BIO 373 1st Edition Lecture 9 Outline of Last Lecture I Energy Continued a Heterotrophs i energy and digestion ii adaptations and morphology iii foraging theory Outline of Current Lecture I Life History a Complex life cycles b Classification c Survivorship curves d Grimes e Trade offs f Life cycle draw backs g Life cycle benefits Current Lecture Life History Life history overall pattern in timing and nature of growth reproduction and survival averaged across all individuals in the species o Variations in individuals within the species due to differences in Distribution of differences in growth ability to reproduce timing of maturity etc Genetic differences Environmental causes Phenotypic plasticity same genotype can generate different phenotypes depending on the environment Complex life cycles These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o Great morphological change during development animals and plants Ex Tadpole to frog Ex Haploid plant to diploid plant o Watch the cool videos from the slides Classification o Semelparous one bout of reproduction in lifetime Salmon agave marsupials octopus etc o Iteroparous can reproduce several times during life Humans birds mosquitos etc Survirorship curves o See curve on slides I high mortality at old age II constant rate of mortality birds III few make it to old age o r K selection r intrinsic rate of growth K carrying capacity of population r type III survivorship unstable environment density independent small organism size low energy usage many offspring produced early maturation short life expectance one reproductive event semelparous K type I and II survivorship exact opposite of type III survivorship Grimes model o Life history of plants o Characteristics of habitats Stress disturbance competition of habitat See slide with triangular model Tradeoffs o Tradeoff between number and size of offspring Negative correlation Allocation of energy can allocate more energy into size of organism and less into the number produced or vice versa We would not see a large organism with large number of offspring along with high survival rate fast maturation etc because there are resource and energy limitations Tradeoff is most visible where there is no parental care o Tradeoff between current and future reproduction the cost of reproduction higher investment in current reproduction hinders growth and survivorship and reduces future reproduction Investments in growth will pay off with higher number of offspring produced and reproductive bouts in the future o Tradeoff of senescence Senescence physiological decline with age until death Depending on when you are reproducing determines bout of senescence Organisms like humans senesce for a long time occurring after reproducing but during this period of senescence provide care to offspring Life cycle drawbacks o Parental investment Small offspring size makes them more susceptible to predation or other factors so parent invests in caring for offspring Life cycle benefits o Dispersal Colonizing new habitats distribution of species Planktonic vs nonplanktonic o Dormancy Can wait for the right conditions for reproduction or development