“Ecology, management and the environment are all fundamental topics and can be easily understood by watching documentaries and geographical channels but why is it that when we are put to the test it becomes so difficult to recall and make sense of? Honestly, that question still remains unanswered...
BIO1000A-Introductary Life Sciences
By Amatullah Chiosa
“Ecology, management and the environment are all fundamental topics and can be easily understood by
watching documentaries and geographical channels but why is it that when we are put to the test it becomes
so difficult to recall and make sense of? Honestly, that question still remains unanswered, yet this document
serves as a way to create a visual image like the ones created in documentaries so that it can be easily
understood. Best of luck!”
CONCEPTS COVERED
Overview of ecology
Ecosystems
Species interactions and communities
Climate biodiversity
, Introduction to Ecology and Scales
Ecology- “the scientific study between organisms and the environment.”
Ecology can be broken down into further sections to broaden the study and examine different needs
at different levels. These levels in ascending order are as follows:
Organism ecology
↓
Population ecology
↓
Community ecology
↓
Ecosystem ecology
↓
Landscape ecology
↓
Global ecology
To understand these scales, we’d need to interpret and examine the different types of levels. A
population is a group of organisms living in the same area at the same time. Whilst a community
is a group of different populations living in the same area at the same time. And ecosystem is a
community of organisms as well as the environment which they interact with. A landscape is a
collection of ecosystems whereas the biosphere is the global ecosystem. The biosphere is important
as it is the collection of all the ecosystems of the planet.
These levels can be compared to the education system where:
❖ the organism is the student
❖ the population is the students
❖ the community is the students and the staffing body
❖ the ecosystem is the schooling environment as well as the students and staffing body
❖ the landscape is the collection of schools in the area
❖ the biosphere is the collection of schools in the world
Other factors that must be taken into consideration when completing this section is the
environment. Factors that are part of the environment but influence the type of organisms that stay
in a population are:
,Biotic factors- factors that are living that influence the population. E.g.: the type of plants; the
type of decomposers in that area.
Abiotic factors- factors that are non-living that influence the population. E.g.: the type of soil,
water, or temperature in that ecosystem.
Note: the (A) in front of a term means “non” in most cases.
Energy in ecosystems
Unlike in the previous section, whereby scales were dependent by the number of species, environ-
ment, and time; tropic levels in an ecosystem require energy to be fueled to fulfill life processes
and to replace the energy lost to heat. Energy transfer can also be determined by distinguishing
which organisms are being fed on. This is what is called tropic levels.
To understand why we use tropic levels and how we use them to determine which animal will fit
in where in the food chain/web; we need to revise the 2 laws of thermodynamics.
1st law of thermodynamics- “energy cannot be created or destroyed but it can be transformed
from one form to another.”
2nd law of thermodynamics- “whenever energy is changed from one form to another, we end up
with lower quality or less useable energy than we started with.”
The two major tropic levels:
Producers(autotrophs): uses photosynthesis to convert solar energy to usable energy.
Consumers(heterotrophs): uses cellular respiration to convert energy from consuming food to
usable energy. They transfer energy amongst each other chemically through feeding.
Primary consumers Obtain energy by feeding off producers
Secondary consumers Obtain energy by feeding off primary
consumers
Tertiary consumers Obtain energy by feeding off secondary
consumers
Omnivores Obtain energy by feeding off all tropic
levels
Detritivores Obtain energy by feeding on waste and
dead bodies
, According to the 2nd law of thermodynamics, as energy moves from producers and amongst con-
sumers; a little bit of that energy is lost as heat. This is because organisms are exothermic. They
release heat as energy moves from one tropic level to another. This heat is released into the eco-
system. This means the last consumer will have less energy to feed on than the primary consumer.
It is for this reason that they are so many Eventually any energy that is left after a decomposer has
died will be lost to heat. Remember that according to the first law of thermodynamics, no energy
is lost or destroyed, it is always converted to another form of energy.
Difference between a food web and food chain:
Food webs involve many different animals branching into each other as energy is being
passed on using complex trophic interactions.
Food chains involves one animal per tropic level through a linear path of energy transfer.
Q: how can we tell how far solar energy that is converted during the photosynthesis of a
producer can go?
A: the range of production of solar energy conversion into usable energy decides the
amount of energy that can fuel an entire ecosystem.
Primary Productivity:
To understand how the main source of energy from a producer travels to several different consum-
ers before being lost to heat; there are certain terminology that needs to be clarified. In simple
terms, biomass is the total mass of a species.
There are two types of primary productivity:
1. gross primary productivity
2. net primary productivity
The gross primary productivity is the amount of chemical energy in living tissue that a producer
creates per unit time. The units for this measurement: kcal/m2/year or kgC/m2/year or kJ/m2/year.
The gross primary productivity depends on:
1. the amount of photosynthetic tissue a producer has.
2. how long photosynthesis takes place.
Maintenance respiration is the energy that is used up by the body.
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