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Introduction to Ecology, Ecosystems & Interactions
Transcript of Introduction to Ecology, Ecosystems & Interactions
Introduction to Ecology, Ecosystems & Interactions
•The science used to study how organisms interact with each other and their environment.
1.Abiotic factors- non-living, physical & chemical components in the biosphere
Can you think of any examples: ?
I. On land, abiotic factors include:
surface water ground water air wind soil nutrients temperature precipitation
energy from the sun altitude latitude
b. In aquatic ecosystems, abiotic factors include currents salinity temperature
penetration of sunlight in water,
concentration of nutrients in the water.
** The actions of people can change abiotic factors and disrupt ecosystems in both positive and negative ways.
Ex. Dams, electric power plants, etc.
2. Biotic- all the living or dead components in the biosphere: animals, plants, micro- organisms, paper, decomposed matter, etc.
i. Examples include: competitors, predators, parasites, plants, animals, fungi, and microorganisms.
• Ecology is Organized into Scales of Biological Organization
• Groups: Why would anyone study ecology?
• Groups: why might medical professionals care to know about ecology?
Malaria is spread by mosquitos – wobachia is a bacteria that shortens their lives. What effect can a shorter life span of the mosquito have?
1. The Individual Organism
i. which can be anything from a tiny bacterium to a bear.
ii. Vary in size
iii. Generally self-sufficient
iv. Internally divided by membranes (cells, dermis etc)
v. basics of selection
c.Organismal ecology- study of how individuals meet the challenges of their world
Examples: acquiring nutrients, avoiding predator/parasites, acquiring mates, resource allocation
d. Organismal ecologists often describe themselves in terms of the organisms they study:
Examples: botanists (plants) , ornithologists (birds), herpetologists (amphibians), mammologists, entomologists (insects), arachnologists (spiders), mycologists (fungi), microbiologists (microorganisms)
a. population is a group of the same species found in a given area or located in the same area at a given time.
Ex. White tail deer in oak-hickory forest in SE Pa
A. Population ecology- study of attributes of populations.
Examples: variation in the number of individuals, sex ratios, demographics (birth, death, growth), and genetic makeup of populations
b. Population ecologists often describe themselves as demographers, population geneticists, and evolutionary biologists
a. A community consists of the populations of living organisms that interact with one another.
b.Community ecology- study the causes and consequences of diversity, distributions, and relative abundances of different, interacting species.
Note: Focused on interactions among populations.
c. Community ecologists typically study subsets of whole communities, but tend not to focus on a particular organism.
a. An ecosystem consists of a group of living organisms that interact with each other and the nonliving physical environment as one unit.
b. Land ecosystems - forest, desert, and grasslands.
c. Aquatic ecosystems including ponds, lakes, rivers, streams, wetlands, estuaries, coastal marshes, coral reefs, and the open ocean.
d. Ecosystem ecology- study the movement of chemical & energy currencies through the environment, & how physical factors influence these movements.
Examples: movement of energy, nitrogen, phosphorus, water, carbon
e.Ecosystem ecologists typically focus on a single ecosystem, and one or two essential chemicals.
i.A layer of soil, water, and air that sustains life.
b. The ecology of the biosphere: study the movement of chemical and energetic currencies through the environment, and how physical factors influence these movements
Example: movement of nutrients, energy, or trophic cascades across ecosystems (e.g., land to sea)
6. The units of ecology:
a. taxonomic group of any rank, such as a species, family, or class.
b. different taxon assume different roles in ecosystems
The Study of Ecology
Food Chain: linear series of trophic interactions
1. A food chain is the transfer of energy from one organism to another. As each organism eats or is eaten by another organism, that energy is transferred.
Food chains vs. Food webs
Groups: costs/benefits of either?
A food web gives a more complete picture of the true flow of nutrients and energy through an ecosystem.
