ANSC 4090 - Exam 3 All Question Sets

How are wildlife affected by anthropogenic pollution, and what are some examples of chemical contaminants they face?

chemical contaminants from the manufacture, usage, and disposal of products including pesticides, pharmaceuticals, and heavy metals.

What are other sources of pollution affecting wildlife besides chemical contaminants?

• widespread anthropogenic light sources

• noise from traffic, machinery, and industrial activities

• heat pollution » alters thermal niches within ecosystems

T/F: A particularly concerning consequence of environmental pollution is the disruption of reproductive processes.

true

What traits necessary for reproductive success can pollutants interfere with?

• reproductive physiology

• gamete function

• organismal behavior

How can the alteration of reproductive processes affect mating success?

• direct: by decreasing fertilizations

• indirect: disrupting mate attraction and encounter rates

What is the term used to describe the number and quality of offspring an individual contributes to future generations?

the individual’s “Fitness”

T/F: Environmental pollution has no effect on reproduction or the production and signaling of sex hormones.

False

How can chemical pollutants affect steroid hormone receptors and sexual development?

interact with receptors directly or indirectly

• altering blood sex steroid levels

• disrupting sexual development

What are chemicals that alter blood sex steroid levels and disrupt sexual development called?

Endocrine-disrupting Chemicals (EDCs)

How does ethinyloestradiol affect wild fish?

• enters the environment via urine

• induces physiological feminization of wild males

  • interacts with oestrogen receptors

What types of chemical pollutants can mimic endogenous steroids and interact with hormone receptors?

• Bisphenol A and phthalates > interact with oestrogen receptors

• trenbolone and various prostate chemotherapeutic agents > interact with androgen receptors

How can pollutants change sex hormone levels?

• through stress related mechanisms

• affecting hormonal pathways

How can light pollution affect sex hormone production in birds?

• act as a chronic stressor

• inhibits the production of sex hormones through the HPA (Hypothalamic-Pituitary-Adrenal) Axis

What impact can change in sex hormone levels have on organisms?

affect reproductive anatomy development and morphology

What reproductive abnormalities were observed in American alligators exposed to a mixture of chemicals?

• Females: abnormal ovarian morphology and unusually prominent polyovular follicles

• Males: poorly organized testes and small phalli

What reproductive malformations can developmental exposure to the herbicide atrazine cause in amphibians?

male feminization > development of multiple gonads, altered testicular anatomy, ovotestes, testicular oocytes, and hermaphroditism

What are some examples of the direct impacts of chemical pollution on reproductive anatomy and morphology in different taxa?

• feminization of fish populations exposed to oestrogenic chemicals

• masculinization of gastropods exposed to anti-fouling paint

• reduced ovary development in wild bumble bee queens exposed to neonicotinoids

What does the evidence suggest about the impact of chemical pollution on sexual development in humans?

could be a major driver in reported increases in abnormalities in human sexual developement

T/F: Direct effects of pollution on wildlife reproductive anatomy and morphology are not limited to impacts of chemical pollution.

true

What impact has thermal pollution from nuclear power plants had on fish populations?

altered gonadal growth and asynchronic gonad and oocyte development

What effect does thermal pollution exposure have on gonad development in fish populations?

greater variation in gonadal development among many species

What effect does long-term exposure to noise pollution have on male reproductive anatomy in rats?

In adult male rats:

• decreased seminiferous tubule diameter

• reduced thickness of germinal epithelium

How can pollution affect sex determination and differentiation in wildlife?

disruption of cueing systems leading to biased sex ratios

In which species can temperature-dependent sex determination be affected by pollution?

fish, amphibian, and reptile species that rely on temp. for sex determination

What causes shifts in environmental temperatures affecting wildlife?

• global climate change

• local processes:

  • warm water discharge into rivers and estuaries from power plants

How do higher nest temperatures affect sex ratios in sea turtles?

skew sex ratios toward females

How can changes in environmental temperature influence the effects of chemical pollutants on sexual differentiation?

exacerbate the reproductive effects of chemical pollutants and thus, intensify their impact on sexual differentiation

How does the antifungal chemical clotrimazole affect sex ratios in zebrafish?

• skews sex ratios toward males

  • inhibition of aromatase production » aromatase converts testosterone to oestrogen

  • effect enhanced at higher temperatures

How can imbalances in sex ratios affect reproductive success?

by lowering encounter rates b/w males and females

How can altered sex ratios affect facultative sexual species?

may change the rate of sexual reproduction to asexual reproduction thus impacting genetic diversity

T/F: Exposure to environmental pollution can also alter reproductive timing in wildlife.

true

How does artificial light at night affect the reproductive timing of common blackbirds (Turdus merula)?

• after 1 year: seasonal gonad development occurred 1 month earlier than normal

• After 2 years: no seasonal development occurred

What other environmental factor, besides light, is used as a cue for biological events in many species?

Ambient temperature

How can increased temperatures from urban heat islands and global warming affect reproduction?

causes shifts in the timing (temporal shifts) of reproduction

What are the consequences of altered reproductive timing on offspring production and survival?

offspring production and growth may be de-synchronized from peak resource availability leading to reduced production and survival

How can the effects of pollutants on hormones and sexual development impact fertility?

can affect gamete function and consequently, fertility

What reproductive effects can exposure to oestrogenic pollutants have on male fish and female brown trout?

