Download Notes: Unit 1 Ecosystems and Biomes

Notes: Unit 1
Ecosystems and Biomes
1. Environmental Science is the interdisciplinary field of study of human impact
on the world.
2. The term environment is used to describe the total surroundings of an
organism including other plants and animals that affect the organism during its
lifetime.
3. Ecology is the study of the interactions among all organisms and their
environment.
4. An Ecosystem is a community of living organisms and their environment, both
abiotic and biotic. Ecosystems may be small (e.g., log) or large (e.g., forest).
5. Similar organisms that can interbreed and produce fertile offspring is called a
Species.
7. Populations are groups of similar species living in the same area at the same
time.
8. A Community is an assembly of different populations that live together in a
defined area. A community includes producers, consumers, decomposers,
saprophytes, and detritovores.
9. Biomes are large areas made up of several ecosystems that share the same
climate and dominant plant communities.
10. Major Biomes include:
1.
2.
3.
4.
5.
6.
7.
11.
Tundra
Taiga
Temperate Forests
Grasslands
Chaparral
Deserts
Rainforests
Climate is the prevailing weather conditions in an area over time. Climate
plays a major role in determining the distribution of organisms on our biosphere.
The major components of climate are temperature. Precipitation, light and wind.
(Abiotic factors)
12. Temperature is mainly determined by Latitude (degrees North or south of the
equator) and Altitude. Temperature is also greatly influenced by proximate to
large bodies of water, such as oceans.
For every 1000 meter increase in altitude there is a temperature decrease of
10
o
C.
13. Windward sides of mountains are often wet due to orographic precipitation.
Leeward sides are dry (rainshadow). Deserts are often found on leeward sides of
mountain ranges.
14. Mountain sides with Southern exposures receive more light in northern
latitudes and therefore they often have different vegetative characteristics
then mountainsides with northern exposures. The reverse is true in the southern
hemisphere.
15. Limiting Factors are any conditions that limit a population’s growth. Factors
include the amount of food, water and shelter, the number of predators, and
disease.
16. Limiting factors can be Density dependent (competition, predation,
parasitism or disease) or density independent (weather, fire, clear cutting, etc)
17. An organism's niche is the conditions under which it can successful survive
and reproduce. These conditions include, temperature, amount of water, available
nutrients, pH range, etc. Each organism has a range of tolerance within which it
can live.
(ex. A certain temperature range, the amount of water it can tolerate, the
amount of saltwater in can live in, etc.)
18. Ecological Succession is a community change in which new populations of
organisms gradually replace existing ones.
19. Primary succession begins in an area where there was no existing community ,
such as a volcanic island. This rarely occurs.
20. Secondary succession occurs in an area where the existing community is only
partially destroyed. (e.g., light fires, wind damage, etc.). Very common.
21. Pioneer species are the first group of organisms to occupy an area undergoing
primary succession. Pioneer species tend to be short lived, reproduce rapidly and
have minimal requirements (e.g., mice, weeds, insects, etc.) Sometimes referred
to as r-selected.
22. Climax communities are stable, and well established and have high diversity.
Climax species are long lived, and have low reproductive rates (deer, cougar,
eagle, oak tree etc) . They are sometimes referred to as K-selective.
23. Adaptations in plants and animals occur as living conditions change over long
periods of time. The process of developing adaptations is called Natural
Selection .
24. Natural selection is driven by selection pressures such as availability of
water, sunlight, food, and predator prey relationships.
Aquatic Ecosystems/Biomes:
25. Two important aquatic ecosystems are Marine and freshwater.
26. Salt water (35/1000 ppt) covers 75 % of the Earth’s surface. This marine
environment is made up of several zones:
1. Intertidal zone (Littoral) – the area along coastlines between high and
low tides. Experiences extreme variations in temperature, moisture and
salinity.
2. Coastal zone (Neretic) – the region of water over the continental shelf.
Highly productive due to the rich supply of nutrients and warmer
temperatures.
3. Oceanic zone (Pelagic) – vast open ocean. Unproductive. Benthic
communities are sparse due to lack of sunlight.
27. The intertidal zone (Littoral) include three subzones: upper, middle and
lower. The upper is only submerged during spring tides and the lower exposed
only during spring tides.
28. Estuaries are shallow marine areas where salt water and fresh water mix.
The richest estuary in the world is the Chesapeake Bay.
29. Fresh water makes up less than 3 % of the Earth’s biosphere. Yet fresh
water is vital to nearly half of the Earth’s organisms.
30. The study of fresh water lakes and ponds is called Liminology.
31. Four important freshwater ecosystems include: rivers, lakes wetlands and
vennal pools.
32. Wetlands are among the richest and most valuable terrestrial biomes. They
serve as vital nurseries to a variety of wildlife, especially birds. Wetlands also
act to filter pollution, reduce siltation, and reduce flooding by acting as a natural
sponge to store water. Coastal wetlands protect the mainland from erosion
caused by storms and hurricanes.
33. A type of vital terrestrial wetland ecosystem for amphibians and some other
organisms are Vernal pools. These pools dry out during the summer and
therefore do not contain predator fish that would eat larval amphibians. Most
are small and over looked. [Vernal = spring]