III. Trophic level
a. Contains all organisms in a feeding level that are the same number of steps away from the source of energy in ecosystems, the sun
b. As you move up from one trophic level to another in an ecosystem, there is a 90% loss of energy (as heat).
c. An energy pyramid is made up of the trophic levels in a food web and the amount of energy that moves from one level up to the next.
a. Green plants are known as producers because they ‘produce’ their own food from the elements in the environment
2. Consumers (primary, secondary, tertiary)
a. consumer is an organism that gets its energy and nutrients by feeding on other organisms. Many animals are consumers.
b. Primary consumers only eat plants for food and energy.
c. A secondary consumer feeds on primary consumers. The tertiary consumer eats the secondary consumer or the primary consumer.
a. Break down the dead organisms and complete the nutrient cycle by returning nutrients to the soil so that plants can use them again.
4. Organisms can exhibit versatility in their roles!
(primary consumer, secondary consumer etc)
•Groups: Characterize the members of the following food web (producer, primary, secondary, tertiary, quaternary etc)
Ecosystem Components & Health
Overview of Species Interactions
Overview of kinds of species interactions
(pairs: find examples & share)
a. Interspecific __________________________________________________
b. Intraspecific __________________________________________________
c. Competition (____, ____) ______________________________________________________________________________________________
d. Predation (____, ____) ______________________________________________________________________________________________ Examples:
e. Parasitism (____, ____)
f. Mutualism (____, ____)
g. Commensalism (____, ___)
h. Amensalism (____, ____) ______________________________________________________________________________________________
i. Symbiosis – _______________________________________________________________________________
j. Niche - ____________________________________________________________________________________
k. Co-evolution- _____________________________________________________________________________
c. Competition (- , -) both negatively affected
- a contest between organisms for territory, a niche, for resources, mates
B. Predation (+, - ) One helped, one harmed (killed) describes a biological interaction where a predator (an animal that is hunting) feeds on its prey
C. Parasitism ( +, - ) one organism benefits at the expense of another (host)
D. Mutualism ( +,+) each species benefits
E. Commensalism (+,0) one benefits with no effect on other
F. Amensalism (0, - ) one is harmed, the other is unaffected
1. Soil- an integral part of many ecosystems
a. Soil, a renewable resource, is very precious and must be conserved.
b. Geological processes can change the amount and quality of soil in an ecosystem.
c. In some cases, erosion, removes soil faster than it can form.
d. Soil can also be deposited, and thick fertile soil will develop in some areas of sedimentation. This sediment is very nutrient rich soil.
1. Carrying Capacity of an Ecosystem
a. Population decreases and increases are influenced by many factors.
b. Weather conditions, habitat quality, species survival and reproduction all affect population growth.
c. The factor that is most controls population growth is called the limiting factor.
d. Each ecosystem has a carrying capacity, which is the number of individuals of a species that it can support.
Groups: Think of ways humans can increase carrying capacity.
VI. Homeostasis in an Ecosystem
1. The natural stability in an ecosystem that keeps it from undergoing radical change is homeostasis.
a. Ecosystems maintain homeostasis, in part, because the organisms within them have the ability to resist change.
b. Healthy ecosystems maintain an intricate balance, but stresses that can cause change happen all the time. What are some natural stresses? Wildfires, floods, storms.
c. If change is too extreme, an ecosystem can’t repair itself. Examples are important species killed off or removed, pollution disrupts the natural processes, etc.
1. A biome is a geographic region of Earth that is inhabited by a community of distinct types of plant and associated animal species.
a. Biomes are largely defined by climate, especially average annual temperature and precipitation
b. Influences on climate would be latitude and altitude.
2. Land Biomes
a. Forest biomes cover areas with relatively high average yearly rainfall.
b. Tropical rain forests are warm year-round and have almost daily heavy rainfall.
c. Tropical deciduous forest and tropical scrub forest are present as you move away from the equator and as rainfall becomes less steady and intense.
d. Pennsylvania is within the temperate deciduous forest biome. The area is moist with long, warm summers and cold winters.
e. Temperate coniferous forests are in mid-latitude coastal areas that have mild winters and heavy rainfall
f. Northernmost forested areas contain the boreal forest, or taiga, where there are long, cold, dry winters and short, warm summers. Evergreen conifers are the dominant tree species.
a. Grasslands of the tropics and subtropics are often called savanna; they have a distinct wet season and a long, dry season
b. Temperate grasslands cover much of the interior of North America, Eurasia, South America, and Africa. Winters are cold, and summers are hot and dry. The corn belt and vast wheat-growing areas of the U.S. are located in areas of temperate grassland.
