http://watchingtheworldwakeup.blogspot.com/2008/08/unbearable-lightness-of-aspen-part-1.html

Sciurus carolinensis

Gray squirrels

• Reproduce sexually• Diploid organisms with

haploid gametes.• Reproduce Dec-Feb

and June-Aug• Litters of 2-4 pups• Pregnancy lasts 40-44

days• Pups are weaned by

10-12 weeks• General squirrel info

• Squirrels will chase each other to establish dominance (spiral chasing around tree), play, and as a type of mating ritual (slower paced).

• Both male and female squirrels are polygynandrous (promiscuous), although once ejaculation occurs, a mucus plug forms over the vagina preventing further mating.

• The squirrel population has gotten so large and has led to damage of trees. As a result, immunocontraception is being tested as a mechanism of population control.

Asclepias syriaca (Milkweed):The Basics of their Reproduction*Part of the kingdom Plantae and reproduce sexually

by pollinating the seeds held within a pod (see right)

*Follow a diploid→haploid→diploid pattern (plant→seeds/pollen→fertilized zygote)

*The number and quality of flowers in an inflorescence (complete flower head of a plant) is directly correlated to the number of viable seed-filled pods (up to 30 flowers)

*Self fertilization in possible for milkweed, as is typical cross breeding between two separate milkweed plants

* Because of the pods, milkweed utilize a “high-cost, low-risk” manner of reproduction-- see next slide

The High-Cost, Low-Risk Phenomenon *All seeds in a milkweed are stored together in pods, each containing up to 100 seeds!*Why “high-cost”? If the pod is damaged or for any reason cannot be fertilized, a loss of not just one but up to 100 seeds occurs. *Why “low-risk”? The stability and structure of the pod prevents loss in most circumstances. *The benefits of the pod outweigh the risk; the development of this is thought to be an evolutionary adaptation

to increase sexual fitness.

Sources Used:Wilson, Mary, Rathcke, Beverly. 1974. Adaptive Design of the Floral Display in Asclepias syriaca L. American Midland Naturalist. Vol. 92, p.48.Kilps et al. 2004. https://bioweb.uwlax.edu/bio203/s2013/baumann_brea/reproduction.htm.

ANAX JUNIUS-COMMON GREEN DARNER

One of the most common dragonflies in North America

Widespread Found from Alaska to

southern parts of Central America

Distinctive differences between males and females Males have a bright blue

abdomen Females have a reddish

brown abdomenhttp://www.arkive.org/common-green-darner/anax-junius/http://animaldiversity.ummz.umich.edu/accounts/Anax_junius/#physical_descriptionhttp://www.nps.gov/miss/naturescience/greendarner.htm

Residential and Migratory Home for early summer South for the winter!

Copulation on vegetation Male grabs female by top

of the head or prothorax “Wheel” position Laying the eggs

Flying in tandem Jealous males Suitable aquatic

environments Multiple batches of eggs

HONEY BEE (Apis mellifera)

All bees are able to reproduce BUT this “job” in the hive falls to the queen bee (only female with fully developed ovaries) Up to 2,000 eggs a day and up to 1,000,000 eggs in

her lifetime Mates with males, called drones, midair

Can mate with a number of different males Sometimes copulation between honey bees can be

audible to the human ear as a popping noise because of the force of the ejaculation

Male dies after copulation

Fertilized eggs will develop into female bees while reared, unfertilized eggs will turn into male bees Female bees are diploid Male bees are haploid

Larvae hatch in about3-4 days and are then fedby worker beesDifferent castes of bees emerge at different times

Queens: 15-16 days, Workers: 21 days, Drones: 24 days

http://climatekids.nasa.gov/bees/

Daphnia- “Water Fleas”

• Order Cladocera- water crustaceans

• Live in fresh water• Found almost anywhere that

open fresh water is found• Over 150 species

documented in the United States

• Have one compound eye• Eat phytoplankton and algae• Very prolific due to their

ability to reproduce by cyclic parthenogenesis

Anatomy of female Daphnia (greatly magnified); diagrammatic. B, brain; BC, brood chamber; C, digestive caecum; CE, compound eye; F, fornix; FA, first antenna (antennule); H, heart; INT, intestine; O, ocellus; OV, ovary; R, rostrum or beak; SG, shell gland. (Fig 1 was greatly modified from Storch, 1925.)

What is Parthenogenesis???