• Male: reduced sperm quality

• Female BT exposed to BPA: lower levels/delayed ovulation.

• Male BT exposed to BPA: reduced sperm density, motility rate, and swimming velocity

What effects does exposure to particulate air pollution have on human male fertility?

causes impaired sperm motility and damaged DNA structure/integrity

What effects does radiation pollution have on sperm?

• increased mutation rates

• reduced sperm production. quality, and motility

How can pollutants affect externally fertilizing species?

detrimental effects introduced through direct contact with sperm and/or eggs

How can the nanoscale pollutant titanium dioxide affect broadcast-spawning bivalves (Tegillarca granosa)?

attach to the oocyte surface, damage the plasma membrane, and reduce gamete fusion success

What is a particularly concerning aspect of certain environmental pollutants?

• long term impacts spanning across generations

• effects offspring health through epigenetic mechanisms

What evidence supports the long-term impacts of environmental pollutants on future generations?

• changes in sperm chromatin structure

• alterations in sperm small ncRNA content

• modified DNA methylation patterns in sperm

What pollutants have been shown to induce epigenetic changes in sperm?

• cigarette smoke

• ethanol

• vinclozolin (fungicide)

How can the epigenetic effects of environmental pollutants on sperm be mitigated?

can be partially reversed (depending on the toxicant, effect, and specific process affected) through exercise and environmental enrichment.

What do studies on transgenerational effects of environmental pollutants suggest?

pollutants can impact populations long after initial exposure and even removal of contaminant

How can pollutants affect animal sexual communication?

disruption of production, transmission, and detections of pheromones or other signal hormones used for locating mates

What is the consequence of inhibited pheromone production due to pollution?

reduced mate acquisition and mating success due to reduced reproductive receptivity

How can environmental pollution interfere with sexual communication beyond pheromone disruption?

interference with acoustic and visual signals used for sexual coms

How can anthropogenic noise pollution affect mating communication in animals?

• mask acoustic signals used for attraction

• damage auditory organs thus preventing perception of acoustic signals

  • affects spcs like fish, amphibians, birds, and mammals

How can light pollution and chemical pollutants affect mate selection in animals?

• light: reduce males perception of bioluminescent signals from females

• Chemical: 17 Beta-trenbolone can disrupt female preference for male color traits in spcs like guppies

How can environmental pollution affect parental care and offspring survival?

• reduces parental care leading to decreased offspring survival

• ex: seabirds » light and noise pollution cause decreased chick weights due to decreased parental feeding

What can lowered reproductive success due to pollution exposure lead to?

population decline and extinction

Do all reproductive effects of pollution reduce organismal fitness?

no » some effects are negligible as they pertain to fitness

What should future studies focus on for a better understanding of pollution's impact on reproduction?

• consideration of both biotic and abiotic interactions

• investigate the effects of pollutants over multiple generations

How can pollutants interact with other stressors?

can cause synergistic effects where the combined impact is significantly greater than the sum of their independent effects

What are the main objectives of assisted reproductive techniques?

• Increase reproductive efficiency

• Obtain offspring from individuals presenting reduced fertility

• Long term preservation of genetics/ biodiversity/ genetic diversity

In what industries/species/animals groups are assisted reproductive techniques being used?

• Human (Human fertility clinics)

• Farm animals

• Exotic animals

• Laboratory animals

Usually where in the female reproductive tract is semen deposited when performing artificial insemination (AI)? 

Uterus is preferred, but a lot of time can only get to cervix

Name 3 reasons for performing AI 

1. maximize fertility

2. increase genetic variability

3. reduced production cost and logistical ease

Insemination doses change between species. What are the two parameters that usually change between species when talking about AI doses?

• Sperm concentration 

• Volume 

What are the three “types” of semen utilized for artificial insemination?

• Fresh

• Cooled

• Frozen

What is the objective of utilizing semen extenders?

• provides optimal environment for the preservation of sperm viability » short-term

• provide pH buffer

• can preserve viability and motility in cooled sperm for up to 24 hrs

What is the reason to perform two or more inseminations during the estrus (changes the number of inseminations depending the species)?

• increase probability that there is enough sperm within the female’s oviduct at the proper time (ovulation)

• ensure successful fertilization

What is the correlation between site of insemination (distance to fertilization site) and insemination dose (volume/ sperm concentration)?

as deposition gets closer to the site of fertilization, the necessary volume for the insemination dose decrease

• closer to fertilization = less sperm needed

What might be the reasons to perform laparoscopic artificial insemination?

• for inseminating wild species

• handling could cause undo stress and affect pregnancy rates for untrained wild animals

• safety of the animals and the people working with them

What parameters affect the timing chosen and the number of times for artificial insemination?

• estrus length

• access to animals

• level of training for animal

• sperm availability

• semen type (fresh, cooled, or frozen)

• possible fertility issues

What is the objective of cooling semen?

