection of sperm in Hemipteran bug Peacock's tail - impairs survival but attracts females Monogamy - European robin Evolution: Processes and Patterns Charles Darwin 1809-1882 Alfred Russel Wallace 1823-1913 Evolution - theory, hypothesis well supported by empirical evidence, different sources agree with one another (consilience) Evolution - process of temporal change over time with respect to any heritable traits/characteristics Heritable - characteristics passed on from parents to offspring, largely genetic and are often also expressed in the phenotype (can also be epigenetic effects - inherited maternally) Two processes of evolutionary change: Transformation (anagenesis) between-generation change within single lineages Splitting/branching (cladogenesis) division of a single lineage due to genetic divergence (has common ancestor) As time passes after anagenesis the two lineages alter and resemble each other less and less Cladogenesis - subsequent changes occur in both/either of sister lineages results in further divergence, division of lineage due to genetic divergence Division event - generally results in two new lineages or just one new lineage in addition to original Branched evolutionary histories - phylogenies Microevolution - at population level, species are comprised of one or more populations of many individuals, refers to within-species (intraspecific evolution) Includes the processes leading to speciation, ie production of new species Speciation occurs mainly through cladogenesis Macroevolution - at species level and above, ie interspecific evolution: Involves - speciation events (splitting of lineages) and subsequent divergence of species and higher taxa (genera, families) There is an overlap between micro and macro Traits - in evolutionary biological and population genetical parlance Characters - in taxonomic parlance
Genotype - information stored in the genes of one individual Info stored in all genes of one individual (Dawkins)/ combination of alleles at one or more studied locus in one individual (Mendel) Phenotype - observable/measurable/detectable characteristics of an organism other than its genes, ie any/all observable non-gene traits, eg external appearance, internal tissues, intracellular structures, proteins/polypeptides External structures eg nests - extended phenotype Cytological - chromosome morphology and number 'karyotype' and behaviour during meiosis Phenotype has been from a practical perspective the easiest to observe/record/quantify, until recently was the only observable part of organism Variation in most phenotypic traits is at least partly genetically determined and therefore heritable Heritability is measurable - proportion of the phenotypic variance that is due to genetic factors, eg morphology variation among individuals within peppered moth pop physiological - eg sensory trait colour blindness (varying degrees) eg bodily secretion - 95% east asians have dry ear wax, 97% european/africans have runny ear wax due to single nucleotide difference in gene ABCC11 eg behavioural, courtship display - displacement preening in male ducks eg molecular - human haemoglobin - alpha and beta polypeptide chain subunits (humans differ with respect to one nucleotide in beta chain) cytological - sickle cell