ecology unit 4

predation occurs in

different ways

carnivory

prey and predator are both animals

herbivory

predator is an animal that feeds on plants or algae

parasitism

predator (parasite) lives symbiotically (close to host) and consumes the host tissue

• usually keep host alive for steady source of energy

parasitoid

larva is inserted into host

• parasitic larva eats host from inside out

• must kill host to continue to aldulthood

predator prey interactions are categorized by

trophic levels

cycling and optimal foraging theory

trophic levels are organized as

(top) carnivores, herbivores, autotrophs (bottom)

animals/meat has ______ search time, ______ handling

high/difficult, easy

plants have ______ search time , _____ handling

low/easy, difficult

population cycles explain predator-prey interactions because

it displays density feedback loops

OFT explains predator-prey interactions because

showcases how a predator considers cost-benefit

• time needed to capture and energy < nutrition gained ?

most carnivores have a _____ diet

broad

most herbivores have a _____ diet

narrow

herbivores are considered

specialists

• Breaking down specific plants requires special features

carnivores are condsidered

generalists

• meat is hard to find so take what you can get

large herbivores specialize on

particular parts of the plant

• usually leaves bc are abundant and nutritious (apart from seeds)

nitrogen content in food is important because

fundamental for macromolecules (DNA, amino acids)

piscivore

carnivore that primarily eats fish

• ex. sharks

carnivores concentrate on whatever prey is most _____

abundant

• most efficient way (OFT)

3 hunting strategies

1. move around

2. sit and attack when prey is in range

3. setting traps

examples of traps

spidar web, tail that looks like bug

wave washing

hunting technique where a predator (ex. killer whale) locates prey on floating ice and swim underneath, creating a fake wash so the prey is knocked into water

adaptations to avoid being eaten

1. amour

2. size

3. speed

4. other

other adaptations include

being innutritious, being nasty (ex. skunk, emitting venomn) , automize, aposematic, mimic

automize

animal sheds its parts to escape predator

aposematic

animals use bright colours, odours, sounds or patterns to warn predators that they are toxic or distasteful

mimicry

organisms may mimic being aposematic to avoid being eaten. can also mimic enviroment

batesian mimicry

harmless species mimics a harmful species

• parasitic to the behaviour

mullarian mimicry

2 or more harmful species evolve to resemble each other

mutual benefit because predetor learns to avoid the one signal, can protect multiple species

ex. wasps and bees both have stingers and predetors avoid both

size is a

ecological variation that changes with life history

C.B Hufakker’s experiment proved why ______ exist

population cycles

prey don’t immediately go extinct because

• Environments are complex

• Predators have limited dispersal

• Predators switch prey (choose whichever is abundant)

• spatial refuges

• Evolutionary changes may make for better defences

trophic

feeding

non-trophic

competitive and facilitative (help each other or competitive)

categories of organism interactions

1. predation (+ / -)

2. competition (-/-)

3. positive (+/+)

4. amensilation (0/-)

facilitative /positive

at least one benefits and none are harmed

(+/+) or (+/0)

commensalism

+/0

• type of facilitative

amensalism

-/0

Parasitoids can be considered unusual

parasites or carnivores

• only eat one organism and kills it

most carnivores have _______ to help them capture prey

specialized features

ex. teeth, head size

ex. snake jaw can move wide enough to eat large prey

crypsis

form of mimicry that allows prey to conceal themself in form of camouflage

some prey _____ themselves differently when predators are around

disperse

• forage in less open areas

masting

method for plants to avoid being eaten. will produce alot of seeds some years and very little in others.

