Ecology, Evolution and Biodiversity

1. Course: ECOLOGY, BIODIVERSITY &
EVOLUTION
Course code: BT144
Credit Hours: 3

2. Course Objective
• This course aims to introduce students to the
fundamentals of ecology, biological diversity
and evolution – key areas that are pertinent to
modern day biology.

3. Course outline
• Introduction;
• Ecosystem and ecological pyramids;
• Role of environment on phenotype of organisms;
• Food chain, webs and trophic levels;
• Factors influencing environment; impact of
urbanization and industry on environment;
• Population: air, water, land, thermal, radiation and
noise;
• Community ecology;
• Atmosphere – composition and cycles;
• Pollution; climate change (greenhouse effect and
global warming)

4. • Ozone layer – composition and state across the globe;
• Waste and sewerage processing and disposal;
• Microbes, plants and animal species;
• Comparative study of life forms;
• Features and characteristics of bacteria, archaea and
eukaryotes;
• Phylogenetic relationships between the three kingdoms;
• Evolution of different members belonging to each of the
three domains of life (with specific examples); models of
speciation; causes and consequences of extinction.

6. Ecology
• is the study of the relationships between
living organisms, including humans, and
their physical environment.
• Ecology considers organisms at the
individual, population, community, ecosystem,
and biosphere level.

7. What is studied in ecology?
• The abundance, biomass, and distribution
of organisms in the context of the
environment
• Life processes, antifragility, interactions,
and adaptations
• The movement of materials
and energy through living communities
• The successional development of
ecosystems
• Cooperation, competition, and predation
within and between species
• Patterns of biodiversity and its effect on
ecosystem processes

8. Biodiversity
• Biodiversity (an abbreviation of "biological
diversity") describes the diversity of life from
genes to ecosystems and spans every level of
biological organization.
• Biodiversity includes species
diversity, ecosystem diversity, and genetic
diversity

9. Habitat
• The habitat of a species describes the
environment over which a species is known to
occur and the type of community that is
formed as a result.

11. Niche
• "the set of biotic and abiotic conditions in
which a species is able to persist and maintain
stable population sizes."

12. Food webs
• A food web is the ecological network.
• The simplified linear feeding pathways that move
from a basal trophic species to a top consumer is
called the food chain.
• larger interlocking pattern of food chains in an
ecological community creates a complex food
web.
• Food webs are a type of concept map or
a heuristic device that is used to illustrate and
study pathways of energy and material flows.

14. Trophic levels
• A trophic level (from Greek troph, τροφή, trophē,
meaning "food" or "feeding") is "a group of
organisms acquiring a considerable majority of its
energy from the lower adjacent level (according
to ecological pyramids) nearer the abiotic
source.“
• Biodiversity within ecosystems can be organized
into trophic pyramids, in which the vertical
dimension represents feeding relations that
become further removed from the base of the
food chain up toward top predators, and the
horizontal dimension represents
the abundance or biomass at each level.

16. What is an Ecological Pyramid?
• An ecological pyramid is a graphical
representation of the relationship between
the different living organisms at different
trophic levels.
• Types of Ecological Pyramid
– Pyramid of Numbers
– Pyramid of Biomass
– Pyramid of Energy

17. Pyramid of Numbers
• In this type of ecological pyramid, the number
of organisms in each trophic level is
considered as a level in the pyramid. The
pyramid of numbers is usually upright except
for some situations like that of the detritus
food chain, where many organisms feed on
one dead plant or animal.

18. Pyramid of Biomass
• In this particular type of ecological pyramid,
each level takes into account the amount
of biomass produced by each trophic level.
The pyramid of biomass is also upright except
for that observed in oceans where large
numbers of zooplanktons depend on a
relatively smaller number of phytoplanktons.

19. Pyramid of Energy
• Pyramid of energy is the only type of
ecological pyramid, which is always upright as
the energy flow in a food chain is always
unidirectional. Also, with every increasing
trophic level, some energy is lost into the
environment.

20. Importance of Ecological Pyramid
• They show the feeding of different organisms
in different ecosystems.
• It shows the efficiency of energy transfer.
• The condition of the ecosystem can be
monitored, and any further damage can be
prevented.

21. Ecosystem
• The complex of living organisms, their
physical environment, and all their
interrelationships in a particular unit of space.

22. Environmental Effects on Phenotype
• Epigenetics: Epigenetics is the study of how your
behaviors and environment can cause changes
that affect the way your genes work.
• Types of epigenetics:
– DNA Methylation. DNA methylation works by adding a
chemical group to DNA. ...
– Histone modification. DNA wraps around proteins
called histones.
– Non-coding RNA. Your DNA is used as instructions for
making coding and non-coding RNA.

23. Phenotypic plasticity
• To see a purposeful and driven form of
environmental variation, consider the
snowshoe hare. Like many animals that live in
cold, snowy regions, the snowshoe hare goes
through a seasonal molting event. Though the
hare is pure white during the winter months,
the hair will become brown in the summer.
These two different color phenotypes help the
hare stay camouflaged in both seasons. This is
known as phenotypic plasticity.

24. A hare during a molting event, halfway between the
white winter coat and the brown summer coat. > 600
genes involved in epigenetic changes.. Environmental
cues …. Stimulate signal transduction pathways- turn
on hair regrowth genes and pigment producing genes..
Reprodctive hormones….Evolutionary advantage-
camouflaged and reproduction at right time o the year

25. melanin production
Tanning is a form of phenotypic change from
lighter skin to darker skin, stimulated by UV
rays. The process of tanning is caused by the
release of melanin stimulated by UV light
damage.

26. temperature-dependent sex
determination
In reptiles, each individual receives the exact same set of chromosomes. If the
egg is relatively cold as it incubates, the chromosome will create male hormones
and the offspring will be male. If the egg is relatively warm as it incubates, the
chromosomes release female hormones and the offspring will be female.