Ch 5

Question 1

5 basic interaction types between species

Answer 1

1. Interspecific competition
2. Intraspecific
3. Parasitism
4. Mutualism
5. Commensalism

Question 2

2 categories of inter/intraspecific interaction

Answer 2

a. Competition

b. Predation

Question 3

Competition

Answer 3

• When 2 members compete for the same limited resources
• Competitive exclusion leads to resource partitioning- when species competing for similar resources
• Humans are dominant competitors

Question 4

Robert MacArthur’s research

Answer 4

studied birds that seemed to occupy the same biological niche- explored if there actually was overlap, of if they actually occupied and fed in different locations- e.g. time of day, specific parts of trees, etc

Question 5

Interspecific

Answer 5

Between species

Question 6

Intraspecific

Answer 6

Between different species

Question 7

Predation

Answer 7

• Predators are vital to most ecosystems to regulate prey
• They have adaptations that help them to better capture prey
• Similarly, prey have adaptations that help them to survive

Question 8

Aposematism

Answer 8

Describes a family of anti-predator adaptations where a warning signal is associated with unprofitability of a prey
Ex: Brightly colored to signal toxicity, specific calls
- Helps both predator and prey, because if it didn’t exist then both predator and prey would likely die
- Can lead to mimicry

Question 9

Batesian mimicry example

Answer 9

Yellow and black stripe of wasps: some harmless flies and beetles copy this visual pattern that makes predators stay away out of confusion that they are dangerous as well\

Question 10

Mullerian mimicry example

Answer 10

bees and wasps that have developed similar colors so that if a predator comes into contact with either one, it makes it less likely that the predator will attack the other species– broadening the advertisement of dangerous traits

Question 11

Coevolution example

Answer 11

darwin’s orchid- grows in a canopy of trees, develop long floral spurs with nectar producing cells so that animals with mouthparts longer than it so that it has to interact with the plant more. Alternatively, it is seen as more beneficial for insects to have longer mouthparts than the feeding structure of the plant, which leads to greatly exaggerated traits on both the insect and the plant

Question 12

Parasitism

Answer 12

Ticks:

• Climb up onto vegetation and leave their front two arms detached so that they can attach to anything that brushes against them
• They have anticoagulant properties injected from their saliva so they are more efficient at extracting blood, also give you the bacterial infection of lyme disease

Question 13

Masting

Answer 13

production of seed at long intervals, synchronously, by a population of plants
Red oaks mast every 5 years

Question 14

The acorn connection

Answer 14

\+acorns = +mice
\+mice = -gypsy moths
-gypsy moths = +acorns
\+acorns = +mice
\+mice = +deer
\+deer = +ticks
\+ticks = +lyme disease

Question 15

Effect of the acorn connection

Answer 15

Mast years lead to increases in mice, which prevent gypsy moth outbreaks, but lead to the increase of Lyme disease

Question 16

Are parasites helpful or harmful to communities?

Answer 16

Harmful on an individual level, but limit overabundance of competitive species- top-down control

Question 17

Mutualism

Answer 17

2 species behave in ways that benefit both by providing each with food, shelter, or some other resource– pollination, acacia

Question 18

Acacia-ant relationship

Answer 18

Mutualism- trees protect themselves from elephants by housing ants that swarm and climb onto elephants who try to eat them- effectively protects the trees
swollen stipular spines on the plant branches house ants and provide then with nutrition
Extra floral nectaries
Beltian bodies- protein and lipid-rich

Question 19

Ecological succession

Answer 19

normally gradual change in structure and species composition within a given species

Question 20

2 types of ecological succession

Answer 20

Primary- newly formed/ completely destroyed land- pioneer species are the first to develop
e.g. volcanoes
Secondary succession- destroyed/ wiped out, but not completely barren

Question 21

2 types of secondary succession

Answer 21

Allogenic- succession caused by an abiotic disturbance- fires, storms
Autogenic- succession caused by organisms within the system- leaf litter, spruce needle in alaska

Question 22

Why does ecological succession occur?

Answer 22

The environment changes, species must mirror those changes- species that adapt the best become the most prevalent at that time

Question 23

Why is ecological succession important?

Answer 23

Increases biodiversity due to the gradual progression of change of species- also leads to new ecosystem services

Question 24

Factors that influence ecological succession

Answer 24

Facilitation
Inhibition
Tolerance

Question 25

Facilitation

Answer 25

one set of species makes an area suitable for species with different niche requirements

Question 26

Inhibition

Answer 26

one species prevents another species from growing

Alilopathy- chem inhibition of one species to another

Question 27

Tolerance

Answer 27

plants in late stages of succession succeed bc they can better tolerate competition
Shade-tolerant trees

Question 28

Models of predictability of ecological succession

Answer 28

Clementsian view
Gleasonian view
Modern view

Question 29

Clementsian view

Answer 29

successional development occurs in the same way as organismal development– very predictable, the same species would be present- determined by climate- ultimately leads to an extremely stable climax

Question 30

Gleasonian view

Answer 30

species assemblages are simply the result of competitive inhibition through species and individual environmental preferences and tolerances- doesn’t lead towards a stable climax

Question 31

Modern view

Answer 31

show some predictability, strongly influenced by historical events, dynamic and influenced by disturbance, do not develop towards a stable climax (it isn’t a linear regression, but more like a cyclical process- no end goal, bc biological conditions are constantly changing)

Question 32

The kinds of dispersion

Answer 32

Clumped dispersion
Uniform dispersion
Random dispersion

Question 33

Clumped dispersion

Answer 33

individuals are more likely to be found closer to organisms of their same species
Resources tend to be clumped, not randomly distributed
Social interactions: reproduction, survival, hunting

Question 34

Uniform dispersion

Answer 34

In plants, distribution patterns that result from allelopathy- response to chemicals present in the environment
In animals, territories

Question 35

Random dispersion

Answer 35

organisms are not found to be close w other members of the species- very rare- resources are not distributed in the same area

Question 36

Limiting factors for pop growth

Answer 36

Competition
Predation
Human disturbances
Natural disasters
Parasitism and disease
Reproductive potential

Question 37

Reproductive potential formula

Answer 37

r represents slope of the line representing exponential growth
k represents carrying capacity of an ecosystem
r vs k selective species have different survival patterns