Chapter 14 - Interactions in Ecosystems

Question 1

What is a habitat? 14.1

Answer 1

Where an organism lives

Include abiotic and biotic factors

Question 2

What is an ecological niche? 14.1

Answer 2

It is composed of all of the physical, chemical, and biological factors that a species needs to survive, stay healthy, and reproduce; its role.
Includes:
Food: what kind, how it is obtained, etc…
Abiotic conditions: temperature, amount of water needed, etc…
Behavior: when it is active during the day, where and when it reproduces, etc…

Question 3

What is the difference between a habitat and a niche? 14.1

Answer 3

A habitat is where a species lives and a niche is how it lives within its habitat.

Question 4

What happens in mutualism? 14.2

Answer 4

Both species benefit (+/+)

Question 5

What happens in commensalism? 14.2

Answer 5

One member benefits, the other is not helped nor harmed (+/0)

Question 6

What happens in parasitism? 14.2

Answer 6

One organism lives off the other organism while harming it (+/-)

Question 7

What is ectoparasite vs. endoparasite? 14.2

Answer 7

Ectoparasite—lives outside the host

Endoparasite—lives inside the host

Question 8

What is symbiosis and what are the three types? 14.2

Answer 8

Close ecological relationship between two or more organisms of different species that live in direct contact with one another
Mutualism
Commensalism
Parasitism

Question 9

What is competition? 14.2

Answer 9

When 2 organisms fight for the same limited resources

Question 10

What are the two types of competition? 14.2

Answer 10

Interspecific competition—between two different species

Intraspecific competition—between members of the same species

Question 11

What is predation? 14.2

Answer 11

Process in which one organism captures and feeds upon another organism

Question 12

What are the 3 important features of population? 14.3

Answer 12

1. Population size—the number of individuals in a population
2. Population density—the number of individuals that live in a given area
3. Dispersion—the way individuals of a population are arranged in an area

Question 13

How do you calculate population density? 14.3

Answer 13

# of individuals/  =  population density
Area (units2)

Question 14

What are the 3 patterns of dispersion? 14.3

Answer 14

Random—ex. Solitary animals such as sloths
Even or Uniform—occur at regular intervals—ex. Nesting sites of gannet on page 437
Clumped—individuals are bunched together in clusters—ex. Schools of fish

Question 15

What is a survivorship curve?

How many are there? 14.3

Answer 15

Diagram that shows the number of surviving members over time from a measured set of births
3

Question 16

What happens in type 1 survivorship curve? 14.3

Answer 16

Type I—low level of infant mortality and a population that will mostly survive to old age
common in large mammals (and humans); characterized by infant care to ensure infant survival

Question 17

What happens in type 2 survivorship curve? 14.3

Answer 17

Type II—survivorship rate is roughly equal at all ages of an organism’s life
common in birds, small mammals, and some reptiles; susceptible to predation and disease

Question 18

What happens in type 3 survivorship curve? 14.3

Answer 18

Type III—very high birth rate but very high infant mortality rate, few move on to adulthood
invertebrates, fish, amphibians, and plants; many offspring die from predation

Question 19

What are 4 factors that affect population size? 14.4

Answer 19

Immigration—movement of individuals into a population from another population
Births—increase the number of individuals in a population
Emigration—movement of individuals out of a population and into another population
Deaths—decrease the number of individuals in a population

Question 20

What is an exponential growth and what happens in it? 14.4

Answer 20

Exponential Growth Curve (J-shaped curve)—a curve in which the rate of population growth stays the same, as a result the population size increases steadily
Resources (food and space) are abundant
J-curve is a population that will grow if all individuals survive and reproduce at maximum capacity with no limiting factors

Question 21

What are the 2 phases of exponential growth? 14.4

Answer 21

Two phases:
Lag – little or no increase
Exponential – very rapid increase - # of individuals doubles in time intervals

Question 22

What is a logistic growth and what happens in it? 14.4

Answer 22

Logistic Model (S curve) –a population model where exponential growth is limited by depleting resources causing a population to reach carrying capacity; relative stability that occurs after Lag and Exponential Phase

Question 23

What is the carrying capacity? 14.4

Answer 23

Carrying capacity—the maximum number of individuals an environment can support; where birth rate equals the death rate
In nature, carrying capacity can change when the environment changes

Question 24

What are the two types of limiting factors? 14.4

Answer 24

Density-independent

Density-dependent

Question 25

What is density-dependent limiting factor? 14.4

Answer 25

Density-dependent limiting factor—limited resources whose rates of depletion depend on the density of the population using them
Ex. Competition, predation, parasitism and disease

Question 26

What is density-independent limiting factor? 14.4

Answer 26

Density-independent factor—environmental conditions that limit population growth regardless of population size
Ex. Weather, natural disasters, human activity

Question 27

What is a population crash? 14.4

Answer 27

A dramatic decline in the size of a population over a short period of time

Question 28

What are R-Strategists?

Answer 28

R-strategists
Ex: Bacteria, Cockroaches, mosquitoes, most insects, some plants
Grow exponentially when environmental conditions allow them to reproduce
Temporarily large populations
Short life span
Reproduce early in life
Produce many offspring during each time of reproduction
Small offspring with little or no parental care
When environmental conditions worsen, population size drops drastically
-TYPE 3

Question 29

What are K-Strategists?

Answer 29

Ex. Gorillas, whales, humans, elephants, Redwood trees, tigers
Populations grow slowly and population density is usually near the carrying capacity of the environment
Long life span
Few young with a slow maturing process
Reproduction late in life
Parents often provide extensive care for their young
Many endangered species are these
-TYPE 1

Question 30

What is ecological succession? 14.5

Answer 30

Sequence of biotic changes that regenerate a damaged community or create a community in a previously uninhabited area

Question 31

What are the two types of ecological succession? 14.5

Answer 31

Primary

Secondary

Question 32

What is primary succession and what are some examples? 14.5

Answer 32

Primary succession (Figure 14.16)—succession that occurs in an uninhabited area
Examples
new lava or rock from a volcano, makes a new island or a new landscape
sand bar that arises from shifting sands in the ocean
exposure of rock surfaces by a land slide or glacial retreat
meteor makes a depression that fills with rainwater or fresh water from underground streams
sand dunes can be great for observing primary succession

Rock surface  Lichens  Decomposers  Mosses  Ferns, shrubs  Pines  Hardwoods

Ex. Lichen on rock starts to die and make a foundation of soil for things like moss, then grass and ferns, bushes, trees, forest

Question 33

What is secondary succession and what are some examples? 14.5

Answer 33

Secondary succession (Figure 14.17)—the sequence of community changes that takes place after a community is disrupted by natural disasters or human actions
Ex. Fire, natural disasters, human activity, etc…
Secondary succession is continually happening after small disturbances which kick start succession.

Question 34

What are pioneer species? 14.5

Answer 34

First species in an area; usually lichen or moss which breakdown rock

Question 35

Which succession occurs more often presently? 14.5

Answer 35

Secondary

Question 36

Which type of succession takes a longer time to complete? 14.5

Answer 36

Primary

Question 37

What’s the difference between emigration and immigration? 14.4

Answer 37

Immigration is the movement of individuals into a population from another while emigration is the movement of individuals out of a population into another