Lesson 13 Ecology successions Ecosystems

Question 1

Glaciation, fire, flood, earthquake and human impact are examples of…

Answer 1

community level disturbances

Question 2

After retreat of a glacier, stages of primary succession are:

Answer 2

-bare rock-pioneers such as bacteria, fungi, algae, and lichens -short grasses-weeds and short shrubs -short trees-willows and alders

Question 3

When lichens build soil on bare rock, enabling the colonization of short grasses is an example of…

Answer 3

facilitative replacement

Question 4

What succession____ is the change in community structure over time-consecutive changes?

Answer 4

ecological succession.

Question 5

Causes of ecological succession:

Answer 5

disturbances, fire, flood, glaciation, human activity are causes of ecological succession.

Question 6

What changes/improves conditions of the environment allowing for another species to colonize?

Answer 6

facilitative replacement i.e. lichen

Lichen, For example, an organism that increases the acidity of soil improves conditions for conifers.

Question 7

___ begins in an area that completely lacks community structure.

Answer 7

primary succession.

it can result from a catastrophic event like glaciation, earthquake, or forest fire. after a glacier retreats, the exposed rock is completely barren of life.

Successional stages on the rock include pioneer organisms, short grasses and short trees.

Question 8

What are the first to colonize the rock after primary succession?

Answer 8

bacteria, fungi, algae, lichens are the first to colonize the rock after primary sucession. Especially the lichen, builds soil on the rock.

Hundreds of years later, enough soil is present to permit the growth of shortgrasses.

The growth of short trees, such as willows and alders, represents the third stage of the ecological succession.

Lichen: consists of fungus and Alga. symbiotic association of algal and fungus.

Question 9

What builds soil on the rock for hundreds of year to form soil and permit the growth of shortgrasses?

Answer 9

lichen, a pioneer organism

Question 10

Growth of ____ represents the 3rd stage of the ecological succession?

Answer 10

short trees, willows and alders are the 3rd stage of the ecological succession.

Question 11

Lichen consists of:

Answer 11

fungus and algae- symbiotic association of algal and fungas.

Question 12

Lichen is a symbiotic association of millions of photosynthetic algae cells enmeshed in __?

Answer 12

fungal hyphae. The fungi absorb water, minerals, algae fix carbon through photosynthesis.

The lichen attaches itself to a rock via the fungal hyphae.

Question 13

Lichen dries out and releases ______ that break down the rock to form soil.

Answer 13

Lichen realeases acids

that break down the rock to form soil.

Question 14

Short grasses leads to short trees.

Willows increase the ____ content of the soil.

Answer 14

nitrogen content is increased by willows. the willows increase the nitrogen content of the soil, favoring the growth of alder trees. The graph shows a spike in the number of alder trees (shaded red) when soil conditions are favorable.

After nitrogen is fixed, the soil becomes more suitable for conifers; this is an example of facilitative replacement.

Alder tree is a nitrogen fixer. Bacteria that takes nitrogen out of the air and makes available to alder tree.

Question 15

What occurs after a disturbance that removes all organisms and organic matter from a habitat?

Answer 15

Primary succession

Question 16

What occurs after a disturbance that only removes a part of the community?

Answer 16

Secondary sucession- it leaves behind intact soil.

Question 17

In secondary succession, an existing community is disrupted and leaves the ______ instact.

Answer 17

soil.

American settlers eliminated nearly all of the country’s virgin stands of deciduous forest.

Question 18

Examples of secondary succession on land include:

Answer 18

fields to small shrubs to weed trees to forests

Question 19

Examples of secondary succession in lakes:

Answer 19

lakes to marshes to wet fields to shrubs to trees to forests.

Question 20

Each stage _____ the preexiting vegetation.

Answer 20

inhibits.

field> colonizes > shrubs (shade the grass) > Weed tress (poplars, tall shrubs) which shades the shrubs, and some shrubs die.

• establish a deciduous forest.

Question 21

Examples for secondary succession are:

Answer 21

old field growth or after a fire

Question 22

Oligotrophic lake is

A. nutrient poor with little phytoplankton

B. nutrient rich with much phytoplankton

Answer 22

A. nutrient poor with little phytoplankton

oligotrophic lake is nutrient poor, clear, deep lake with little phtoplankton.

Over time, oligotrophic lakes fill in with sediments and nutrients forming eutrophic lakes.

When it becomes shallow, standing vegetation will grow. Progressing to now classified as a marsh or swamp which give rise to wet fields, fields to forest etc.

Question 23

___ is the number of species in a community

Answer 23

Species diversity

Species in a community are interdependent on one another. The extinction of a particular species will affect the other species that rely on it as a prey item.

