Date post: | 26-Dec-2015 |
Category: |
Documents |
Upload: | chad-chase |
View: | 228 times |
Download: | 1 times |
Living vs. Nonliving The environment is made of both living and
nonliving things Biotic factors are all the living things that
directly or indirectly affect the environment Ex: organisms Abiotic factors are physical and chemical
factors that affect the ability of organisms to live and reproduce
Ex: intensity of light, temperature, water, soil and rock, minerals, gases, pH
If an abiotic factor is in short supply, it is a limiting factor
Limiting factors determine what types of organisms can exist in an environment
Ex: low levels of light may inhibit plant growth Ex: low (or high) temperatures may affect an
organism’s enzymes Ex: low oxygen levels in lakes affect how many
fish can live there
Ecology Ecology: the study of the interactions among
organisms and their interrelationships with the physical environment
Environment: an organism’s physical, chemical, and biological surroundings
All living things are dependent on each other and the nonliving environment
Ecological Organization Population: all the members of a species
inhabiting a given location at a specific time Community: all the interacting populations in an
area Ecosystem: the living community and the
physical environment functioning together as an interdependent, self-sufficient, and relatively stable system
Biosphere: the portion of Earth in which life exists
Ecosystems Ecosystems are self-sustaining if they: 1. have a constant source of energy 2. have a living system capable of turning this
energy into organic compounds 3. have mechanisms to cycle and recycle
materials between organisms and the environment
The Sun is Earth’s energy source, and plants incorporate solar energy into glucose
Nutrition Remember! Autotrophs make their own food,
and heterotrophs need to eat other organisms Saprophytes (decomposers): heterotrophs that
live on dead matterEx: fungi and bacteria
Herbivores: animals that eat only plants Carnivores: animals that eat other animals Omnivores: animals that eat both plants and
animals
Material Cycles The oxygen cycle involves photosynthesis and
cell respiration
Oxygen in air and water
Water
Cellular respiration and burning
Photosynthesis
The carbon cycle shows how carbon moves from the environment, into organisms, and back into the environment
CO2 in air and water and calcium
carbonate in soil
Organic compounds made in animals
Plants eaten by animals
Organic compounds made by plants
Respiration and decay
Burning, respiration,
decay
Photosynthesis
The water cycle is a very important limiting factor in any ecosystem
Evaporation: liquid water becomes water vapor Transpiration: evaporation of water from the
leaves of plants through stomata Condensation: water vapor becomes liquid water Precipitation: liquid or frozen water falls back to
the ground
Atmospheric Condensation (humidity, water vapor, fog, clouds)
Condensation
Water Table (ground water, oceans, lakes, ponds, rivers, wetlands)
Evaporation
Transpiration
Precipitation
Energy from the Sun
Cell respiration
and excretion
Rain, Snow, Sleet, Hail
The nitrogen cycle recycles the nitrogen necessary for the production of proteins
Nitrogen gas from the atmosphere is converted into nitrates by nitrogen-fixing bacteria
Plants use nitrates to make proteins Animals eat plants and convert plant proteins
into animal proteins Wastes and dead bodies are broken down by
decomposers, and ammonia is released Nitrifying bacteria convert ammonia into nitrates Denitrifying bacteria break down nitrogen
containing compounds and release nitrogen gas
Free nitrogen in air
Nitrates
Plant proteins
Animalproteins
Decomposers
Ammonia
Nitrogen-fixing bacteria
Animal and plant wastes
Denitrifying bacteria
Energy Flow The food chain shows how energy flows from
organism to organism Food chains start with producers (green plants)
that convert the Sun’s energy into organic compounds that can be used by other organisms
Consumers that feed directly on plants are primary consumers
Secondary consumers feed on other consumers Decomposers return chemicals to the
environment for reuse
Food webs are many interconnected food chains
Food webs are more accurate because organisms have evolved to eat more than one type of food
The direction of the arrows in a food chain or web shows the direction of energy flow
Pyramids A pyramid of energy shows the amount of usable
energy available at each feeding level The producers always have the most energy Only 10% of the energy available at one level
gets transferred to the next The other 90% is mostly lost as heat
The pyramid of biomass shows how many organisms can be supported at each level
The carrying capacity is how many members of a species can be supported by an ecosystem
There are always more producers than consumers
Symbiotic Relationships A symbiotic relationship is one in which
