Antonie van Leeuwenhoek 1632-1723 Developed microscopes for observing living organisms 1674 discovered protists 1677 discovered spermatozoa 1682 discovered striated muscle fibers

http://www. molecularexpressions http://www.molecularexpressions.com/primer/images/introduction/leeuwenhoek.jpg http://www.cartage.org.lb/en/themes/Sciences/Physics/Optics/OpticalInstruments/Microscope/GlassSphere/usph_01.gif http://cell.sio2.be/introduction/images/microleeuw.jpg http://students.ou.edu/J/Renee.E.Jones-1/Van%20leeuwenhoek%20Scope.jpg

Schematic Human Sperm Cell http://academic.evergreen.edu/v/vivianoc/homunculus.gif Homunculus

Human (Homo sapiens) Sperm Photograph

Mammalian Syngamy: Plasmogamy

Calcium release spreading across an egg cell during syngamy

Amphioxus (lancelet) adult, zygote, and early cleavage not to scale!

Amphioxus (lancelet) cleavage

Amphioxus (lancelet) gastrulation and adult not to scale!

Morphogenetic movements of cells during development

Amphioxus (lancelet) nerulation

Primary Tissue Layer Tissue or Organ Ectoderm Mesoderm Endoderm Origin of some mammalian tissues or organs Primary Tissue Layer Ectoderm Mesoderm Endoderm Epidermis Muscle Lungs Hair Bone Liver Nails Blood Pancreas Eye lens Notochord Digestive lining Nerve system Kidneys Bladder Nasal oral mucosae Gonads Tissue or Organ

Frog (Rana pipiens) embryology

Frog (Rana pipiens) zygote

Frog (Rana pipiens) embryo: early cleavage

Frog (Rana pipiens) embryo: later cleavage

Chicken (Gallus gallus) zygote and early cleavage blastodisc yolk

Chicken (Gallus gallus) gastrulation

Chicken (Gallus gallus) embryo after 4 days of incubation

Human (Homo sapiens) embryo

Human (Homo sapiens) embryo

Human (Homo sapiens) embryo

Human (Homo sapiens) embryo

Comparison of vertebrate embryos of six species at 3 stages Ontogeny recapitulates Phylogeny

Typical sigmoid (S-shaped) growth curve: logistic curve plateau phase log phase Weight lag phase Age

Weight growth in a mouse (Mus musculus) Puberty 16 14 12 10 8 6 4 2 http://www.c-wilkie.pwp.blueyonder.co.uk/jokes/images/mouse_sex.gif Weight in grams Weaning http://www.sasionline.org/antsfiles/articles/images/Dino/mouse.jpg 5 10 15 20 25 30 35 40 45 Days after birth

Weight growth in an insect (Malanoplus) with 5 molts adult 150 100 50 Sudden increase when body lacks exoskeleton (soft shell crab) Weight (mg) 5 Nymphal instars: feeding 3 4 2 1 zygote 0 20 40 60 Age in days How does weight increase suddenly when not feeding?

Does growth continue indefinitely? Differential growth in weight of the Homo sapiens body and its parts 20 15 10 5 Body Does growth continue indefinitely? Why does the curve inflect here? Heart Multiples of weight at birth Brain 0 5 10 15 20 Age in years

Average decline in a Homo sapiens from age 30 to 75 years Characteristic Percent Decline Weight of brain 44 Number of nerve cells in spinal cord 37 Velocity of nerve impulse 10 Number of taste buds 64 Blood supply to brain 20 Output of heart at rest 30 Speed of return to normal pH of blood after displacement 83 Number of filtering subunits in kidney Filtration rate of kidney 31 Capacity of lungs Maximum O2 uptake during exercise 60

Three larval stages and a sea star adult (Asterias vulgaris) gastrula http://www.cbu.edu/~aross/embryo/s-gastrula-2.jpg gastrula benthic adult http://alpha2.bigelow.org/mitzi/images/library/subtidal%20animals/Sub-An-B_039.jpg planktonic larvae http://instruct1.cit.cornell.edu/courses/biog105/labs/deuts/media/echinowatervasc.jpg http://www.snv.jussieu.fr/bmedia/oursinMDC/coursours3/bipinn2leg.gif bipinnaria http://micro.magnet.fsu.edu/optics/olympusmicd/galleries/brightfield/images/starfishbrachiolarialarva.jpg brachiolaria

Monarch butterfly complete metamorphosis: zygote (“egg”) http://www.monarchwatch.org/update/2003/egg_glue1.jpg Danaus plexippus

Monarch butterfly complete metamorphosis: larva Danaus plexippus

Monarch butterfly complete metamorphosis: larva Danaus plexippus

Monarch butterfly complete metamorphosis: larva Danaus plexippus

Monarch butterfly complete metamorphosis: pupa Danaus plexippus

Monarch butterfly complete metamorphosis: adult Danaus plexippus

Monarch butterfly complete metamorphosis: adult Danaus plexippus

Incomplete (gradual) metamorphosis in grasshoppers zygote Incomplete (gradual) metamorphosis in grasshoppers Brachystola magna http://www.ent.iastate.edu/images/orthoptera/lubber.jpg

Relative DNA repair rate among mammals 100 (Homo sapiens) Human (Loxodonta africana) Elephant (Bos taurus) Cattle Life span in years (log scale) 10 Hamster (Mesocricetus auratus) Rat (Rattus norvegicus) Mouse (Mus musculus) 1 Shrew (Suncus murinus) Relative rate of DNA repair