Parasitism

Question 1

Case Study: Explain the life cycle of the gordian worm/hair worm

Answer 1

Gordian worm: Enslaver parasite
- Acts on insect host brain to make host drown itself
- When host drowns, returns the nematomorph to water
- Nematomorph mates in water
- Waits to occupy a new host’s body cavity incapacitating it and turning it into a zombie

Question 2

Consumes tissues or fluids of their host organisms typically infecting only one individual w/o killing it

Answer 2

Parasites

Question 3

A good parasite is one that _______ its host

Answer 3

does not kill its host

Question 4

Live in or on other organisms and can be mutualists or parasites

Answer 4

Symbionts

Question 5

T/F Paraistes typically feed on only 1 or a few host species, host species also only have 1 or few parasite species.

Answer 5

False, hosts have multiple parasite species

Question 6

Organism in a natural environment that does not harbor several species of parasites

Answer 6

Rarity

Question 7

Parasites and pathogens are ______ or atleast have a limited range of hosts

Answer 7

host-specific

Question 8

Parasite found externally

Answer 8

Ectoparasite

Question 9

Modified roots that plants use to penetrate tissues of host

Answer 9

Haustoria

Question 10

Plants that extract water and mineral nutrients from hosts but can photosynthesize alone

Answer 10

Hemiparasitic

Question 11

Parasite found internally

Answer 11

Endoparasite

Question 12

Open tube in animal bodies surrounded by tissues and runs from mouth to anus serving as an excellent habitat for parasites.

Answer 12

Alimentary canal

Question 13

T/F Endoparasites eat host tissues

Answer 13

False, they only rob the host of nutrients (eating the digested material in the alimentary canal)

Question 14

Structure with suckers used by tapeworm to attach to the host’s intestine

Answer 14

Scolex

Question 15

Advantages and Disadvantages of Ectoparasitism

Answer 15

Adv: Ease of dispersal, safety form immune system
Disadv: Vulnerability to natural enemies, difficult feeding, exposure to external environment

Question 16

Advantages and disadvantages of Endoparasitism

Answer 16

Adv: Ease of feeding, protected from external environment, safer from natural enemies
Disadv: Vulnerability to immune system, difficult dispersal

Question 17

Categories of parasites based on function rather than taxonomy or phylogenetics

Answer 17

Macroparasites & Microparasites

Question 18

Grow in their host but multiply with infective stages released to infect new hosts, longer generation times and can be counted and infections are chronic

Answer 18

Macroparasites

Question 19

Reproduce within host often within host’s cells. Too small to be seen with short lifespans and can lead to development of immunity. Infections are often transient.

Answer 19

Microparasites

Question 20

Live in close association with their hosts

Answer 20

Symbionts

Question 21

Interaction where 1 organism harms another without any cost or benefit received

Answer 21

Ammensalism

Question 22

Interaction where 1 organism benefits while the other is unaffected

Answer 22

Commensalism

Question 23

Interaction where both species involved benefit

Answer 23

Mutualism

Question 24

Non-mutual symbiotic relationship where 1 benefits while the other is actively harmed

Answer 24

Parasitism

Question 25

Symbionts that protect their hosts from parasitic symbionts

Answer 25

Mutualistic defensive symbionts

Question 26

Differentiate simple and complex life cycle

Answer 26

Simple basically means that dispersal is very quick, complex means there are multiple stages in the life of the organism

Question 27

Transmission between individuals that are not linked by parent-child relationship

Answer 27

Horizontal transmission

Question 28

Transmission from mother to offspring

Answer 28

Vertical Transmission

Question 29

Parasites that cause disease manifesting as pain, dysfunction, or death

Answer 29

Pathogens

Question 30

Parasites taht rely on other organisms to raise their young

Answer 30

Brood Parasites

Question 31

Parasites that steal food from competitors.

Answer 31

Kleptoparasites

Question 32

This includes the immunesystem, biochemical defense, and mutualistic defensive symbionts which all protect hosts against parasites

Answer 32

Host adaptation defenses

Question 33

Recognize microparasites from previous exposures

Answer 33

Memory cells

Question 34

When cells are damaged by microparasite infection, it releases molecules that stimulates production of antimicrobial compounds called:

Answer 34

Phytoalexins

Question 35

Removes iron from blood serum in vertebrate hosts to prevent bacterial and fungal parasites from getting it

Answer 35

Transferrin

Question 36

Chemical weapons used by plants against parasites

Answer 36

Secondary compounds

Question 37

Increased survival of aphid genotypes exposed to pathogenic fungi is an example of?

Answer 37

Defensive symbionts

Question 38

Adaptations that circumvent host defense

Answer 38

Parasite counter defenses

Question 39

Process allowing parasites to elude action of antibodies

Answer 39

Molecular Mimicry

Question 40

Process of covering parasites or parasite eggs with capsules that kill them to render them harmless

Answer 40

Encapsulation

Question 41

Blood cells that can form multicellular capsules around large objects such as nematodes

Answer 41

Lamellocytes

Question 42

Plasmodium is a protozoan causing malaria and is an example of counterdefenses involving hundreds of genes, explain its complex lifecycle in its two hosts

Answer 42

1.Sporoziote Stage - Present in Saliva of infected mosquito and is injected when they bite humans 2. Merozoites - Sporozoites migrate to liver and divide to form merozoites that penetrate RBC multiplying rapidly causing lysis, some become gamete-producing cells 3. Mosquito bites infected human ingesting gamete producing cells that form gametes uniting to form a zygote 4. Zygote produces thousands of new sporozoites that migrate to salivary gland

Question 43

Occurs when populations of 2 interacting species evolve together in response to selection pressure imposed by the other

Answer 43

Coevolution

Question 44

Animals or plants of related species or populations occurring within the same geographical areas

Answer 44

Sympatric

Question 45

Animals or plants of related species or populations occurring in separate, non-overlapping geographic areas

Answer 45

Allopatric

Question 46

Parasites are better at infecting hosts that they are sympatric or allopatric with?

Answer 46

Sympatric

Question 47

Occurs when plant defense systems include a specific response that makes particular plant genotypes resistant to particular parasite genotypes

Answer 47

Gene-for-gene interactions

Question 48

T/F Due to common host genotypes being targeted by parasites, there is also a decrease in the rare genotypes

Answer 48

False, since common host genotypes are attacked, rare genotypes tend to be more fit in the environment leading to proliferation

Question 49

Model used in epidemiology that subdivides the population into compartments

Answer 49

SIR Model

Question 50

Density of susceptible hosts that when exceeded, disease will spread

Answer 50

Threshold Density

Question 51

How to calculate threshold density

Answer 51

𝑆_𝑇 =𝑚/β where: 𝑆_𝑇 = Threshold Density m=combined death and recovery rate β = transmission coefficient

Question 52

What are the 7 different macroevolution trajectories?

Answer 52

Cospeciation - Parasite evolves along with host Host switch - Parasite switches host Duplication - Parasite speciates, host stays the same Failure to speciate - Parasite stays the same, host evolves Missing the boat - Only host speciates, no parasite on new host sp Extinction - Parasite dies Coexistence - Stable with each other, no change