Question 24

Community is…

Answer 24

all of the organisms that live in a certain area and interact with each other.

Question 25

Food chain (web) consists of \_\_\_\_,\_\_\_\_,\_\_\_\_\_.

Answer 25

Predators, Primary consumers, Primary producers. If species B becomes extinct (as portrayed by the black box), predators such as species E are affected, and will have to compensate by feeding more intensely on A, C, and D. The populations of A, C, and D **may be detrimentally affected,** as well as the autotrophic plants that they consume. The example shows that the **loss of one species can affect the entire food web of producers, consumers, and predators.** A loss in species diversity, the number of species in a community, can *affect the stability of a community.* The food web shown shows that, **with the exception of autotrophs**, *organisms rely on other organisms to obtain food.*

Question 26

The number of species in a community is....

Answer 26

species diversity

Question 27

What are organisms that form the base of a food chain, usually photoautotrophs?

Answer 27

Primary producers

Question 28

What is caused by humans and our role as consumers, ecological niche is as consumer?

Answer 28

**Mass extinction**, An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms.

Question 29

What two ecosystems are particularly affected?

Answer 29

**Tropical rainforests** and **coral reefs**. The tropical rainforests contain the ***highest species diversity*** of any ecosystem on Earth.

Question 30

Tropical rainforest contribute to species diversity by:

Answer 30

1. climate 2. nutrient availability 3. diversity of species leads to further diversification \*a survey of 19 panamanian rainforest trees yielded 1200 beetle species, 80% of which were previously unknown.

Question 31

Some trees in the rainforest are unable to sexually reproduce, they can seed without sexual reproduction using a process called \_\_\_\_\_\_.

Answer 31

apomixis

Question 32

Two primary causes of destruction are the use of _________________ for construction and eating _____________ beef....

Answer 32

**tropical wood** for construction **eating south american beef** from cattle raised in the tropics. Cows are raised on rainforest land. Decisions about ending tropical rainforest destruction should protect the indigenous people’s right to a fair standard of living. How are we affecting the tropical rainforest? Because as consumers we may unknowingly destroy the rainforest.

Question 33

FIVE Major causes of destruction/threats to coral reefs:

Answer 33

1-Global warming -CO2 emissions 2-Runoff 3-Sedimentation 4-Collection of coral 5-cyanide fishing Approximately 24% of all marine species live on coral reefs. Over 1 million ocean species of life on a reef. 27% of the reefs have been effectively lost.

Question 34

What is the mutualistic symbionts in the dermal tissue of many corals?

Answer 34

Zooxanthellae ## Footnote ***An increase in water temperature of only one or two degrees causes coral bleaching***, an event where the coral expels its zooxanthellae. Global warming may be raising the ocean temperature and contributing to coral bleaching. \*El Nino of 1998 caused bleaching event that destroyed 16% of all coral reefs over a 9 month period. Lost 27% of total.

Question 35

A _____ is a collection of organisms of the same species.

Answer 35

Population In biology, a population is all the organisms of the same group or species, which live in a particular geographical area, and have the capability of interbreeding.

Question 36

What is the most comprehensive level of organization an ecologize can study?

Answer 36

Ecosystem- There are two major ecosystem level processes: A flow of energy and a cycle of materia. ## Footnote it includes the community encompassing all of its biotic and abiotic factors. \*organisms and their environment.

Question 37

What are the two major ecosystem level processes?

Answer 37

1. Flow of energy 2. cycle of material Some living things (**primary producers**) have organized systems that harness light energy from the sun. Other living things (**consumers**) feed on these organisms or other consumers. Because of entropy, *energy transfer through the food chain is inefficient*. In ecological systems, energy does not cycle; it is constantly dissipated and lost as heat energy.

Question 38

What obtains energy from non-living organic material?

Answer 38

detritivore an animal which feeds on dead organic material, especially plant detritus.

Question 39

Is the amount of materials on the planet finite?

Answer 39

Yes. These materials are constantly being recycled by organisms. Must be reused. In contrast to the one-way flow of **energy**. Energy flows from the sun through various trophic levels beginning with primary producers.

Question 40

\_\_\_\_ what inputs? are **autotrophs**, capable of obtaining organic food molecules without eating other organisms. Plants use the energy from the sun to convert carbon dioxide to sugars.

Answer 40

Primary producers are INPUT Primary Consumers Feed on primary producers - Herbivores.

Question 41

What shows the transfer of food energy from one trophic level to the next starting with primary producer.

Answer 41

Food chain - not that simple to show the flow.. reality is a food web. Energy flows by eating. There are levels starting from primary producer that use solar energy to synthesize sugar. a mouse is a primary consumer an owl is the secondary consumer, feeding on the mouse.