A. Competition (- , -)
B. Predation (+, - )
C. Parasitism ( +, - )
Examples: Tapeworm, viruses, bacteria, cuckoo bird (kick out host eggs/baby sitter)
D. Mutualism ( +,+)
Examples: bees & flowers, anemone & clown fish, animals speading seeds of plants
E. Commensalism (+,0
Examples: barnacles on the whale, cattle egrets & live stock
F.Amensalism (0, - )
Examples: Black walnut secretes a chemical that harm neighboring plants, branches fall off trees damaging plants underneath
c. Polar grasslands are also known as tundra. These areas are treeless plains that are cold all year and have very little precipitation.
3. Aquatic Biomes
a. Freshwater- contain less than 1% by volume salt.
a. Freshwater biomes cover a much smaller area than do marine biomes, but almost 41% of the world’s fish species live in them
a.Marine biomes are saltwater biomes that are part of the world’s oceans and cover most of the Earth.
X. Cycles in an Ecosystem
1. The Water Cycle
a. Earth’s water supply is finite.
b. Oceans are the greatest reservoirs of water
a. Water evaporates, condenses, precipitation occurs.
b. Water intake in plants is done by the roots
c. Transpiration (plants) & evaporation (earth/ water sources) allow water to be given back to the atmosphere.
2. The Carbon Cycle
a. Carbon is the building block of life.
b. The ocean, atmosphere, and rocks all store large amounts of carbon. When carbon leaves these reservoirs, it cycles through the environment in several connected ways.
c. Examples of ways carbon cycles between the ocean, atmosphere and living things are: photosynthesis, decomposition of living organisms, formation and burning of fossil fuels.
3. The Nitrogen Cycle
a. Living organisms, people, plants and animals get nitrogen from food.
b. Atmospheric N
c. Nitrogen is an important element in organic compounds.
d. Nitrogen is the most abundant gas in the Earth’s atmosphere for this reason is called atmospheric nitrogen. However, it cannot enter into chemical reactions that allow your cells to use it when you breathe the nitrogen.
XI. Ecological Succession
Ecological succession is a process in which the communities of an ecosystem change over time.
1. Stages of Succession
a. Primary succession occurs in places where an ecosystem never existed.
a. A pioneer species is a hardy species that is one of the first to establish itself at the start of the process of succession and often include mosses and lichen.
b. Process of succession continues until the ecosystem species form a climax community, that is a community that forms in the last stage of succession. Ex. The oak-hickory forest of PA.
c. Catastrophic events can interrupt the process of succession at any stage. Examples: tornado, volcano, hurricane…
b. Secondary Succession is the process that begins in an ecosystem when something has disturbed or destroyed the natural community
a. These areas begin with weeds and grasses as opposed to mosses and lichen.
b. Examples of secondary succession are the Renewal at Yellowstone and the Mount Saint Helens Comeback.
b. A species is a group of organisms that are alike and can breed with each other to produce healthy offspring.
e. Demographics – the statistical data of a population (gender ratios, avg. age etc)
f. Birth rate-the proportion of births to the total population in a place at a given time, expressed as a quantity per 1000
g. Death rate - the proportion of deaths to the total population in a place at a given time, expressed as a quantity per 1000
o. An S-shaped curve shows that the population grows slowly at first, increases more quickly, and then stabilizes.
p. Exponential model –growth of a population multiplies by the same number each week/month/year
l. carrying capacity, which is the number of individuals of a species that it can support.
n. Density dependent factor -Density-dependent factors are limiting factors that depend on the number of organisms in an area
a. Ex: food, shelter, predation, disease
m. Density independent factors - Factors limiting the size of a population whose effect is not dependent on the number of individuals in the population.
a. Ex. flood, fire, natural disasters, which it doesn't matter how dense a pop. is cause they're all going to die.
i. Life expectancy – the probable number of years remaining in the life of an individual determined by statistics. Influenced by factors such as heredity, physical condition, nutrition and role in environment
j. Dispersion- the movement of individuals from their birth site to their breeding site, as well as movement from one breeding to another. Dispersal is defined as any movement that has the potential to lead to gene flow.