• avoid seed eating plants

plants may produce leaves at ________ to avoid predators

times predators are scarce

plant compensation

plant's response to damage where the removal of tissue (by herbivores) stimulates the plant to produce new tissue rapidly.Occurs when a plant fully replaces all lost tissue, resulting in zero net loss of total plant material despite being eaten.

when starfish (keystone species and apex) were removed, the blue muscles dominated over the

inferior species

the inferior species could flourish when the starfish were present because

the blue muscles (dominant competitor) were hunted by starfish. starfish are only interested in muscles bc of OFT

an indirect effect of predators is they can

affect transfer of nutrients from one ecosystem to another (ex. droppings)

marshes grew best when lightly grazed because

the NPP increased even with grazing due to extra nutrients from geese feces

top down control by herbivore

ex. cows grazed on seedlings before they could mature, making small shrubs more advantagous. when cows are removed , the seedlings are able to bloom.

generalists are harder to

get rid of

hare population cycles were driven by

land & air predators

effects of cortisol

increase of blood glucose, suppressed immune response, digestion, reproduction, growth

Why is the population recovery so slow even after predators die off?

organisms with high cortisol levels due to exposure to predators transmit cortisol to offspring

malaria is caused by

the parasite plasmodium species

bacteria help

• digest food

• synthesize vitamins

• maintain healthy gut microbiome

parasitism is (sign)

+/ -

enslaver parasites

parasites that alter host’s behaviour to complete the parasitic life cycle or infect next host

some parasites can cause disease

pathogen

macroparasite

large enough to see

microparasite

microscopic

parasites include herbivores

true

parasites usually have one or few hosts

true

• gets used to host body and specializes to feed on specific host or its relatives

50% of species on earth are parasitic

true

parasites are specialized to specific parts of the body

true

ectoparasite

live outside of host body

endoparasite

live on inside of host body

• in tissue or alimentary canal or cells

trichophyton rubrum

ectoparasite that causes athlete’s foot

lyme disease

caused by ticks (ectoparasite)

alimentary canal

tube running from mouth to anus. ectoparasites inhibit because food is available at both ends

alimentary parasites eat

ingested nutrients, don’t really eat host tissue

tissue and cell parasites can cause

disease as tissues are eaten and they reproduce

endoparasites in plants cause

wilting, rotting, death , disease

pros and cons of ectoparasite

pros:

• direct access to food

• safe from the external environment and natural predators

CONS

• hard to disperse

• vulnerable to host immune system

pros and cons of ectoparasite

pros

• easy to disperse

• safe from immune system

CONS

• harder to feed

• vulnerble to outside and natural enemies

natural enemies of parasites

predators, parasitoids, and parasites

scolex

suckers and hookers attatch to intenstinal wall

parasitic isopod

ectoparasite that enters host through gills and replaces its tongue

athropod like lice

ectoparasite

fleas, ticks and lie are ectoparasites

true

Dermatobia hominis

human botfly, macroscopic ectoparasite

population cycles can be examined by

documenting birth, death and dispersal rates

resources and predation drive population cycles

true

predation includes parasitism

true

competition

non-tophic interaction. species overlap in resources

trophic interaction

consumption of individual up the food chain

parasitoids are unusual

carnivores because focus on one individual to eat, parasites because they kill their host

plants are less nutritious than animals

true because they have less nitrogen

some carnivores show a preference for certain species

true

for example lynx will eat hares even tho they are less abundant than other species

seed eaters have an impact on

plants’ reproductive success

herbivores that feed on plant fluid impact

long-term growth. results are not immediate, but growth is stunted due to drained nutrients

Some predators capture prey by using

poison

Predators may draw in prey using

mimicry

some predators can change _____ to match prey

true (clinate)

some predetors can ______ prey venom

tolerate

when compensation is 100% , net loss of plant tissue is

0

compensation may occur when

1. loss of plant mass allows for deeper sun penetration (photosynthesis increases)

2. removal of buds

compensation can only occur if

resources (sun, water) are abundant. it cannot compensate in certain times due to resource scarcity

plants may have ____ to defend against predetors

spikes, hair, thorns

induced defence

defences mechanisms (ex. thorns) only appear after it has been grazed