• Parthenogenesis– A form of asexual

reproduction– Offspring are exact

replicas, or “clones” – Embryo develops from

an unfertilized egg and directly into an adult

– Stable environments perpetuate successful genotypes

• Application to Daphnia– Evolutionarily advantageous to

benefit during “favorable” conditions

• Depends on temperature and availability of food

• Late spring, summer, and early autumn

• Only females are produced at this time

– Females reproduce as early as 4 days old, and birth 10 live young as often as every 3 days

– Can produce up to 25 broods in on lifetime

Cyclic Parthenogenesis

• Reproduction by parthenogenesis- only in favorable conditions to produce generations of diploid females

• In unfavorable conditions, some ovum develop into haploid males

• Females produce haploid eggs that must be fertilized by the haploid males (sexual reproduction- increases variety), and are then shed from the female in carapace cases known as an ephippium

• The ephippium embryos are in suspended animation and can survive freezing and drought conditions

• Once conditions improve, live young emerge from the ephippium and the male sex dies out entirely until environmental stress returns

http://bioweb.uwlax.edu/bio203/2010/carroll_chri/reproduction.htm

Grape Phylloxera• Insect that reproduces sexually and asexually• Two different kinds of females: winged and wingless

How it works:• In spring, a wingless female hatches from a fertilized

egg that had been laid on the stem of a grape vine. (Produced sexually)

• She migrates to a leaf where she produces a gall and grows to maturity in about 15 days.

• She fills the gall with eggs and dies. • Nymphs that hatch from these eggs escape from the

gall, and wander to new leaves where they in turn produce galls and eggs.

• This may create 6 or 7 generations during the summer. • In the fall, nymphs migrate to the roots where they

hibernate through the winter.

http://www2.ca.uky.edu/entomology/entfacts/ef222.asphttp://www.annualreviews.org/doi/abs/10.1146/annurev.ento.46.1.387

• The following spring they become active again and produce root galls. • Wingless females may cycle indefinitely on the roots year after year. • In late summer and fall, some of the root inhabiting females lay eggs that

develop into winged females. • These winged females migrate from the roots to the stems where they lay

eggs of two different sizes. • The smaller eggs develop into males and the larger eggs into females. • Mating occurs and the female lays a single fertilized egg that winters on

the grape stem.• It is this egg that gives rise to leaf inhabiting generations. • It is important to note that phylloxera cycle continuously as root

inhabitants. • So while they can cycle continuously on the roots without leaf forms occurring, leaf inhabiting forms do not occur without the root form also occurring.

Lady Fern (Athyrium Filix-femina) life cycle

• Haploid spores grow under leaves

• Spores drop to ground; grow into heart-shaped gametophytes

• Gametes develop on gametophytes

• Gametes are fertilized (becoming diploid); grow after 2-6 months into the structure we typically think of as the fern plant (which is the sporophyte)

• Under the leaves of the diploid sporophyte grow haploid spores, and cycle repeats

http://www.ncbi.nlm.nih.gov/books/NBK9980/

Lady Fern (Athyrium Filix-femina) reproduction

• Ferns are either hermaphroditic or of a single sex (can be affected by pheromones)

• Reproduce via “selfing” or “crossing” means (depending on if the gametes come from gametophytes of the same or different sporophytes)

• “Selfing” fertilization can be intergametophytic (gametes come from different gametophytes) or intragametophytic (gametes come from the same gametophyte)

• Water is required for fertilization• In a 10-yr experiment with the three types

of breeding, intergametophytic crossing progeny showed the lowest adult mortality rates (with greatest heterozygosity of offspring); this type of reproduction is most common

Schneller, Johann Jakob. "Biosystematic investigations on the lady fern (Athyrium filix-femina)." Plant Systematics and Evolution 132.4 (1979): 255-277.Schneller, Johann Jakob, and Rolf Holderegger. "Vigor and survival of inbred and outbred progeny of Athyrium filix-femina." International Journal of Plant Sciences (1997): 79-82.Schneller, J. J. "Spore bank, dark germination and gender determination in Athyrium and Dryopteris. Results and implications for population biology of pteridophyta." Botanica helvetica 98.1 (1988): 77-86.

Harvestmen: Daddy Long-legsArachnid/Opillione/Phalangiidae• Live up to 1 year• Sexual Reproduction• Two sexes: male has penis, female has ovipositor• Mating: nuptial giftf; face-to-face; male can be rejected; up to three

minutes• Oviposition: can take up to five hours; 60-210 eggs; mother guards for up

to two months, and father can help guard too• Hatchlings: incomplete metamorphosis with several molting cycles• U of Maryland Harvestman Webpage