3. Desert - is an ecosystem that forms due to the low level of rainfall it receives each year. Deserts cover about 20% of the Earth. There are four major types of desert in this biome - hot and dry, semiarid, coastal, and cold
d. Because less than 1 % of earth’s abundant water is fresh water, water conservation has become an important part of water use planning.
e. Organisms expel water through respiration and elimination
e. Nitrogen enters soil through decomposition of organic material, animal waste & plant matter by bacteria/fungi (nitrogen fixation) creating ammonia & ammonium ions that react with oxygen forming nitrates/nitrites
Nitrates can then be used by plants (which are consumed by animals)
h. Denitrifying bacteria convert soil nitrates into N2
i. Like carbon, nitrogen moves through the various trophic levels of an ecosystem as animals eat plants and other animals eat those animals.
What do you think each term means?
Organism - ______________________________________________
Population - _____________________________________________
i. Very rarely do singular scientists study biosphere-level phenomena. Teams of scientists study biosphere related phenomena
a. interspecific - occurs BETWEEN different species
b. intraspecific - occurs within SAME species
i. Symbiosis – interaction between two different organisms living in close physical association, typically to the advantage of both
j. Niche - a species role in nature, its place or position in an ecosystem,
k. Co-evolution- species that are closely associated in their evolution
k. limiting factor- conditions that limit the growth, abundance, or distribution of an organism or a population of organisms in an ecosystem
h. rate of reproduction - is proportional to both existing population and the amount of available resources
4. Chaparral - composed of a variety of different types of terrain including plains, rocky hills, and mountain slopes.
5. Ice Cap -primarily in polar areas that are always cold and ice builds up such as Antarctica and Greenland
o. Migration movement of individuals into and out of a region
p. Immigration is migration of individuals coming into one region from another region
q. Emigration the exit of individuals from one region-
It can reduces overcrowding in the home range, and increases the likelihood of establishing new populations elsewhere
VII. Biodiversity and Environmental Health
1. biodiversity: the variety of living organisms on Earth
a. the number and types of organisms vary by habitat
b. when habitats are in equilibrium, the number of species is balanced with the resources within in the habitat
c. equilibrium can be disrupted by stress or damage on an ecosystem
d. the health of every ecosystem is directly related to its biodiversity
1. determining the health of an ecosystem by incorporating biological factors as well as examining samples for pollutants et cetera
2. basic premise: certain types of organisms occur and thrive within a limited range of conditions; when these conditions change the numbers and distribution of organisms in the affected site also change
3. Water quality: organisms most commonly used are bottom-dwelling invertebrates
a. present in nearly every aquatic ecosystem
b. easy to collect and identify
c. limited mobility so they can’t avoid poor water quality conditions
d. sensitive to a wide range of environmental impacts, including pollution
e. examples: crayfish, pill bugs, clams, snail, mussels, earthworms, leeches, flies, stoneflies, beetles
4. organisms are caught, identified, and counted and then this information is compared with information gathered previously at the same location or sometimes with a different but similar site
l. Invasive Species - a plant, fungus, or animal species that is not native to a specific location (an introduced species), and which has a tendency to spread to a degree believed to cause damage to the environment, human economy or human health
SOIL MOVED to CYCLES IN ECOSYSTEM!
m. An introduced species (also known as an exotic species) is an organism that is not native to the place or area where it is considered introduced and instead has been accidentally or deliberately transported to the new location by human activity
Biotic factors are both the organisms and their interactions such as how they feed. Including food webs that are based on detrital feeders.
Bacteria and fungi recycle the organics to the inorganic and abiotic eventually but until then the detritus is a part of the biotic interactions