• originally used b/c freezing was not an option

• maintenance of viability for longer periods to enable shipment

What is the relationship between temperature and storage time of semen?

inverse » as temperature decrease, storage time increases

What is the objective of utilizing cooling devices for storage/transportation of cooled semen?

to cool semen at a slow even rate in order to prevent cold shock

• maintain viability by preventing rapid temp change

Scenario: In horses, a standard insemination dose (at the time of insemination) is 500 million motile sperm. Cooled semen stored for 24 hours usually result in 50% viability (live sperm). What should be the initial sperm concentration in the insemination dose to account for the loses during the 24 hours storage time of cooled semen?

1 billion motile sperm

Can you collect semen utilizing an artificial vagina from any exotic animal? Explain why yes or no.

• Yes, but only if the exotic animals is habituated to human contact and well trained. Some exotics under human care that have been raised from birth by humans might have the potential to be trained well enough to utilize an artificial vagina for collection.

• wild and untrained exotics » NO

Which two parameters are important to consider when preparing an artificial vagina for semen collection? 

temperature and pressure

Is electroejaculation frequently utilized for semen collection in exotic/wild animals?

yes

What anatomical parts/organs of the male reproductive tract should be removed from a dead animal for post-mortem recovery of gametes? 

testes (total) and ductus deferens (as much as possible)

Which part of the epididymis contains more viable, motile and mature sperm and is useful for recovery of sperm post/mortem?

the tail of the epididymis

A solution frequently used for storage/transport of gonads for post-mortem recovery of gametes is? 

saline or phosphate buffered saline (PBS)

Mention 3 sperm processing methods

1. Swim Up technique

2. Density Gradient Technique (most used)

3. Microfluidic Devices » utilizing a membrane

Regarding sperm selection, what is the advantage of density gradient centrifugation compared to centrifugation with washing?

• more effectively separates higher quality sperm with minimal damage

  • better selection of progressively motile and morphologically sound sperm

What is the advantage of microfluidic devices over density gradient centrifugation? Why it has been lately preferred over other sperm processing methods in individuals with sensible sperm?

• because no centrifugation is required there is minimal mechanical stress on sperm

• better for individuals that produce poor quality or weak sperm

• reduced ROS

Name 3 reasons for performing embryo transfer 

1. can get more offspring from a single individual

2. Quicker genetic advancement

3. maintain work or production and use genetics simultaneously

4. mitigate fertility issues such as inability to carry pregnancies to term due to uterine problems

Name the 2 types of embryo collection/transfer 

1. surgical

2. non-surgical » embryo flushing

What type of embryo collection/transfer is usually utilized in exotic species? 

Surgical

T/F: When performing non-surgical embryo transfer (embryo flushing), the placement of the inflation balloon (from the foley catheter) changes between species.

true

When performing surgical embryo collection/transfer, usually which part of the female reproductive tract is exteriorized through the incision? 

uterine horns

Usually at which embryo developmental stage is the embryo recovered when performing embryo transfer (in most species)?

blastocyst

When performing embryo transfer of fresh/cooled embryos, is it important the estrous cycle synchrony between donor and recipient animal?

yes » donor and recipient estrous cycle must be synced

What is the objective of performing embryo cooling?

extend storage capacity and viability of oocytes for shipment between facilities

When performing embryo transfer of frozen embryos, is it important to consider the stage of the estrous cycle at the time of transfer? Why?

Yes:

• uterine condition must match that expected for the normal development of the embryo at the time of transfer

• progesterone levels must be correct

• recipient must be receptive (within receptivity period)

• recipient must be in correct stage of estrous for the sample being transferred

Name 3 reasons to perform in vitro fertilization (IVF)? 

1. controlled genetics

2. offspring can be produced from incompatible individuals

3. overcome age related reproductive issues

Name the 3 stages of in vitro production of embryos 

• In vitro maturation (IVM)

• In vitro fertilization (IVF)

• In vitro culture (IVC)

What is the objective of IVM?

to mature the oocyte so that it is in the right condition to be fertilized

What is the objective of IVF?

to get a zygote

What is the objective of IVC?

to reach the blastocyst stage

What are the two types of maturation that the oocyte has to reach before fertilization can happen?

1. nuclear maturation

2. cytoplasmic maturation

In most species (if not always), it is required to have a mature oocyte for fertilization (including techniques like IVF or ICSI). How can you determine the maturation status of an oocytes?

• cumulus cell expansion in an indirect indicator of oocyte maturation.

• appreciation of the presence of a polar body indicating that the oocyte has reached metaphase II

What is the objective to perform IVF using COCs from pre-pubertal females?

the speed up generational time in animals with long gestational periods and extended times to sexual maturation

ex: elephants = ~2 yr gestation plus 10-14 years to sexual maturity

Name 2 reasons to perform ICSI

1. resolve problems with sperm motility (fertility)

2. extremely efficient use of limited sperm from » highly endangered spcs or deceased individuals

What are the two types of ICSI? What does it use for injection?

• Regular ICSI » uses a regular injection pipette for sperm injection into oocyte

• Piezo ICSI- it uses a Piezo equipment for injection

What is the objective of performing embryo grading?

to select the embryos with the greatest probability for surviving successfully