Download Unit 1: General Ecology

Unit 1: General Ecology
Examples
Different types of species of birds forage for insects in the same tree, with each species focusing on a
different part of the tree.
Many species of Finch on the Galapagos Islands have different size beaks, they eat different size seeds so
they don’t compete for the same resources.
What is Ecology?
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The branch of biology that deals with the relations of organisms to one another and their physical
surroundings.
Scientific study of the distributions, abundance and relations of organisms and their reaction to the
environment.
Ecology includes the study of plant and animal populations, plant and animal communities and
ecosystems.
The purpose of Ecology is to provide knowledge about the way the worldworks and provide evidence
on the difference between the natural world and people.
The word “Ecology” comes from the Greek oikos, meaning “household” or “place to live”.
Levels of Organization
There are 5 different levels of organization: Individual, Population, Community, Ecostsysem, Biome, and
Biosphere.
Interesting Facts
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The word “Ecology” comes from the Greek oikos, meaning “household” or “place to live”.
Ecology developed substantially in the 18th and 19th century.
Hippocrates and Aristotle were among the 1st record scientists to write down their observations on
what could be considered “Ecology”.
Biotic vs. Abiotic Factors
Biotic Factors:
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Biotic factors are living things in an ecosystem or the things that were once living.
All biotic factors can reproduce (autotrophs & heterotrophs)
Biotic factors are obtained from the biosphere
Examples of biotic things: Animals, birds, plants, fungi, humans, & trees.
Biotic vs. Abiotic Factors
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Abiotic factors are the nonliving chemical and physical parts of the environment
They affect living organisms.
Abiotic organisms are obtained from the lithosphere, atmosphere, and hydrosphere.
Abiotic components affect the ability for biotic organisms to survive and reproduce.
Examples of abiotic things: Water, soil, air, and sunlight
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This topic is relevant to Environmental Science because it shows that the abiotic factors are what keeps
biotic factors alive and reproducing in the ecosystems.
Levels of Ecological Organization
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There are six main levels to Ecological Organization:
Individual: is any living thing or organism.
Population: A group of individuals of a given species that live in a specific geographic area at a
given time. Individuals from other groups.
Community:
This includes all the populations in a specific area at a given time. A community includes
populations of organisms of different species.
Ecosystems: ecosystems include more than a community of living organisms (abiotic) interacting
with the environment (abiotic). At this level note how they depend on other abiotic factors such
as rocks, water, air and temperature.
Biome: is a set of ecosystems sharing similar characteristics with their abiotic factors adapted to
their environments.
Biosphere: When we consider all the different biomes, each blending into the other, will all humans
living in many different geographic areas, we form a huge community of humans, animals and
plants, in their defined habitats
What is a Biome?
A Biome is the way that we divide The Earth based on Climate, Inhabitants, and types of soil
Types of biomes
Aquatic: Marine and Freshwater
Deserts: Hot & Dry, Semiarid, Coastal
Forests: Boreal, Temperate,Tropical
Grasslands: Savanna, Temperate, Tropical
Tundras: Arctic and alpine
What is Symbiosis?
Symbiosis: The interaction between two different organisms living in close association, typically to the
advantage of both.
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There are three types of symbiosis: Commensalism, Mutualism, and Parasitism
Types of Symbiosis
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Commensalism- One species benefits from relationship, other is unaffected.
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Mutualism- Both species benefit from relationship
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Parasitism- Host provides food and shelter for parasite, parasite damages the host
Examples
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Commensalism- Barnacles attach themselves to whales. The barnacles have a home, and the whale
has no benefit or disadvantage.
Mutualism- Oxpecker birds sit on zebras and rhinos and eat the bugs landing on them. The bird gets a
meal, the zebra/rhino gets cleaned.
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Parasitism- Fleas on animals get food and shelter while the host suffers itchy bites and the possibility
of disease.
Difference Between Habitat and Niche
Habitat- It is a specific place or locality where a community resides.
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A habitat has a number of niches.
Habitat supports a number of species.
A number of environmental variables occur in a habitat.
A species does not change its habitat.
Niche
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It is an ecological component of habitat which is delimited by functioning of an organism.
A niche does not have components.
Niche supports a single species.
Niche has a specific set of environmental regimes.
A species may live in more than one niche in different stages of its life cycle.
The Competitive Exclusion Principle
-also referred to as Gause’s Law
-states that two species that compete for the same resources cannot stably coexist in the same niche.
-one competitor will always have a slight advantage over the other
-this could lead to the extinction of one species or force the weaker species into a different ecological niche.
Specific Example: Squirrels in Britain
The population of the Red Squirrel in Britain has decreased due to competitive exclusion, disease,
and the disappearance of mature forests in the lowlands of Britain. Because of this the Grey
Squirrel has adapted to parks and gardens, allowing their population to increase and ultimately
replace the Red Squirrel.
Relevance to Environmental Science
The Competitive Exclusion Principle is relative to environmental science because it affects certain
niches and organisms, ultimately affecting the study of our environment.
What is Carrying Capacity?
Carrying Capacity- (noun) The number of individuals of a particular species capable of surviving in a
particular environment over long periods of time and dependent on the effects of the limiting factor.
An example of carrying capacity is the number of individuals that survive a remote island after a shipwreck,
which depends on the quantity of resources found in the ecosystem.
What is a Limiting Factors?
Limiting Factor- (noun) A factor present in an environment that controls a process, particularly the growth,
abundance or distribution of a population of organisms in an ecosystem.
Examples of limiting factors are abnormal weather patterns, and seasonal cycles.
What is Sustainability?