different organisms live in close association Commensalism: one organism is benefited and
the other is neither helped nor hurt (+, 0) Ex: barnacles on whales Mutualism: both organisms benefit (+,+) Ex: flowers and bees Parasitism: the parasite benefits and the host is
hurt (+,-) Ex: fleas on a dog
Biodiversity Biodiversity is the variety of different organisms
in an ecosystem Biodiversity increases the stability of the
ecosystem and increases the possibility of medical discoveries
Ex: many new medicines come from rainforest plants
Succession Succession: the replacement of one community
with another until a stable stage is reached The stable stage is a climax community Succession begins with pioneer organisms,
which are the first livings things in a given area Each new community modifies the environment
Makes it more unfavorable for themselves, but more favorable for the next community
Plant species are called flora Animal species are called fauna
Climax communities are self-perpetuating communities in which the populations remain stable and exist in balance with each other and the environment
A climax community will continue until a catastrophe or major change in the biotic or abiotic factors destroys it
Ex: forest fires, abandoned farms After the catastrophe, succession begins again
May end with a different climax community or the same one again
Habitats Habitat: particular area in the ecosystem where
a specific plant or animal lives Different species may need to use the same
resources in the habitat, so competition occurs The more similar the requirements, the more
intense the competition A niche is the role a species plays in its
environment Competition usually limits organisms to one
species per niche
Biomes A biome is the most common climax ecosystem
that will form in a geographic region Biomes can be terrestrial (land) or aquatic
(water)
Tundra The tundra is found in the northernmost regions
of North America, and Europe Very little precipitation (10 inches/year) Most of the ground remains permanently frozen
(permafrost) Trees cannot grow because the permafrost does
not allow for deep roots Most of the plants are mosses, grasses, and
lichens
The tundra has short, warm summers and long cold winters
Animals need to be adapted to the cold Ex: caribou, snowy owls, musk oxen
Taiga The taiga is found just south of the tundra in
North America, Europe, and Asia Receives more precipitation than the tundra The temperatures are warmer than the tundra,
so there is no permafrost The main type of tree is the conifer, which has
needles instead of leaves Winters are long and cold Animals may hibernate to avoid the winter
Temperate Deciduous Forest The deciduous forest is found in the eastern US,
Europe, and northeastern China This is the climax community of New York State Has cold winters and warm summers The main type of tree is the deciduous tree
Lose their broad leaves in the autumn Deciduous trees lose their leaves to prevent
water loss in the winter when water is limited
Soil in the forest is very richThe fallen leaves decompose and return nutrients to
the soil Examples of fauna: squirrels, deer
Tropical Rainforest The tropical rain forest is the most complex
biome on Earth All tropical rain forests are found near the
equator Receives 160 inches of rain each year
Rains nearly every day The abundant rain allows trees to reach over 200
feet tall
Grasslands Grassland biomes exist in both temperate and
tropical regions Receives about 30 inches of precipitation each
year and has strong winds There are no trees because there is not enough
rain Also experience occasional droughts
Grass thrives because its roots are very deep and reach underground water
Desert A desert biome experiences more evaporation
than precipitationWater evaporates faster than it can be replenished
Deserts receive less than 10 inches of precipitation each year
Rain is often violent and heavyMay receive all 10 yearly inches in one day
Deserts experience a wide range of temperatures Very hot during the day and very cold at night
Desert plants like cacti are succulentsHave thick, fleshy stems that store waterHave shallow, sideways roots that are able to quickly
absorb rainwaterSpines protect the plant from being eaten and reflect
sunlight away from the plant Trees in the desert are short because of the lack
of waterHave very deep roots to reach underground water
Desert plants are widely spaced to reduce competition for water
Lizards and snakes have thick scales to reduce water loss
Mammals like mice and kangaroo rats rest in underground burrows during the day to avoid the heat
Marine Biome The marine biomes are in the ocean They provide the most stable aquatic
environment Absorb and hold large amounts of solar heat and
stabilize the atmosphere Supply nutrients and dissolved salts Serve as a habitat to many diverse species