Biology - Chapter 14: Ecology

Question 1

Ecological community

Answer 1

-all populations in a given area

Question 2

Ecosystem

Answer 2

-all organisms in an ecological community + abiotic factors interacting within it

Question 3

Biosphere

Answer 3

-all ecosystems on Earth, their interactions with each other and the litho, geo, hydrosphere

Question 4

Density dependent factors

Answer 4

• depend on population density

- e.g. disease, resource competition

Question 5

Density independent factors

Answer 5

• do not depend on population density

- e.g. climate, weather

Question 6

Niche

Answer 6

• biotic and abiotic resources an organism uses
• Realized niche: where it truly lives
• Fundamental niche: full range of environmental conditions where it could survive

Question 7

Gause’s Law

Answer 7

• competitive exclusion principle
• Two species cannot occupy the same niche and maintain population levels, one will outcompete the other
• Resources partitioning allows species to coexist

Question 8

Intraspecific competition

Answer 8

-occurs between members of the same species

Question 9

Exploitation competition

Answer 9

• indirect competition

- occurs when resources are depleted, affecting other populations

Question 10

Apparent competition

Answer 10

-occurs when one predator preys on two species

Question 11

Mutualism

Answer 11

+/+

Question 12

Coommensalism

Answer 12

+/0

Question 13

Parasitism

Answer 13

+/-

Question 14

Trophic level

Answer 14

• organism’s position within a food chain or food web
• only 10% of energy stored in a trophic level is converted to organic tissue
• primary producer < primary consumer < secondary consumer < tertiary consumer < apex predator

Question 15

Saprophytes

Answer 15

• plants, fungi, microorganisms

- decomposers that consume dead or decaying organic material and work with scavengers in organic recycling

Question 16

Detritivores

Answer 16

• worms, slugs

- consume detritus, exposing more organic material for decomposers

Question 17

K-selected species

Answer 17

• humans, large mammals
• type I survivorship curve
• long gestation period
• few large offspring
• long time to mature
• significant parental investment
• high survival to reproductive age

Question 18

R-selected species

Answer 18

• bacteria, insects, species w/ free swimming larvae
• type III survivorship curve
• abundant
• small offspring
• mature quickly
• no parental investment
• many do not survive to reproductivee age

Question 19

Type II survivorship curve

Answer 19

• e.g. hydra, some birds & small mammals, lizards

- Survival probability is constant regardless of age

Question 20

Ecological succession

Answer 20

• Predictable process where an ecological community develops and changes over time
• occurs in a new habitat or after a disturbance

Question 21

Primary succession

Answer 21

• occurs after a large disturbance in an area that has never supported life before
• begins with pioneer species
• eventually, a climax community results

Question 22

Secondary succession

Answer 22

-occurs on terrain that has supported life previously, and has had destruction following a disturbance

Question 23

Order of Organism Colonization

Answer 23

pioneer species -> thin soil -> vascular plants -> larger plants -> animals

Question 24

Keystone species

Answer 24

-Maintains ecological balance despite low abundance

Question 25

Aquatic biomes

Answer 25

• Largest of earth’s biome (75% of earth’s surface)
• Photosynthetic algae contribute most of Earth’s atmospheric O2
• Divided into freshwater biomes (3%) and salt water biomes (97%)

Question 26

Layers of the ocean

Answer 26

1) Euphotic zone: closest to surface, sunlight (littoral zone is the area of the euphotic zone where sunlight penetrates all the way to the ocean floor)
2) Disphotic zone: semi-irradiated (not sufficient for plants), bioluminescent species produce light here
3) Aphotic zone: bottom, no light or photosynthetic species