The Living World: Ecosystems & Biodiversity

Question 1

Ecosystems

Answer 1

A system of interconnected elements: a community of living organisms and its environment that includes biotic (living) and abiotic (nonliving) components interacting

Question 2

Evolution

Answer 2

A change in a population’s genetic composition over time
*Biodiversity
A phylogenetic tree models evolution

Question 3

Natural Selection

Answer 3

The beneficial characteristics are passed down to the next generation while unfavorable characteristics become less common
A cause that reduces reproductive success in a portion of the population is a selective pressure which drives natural selection

Question 4

Microevolution vs. Macroevolution

Answer 4

Microevolution is when a population displays small-scale changes over a relatively short period of time
Macroevolution is when a populations experiences large-scale patterns of evolution over a long period of time

Question 5

Niche

Answer 5

A species’ niche is described as the total sum of a species’ use of the biotic and abiotic resources in its environment.

Question 6

Specialist vs. Generalists

Answer 6

A specialist is one that has a narrow niche and can only live in a certain habitat
A generalist is one that has a broad niche, highly adaptable, and can live in varied habitats

Question 7

Intraspecific Competition vs. Interspecific Competition

Answer 7

Intraspecific competition: the two individuals competing are of the same species
Interspecific competition: the two individuals are of different species

Question 8

Resource Partioning

Answer 8

Two different species use slightly different parts of the habitat, but rely on the same resource

Question 9

XXX

Answer 9

Competitive exclusion: when two different species compete and the better adapted species wins
Gause’s Principle: no two species can occupy the same niche at the same time and that the species that is less fit will relocate, die our or occupy a smaller niche
A realized niche: when a species occupies a smaller niche than it would in the absence of competition

Question 10

Resource Partitioning

Answer 10

Different species use slightly different parts of the habitat but rely on the same resource

Question 11

Symbiotic Relationships & The Their Types

Answer 11

Symbiotic relationships: close, prolonged associations between two or more different organisms of different species that may, but do not necessarily, benefit each member
Mutualism: both species benefit
Commensalism: one organism benefits while the other is neither helped nor hurt
Parasitism: one species is harmed and the other benefits

Question 12

Aquatic Life Zones

Answer 12

Categorized by the salinity of their water

Question 13

Freshwater Biomes Layers

Answer 13

Littoral zone: shallow water at shoreline, plants, and animals reside receive abundant sunlight
Limnetic zone: the surface of open water, organisms in this region are short-lived and rely on sunlight
Profundal zone: water that is too deep for sunlight to penetrate, no animals and plants, only organisms that are adapted to little light, colder temperatures, and less oxygen
Benthic zone: surface and sub-surface layers of the river, low temp and low oxygen. inhabited by organisms that live on, in or below sediment surface (bacteria and fungi)

Question 14

Estuary

Answer 14

A site where the arm of the sea extends inland to meet the mouth of a river. They are rich in many different types of plant and animal species due to the high concentration of nutrients and sediments.
The water is usually shallow, and fairly warm and the species receive significant sunlight.
*saltwater marshes, mangrove forests, and river mouths
Wetlands: areas along shores of fresh bodies of water. Types include marshes, swamps, bogs, and prairie.
Mangrove swamps: coastal wetlands, tropical regions, trees, shrubs, and plants
*diverse due to the swamps being replenished with nutrients transported by freshwater runoff from the land

Question 15

Ocean Zones

Answer 15

Coastal zones: consist of the ocean water closest to land. Life thrives here due to abundant sunlight and oxygen, the proximity of the sediment surface allows for niches.
Euphotic zone: upper layers of water, warmest region of ocean water, highest levels of dissolved oxygen.
Bathyal zone: middle region; colder, darker, and does not receive enough light to support photosynthesis. lack of nutrients.
Abyssal zone: deepest region of the ocean, extremely cold temperatures, and low levels of dissolved oxygen but high levels of nutrients because of decaying plant and animal matter that sinks down from above. decomposers.

Question 16

Upwellings

Answer 16

Provide a new nutrient supply for the growth of living organisms in the photic regions

Question 17

Cycles in Nature

Answer 17

Reservoir: a place where a large quantity of a nutrients sits for a long period of time
ex: water cycle - ocean
Exchange pool: a site where a nutrient sits for only a short period of time
ex: water cycle - cloud
Residency time: the amount of time a nutrient spends in a reservoir or exchange pool
The energy that drives biogeochemical cycles:
Sun & heat energy from the mantle and core of the earth
Law of Conservation of Matter: matter cannot be created nor destroyed

Question 18

Net Primary Productivity

Answer 18

The amount of energy that plants pass on to the community of herbivores in an ecosystem

Question 19

Gross Primary Productivity

Answer 19

The amount of sugar that the plants produce in photosynthesis

Question 20

Detritivores

Answer 20

The organisms derive energy from consuming nonliving organic matter such as dead animals or fallen leaves
ex. earthworms and crabs

Question 21

Decomposers

Answer 21

Organisms that consume dead plant and animal material

This process returns nutrients to the environment

Question 22

10% Rule

Answer 22

Only 10% of the energy is transferred from one level to the next, the other 90% is lost as heat or used for respiration, digestion, and running from predators.

The producers have the most energy in an ecosystem

Question 23

Bottleneck

Answer 23

When a large proportion of a population is lost, a bottleneck occurs which reduces genetic diversity within the species

Question 24

Theory of Island Biogeography

Answer 24

The number of species found on an island or isolated area is determined by immigration & extinction.
Immigration: invasive generalist species may outcompete native specialists and threaten their long time survival

Question 25

Ecosystem Services

Answer 25

Provisioning Services: providing humans with water, food, medicine, raw materials, energy, and ornaments
Regulating Services: waste decomposition and detoxification, purification of water and air, pest and disease control, and regulation of prey populations through predation and carbon sequestration
Cultural Services: use of nature for science and education, therapeutic and recreational uses, and spiritual and cultural uses
Supporting Services: primary production, nutrient recycling, soil formation, and pollination (one that makes other services possible)

Question 26

Keystone Species

Answer 26

A species whose very presence contributes to an ecosystem’s diversity and whose extinction would consequently lead to the extinction of other forms of life

Question 27

Indicator Species

Answer 27

Species that are used as a standard to evaluate the health of an ecosystem
They are more sensitive to biological changes within their ecosystem than other species so they can be used as an early warning to detect changes to a community

Question 28

Primary Succession vs. Secondary Succession

Answer 28

Primary Succession: Ecological succession begins in a virtually lifeless area
Secondary Succession: Ecological succession that takes place where an existing community has been cleared by disturbance events but the soil has been left intact.
The organisms in the first stages of succession are known as pioneer species, have wide ranges of environmental tolerance