BIODIVERSITY (BSB 123)
Prof. FS Wakjira
fwakjira@buan.ac.bw
March 2024
BSB123 Biodiversity course outline
Study the Course Outline (eduhub)
The course is divided into five sections
I. Evolution and Taxonomy (Prof FS Wakjira)
II. Diversity of prokaryote, Protoctista and fungi (Microbiology) (Mrs M Batlhophi)
III. Plant diversity (Dr T Selebatso)
IV. Animal diversity (Prof SW Makhabu)
V. Ecology (Prof Makhabu) [2WKs the rest each 3WKs]
Ask any questions
All sections have practical sessions
• Week 1. Lab Induction
• Recap about lab protocols and regulations
Evolution and Taxonomy
• Week 2: Evolution
• Geological timeline activity
• Mechanisms of evolution
• Week 3: Taxonomy
• Identification of organisms using keys
• Tutorial session will start next week!
Modes of assessment
Course assessment:
• Continuous assessment (CA) 50%: Exam 50%
• Continuous Assessment shall comprise the following:
• (a) Two theory tests and two practical tests
• Theory tests = 30%
• Practical tests = 40%
• Theory Tests dates:
• Test 1: 23/04/2024
• Test 2: 28/05/2024
• (b) Online quizzes = 10%
• (c) Laboratory reports = 20%
Check course outline for partical Tests dates
Expectations
Write down your expectations (4 or 5 points)
Objectives of the course
• By the end of the course, you should be able to:
• Understand evolutionary basis of biodiversity and recognize the value of
taxonomy.
• Identify and describe living organisms, their classification and
evolutionary relationships.
• Explain the three domains and the five- kingdom classification system.
• Discuss forms and functions of living organisms.
• Examine interrelationships among the organisms and their abiotic
environment.
• Define some taxonomic and evolutionary terminology.
• Appreciate agricultural ecology.
What is Biodiversity?
Objectives
• In this lecture we shall talk about:
• Definition and concept of Biodiversity
• Value of Biodiversity
• Threats to Biodiversity
• Biodiversity conservation
Understanding Biodiversity
Conservation
Biodiversity loss
Explore and use
Classifying (naming) and describing
Understanding the dynamics and their relationships
How did biodiversity evolve?
What is biodiversity?
Via Evolution! Life on earth are related/connected
Diversity of life forms! Life on Earth have great diversity
What is biodiversity?
• The term biodiversity was first coined by Edward O. Wilson in 1986
• Biodiversity is a short form of Biological Diversity
• Bio – living organisms/life
• Diversity – variability
• Living things: all the organisms descended from a single-celled ancestor.
• Biodiversity
• the variability among living organisms from all sources including, inter alia, terrestrial, marine and
other aquatic ecosystems and the ecological complexes of which they are part (CBD definition)
• It is the degree of variation of life forms within an ecosystem or entire planet
Biodiversity has three components
• Diversity within species, between
species and of ecosystems
Ecosystem diversity
Species diversity
Genetic diversity
• What is genetic diversity?
• It describes the variation in the number and types of genes as well as
chromosomes present in different species.
• It refers to the diversity (or genetic variability) within species
• The magnitude of variation in genes of a species increases with increase in
size and environmental parameters of the habitat.
• Each individual species possesses genes which are the source of
its own unique features:
• In human beings, for example, the huge variety of people's faces
reflects each person's genetic individuality.
• Genetic diversity has the following importance:
• It helps in speciation or evolution of new species;
• It is useful in adaptation to changes in environmental
conditions;
• It is important for agricultural productivity and development.
What is Species diversity?
It is defined as the number of species and abundance of
each species that live in a particular location.
The number of species that live in a certain location is called
species richness.
No. of plant species per ha
No. of animal species per ha
No. of cows per ha
The richness of a species tells about the extent of biodiversity
of a site and provides a means for comparing different sites.
The species richness depends largely on climatic conditions.
When a species is confined entirely to a particular area, it is
termed as endemic species.
No. of plant species in
Botswana
Number of bird species in
Botswana
• How many species do you think exist on Earth?
• There are approximately 1.8 million different species classified on Earth
(~1 million are insects)
• New species are being discovered each year.
• Scientists estimate that there may be between 5 to 100 million species
that actually live on Earth.
• These diversity are the product of nearly 4 billion years of evolution
• Each year, approximately 13,000 more species are described.
• The hottest spots for species diversity are tropical rainforests.
• Tropical rainforests comprise only 7% of all land on Earth yet are home to
nearly 50% of all the species on Earth.
• What is ecosystem diversity?
• It refers to the diversity of ecosystems in
a particular geographic location.
• An ecosystem is, in turn, a system that
includes all living organisms (biotic
factors) and the physical environment
(abiotic factors) functioning together as
a unit.
• Ecosystems may be terrestrial,
freshwater, marine, and artificial
Patterns of biodiversity distribution: global, regional & local
Biodiversity unequal distributed in space and time
Some areas highly diverse and some areas poorly diverse
Below maps show patterns of global distribution of some groups of organisms

https://biodiversitymapping.org/
Pattern of distribution: at microsite level
Why such biodiversity variation across space?
Regional geological history
Environmental factors (e.g., climate, topography, edaphic factors)
Ecosystem productivity (more solar energy, water availability, and a relatively constant and predictable
environment
Habitat heterogeneity and suitability,
Competition
Predation
Land use history and human factor
Etc
Why should we care for biodiversity?
WE depends on biodiversity for our existence
Life on earth depend on biodiversity
Source: Millennium Ecosystem Assessment
Values of Biodiversity
There are direct and indirect benefits of biodiversity
⚫
Direct economic value
- Humans depends on biodiversity for food, clothing,
energy, medicine and shelter
⚫
Environmental regulation
– prevent erosion, purify water, recycle CO2
– regulate climate, recycle nutrients through
decomposition
⚫
Psychological value – direct or indirect enjoyment with
nature
⚫
Intrinsic value – independent of humans/ they have the
right to live
Agricultural:
Of 80,000 known edible plants on the planet, we depend on 20 species to provide 90% of global food supply.
Corn, rice and wheat are 50% alone!
They are huge potential for future food sources
Medicinal
Medicinal: 40% of modern medicines come from plants/animals/fungi, 95% of known plant
species have never been tested for medicinal value
Huge potential for future drug development
The benefits and services provided by biodiversity include:
Maintenance of soil quality
Maintenance of air quality
Maintenance of water quality
Pest control and mitigation of natural disasters
Detoxification and decomposition of wastes
Pollination
Crop production
Provision of food security
Provision of health care – medicines
Income generation
Spiritual and cultural value
Climate regulation
Threats to Biodiversity?
Despite their importance, biodiversity loss has become a significant issue for scientists and
policy-makers recently
Species are becoming extinct at the fastest rate known in geological history and most of these
extinctions have been tied to human activity
Habitat loss and fragmentation
Introduction of exotic species
Over-exploitation
Pollution
Global climate change
Change in ecosystem composition
Habita fragmentation
Entact ecosystem
Urbanization
Conversion
Pollution
Overexploitation
Current extinction rates are unusually high
Source: Millennium Ecosystem Assessment
What is biodiversity conservation?
• Maintaining the diversity of species, habitats, and the interrelationships between organisms and the
environment to keep ecosystems healthy and functioning.
Conservation is defined as management of human use of biodiversity so that it may yield sustainable benefit to
the present generation while maintaining its potential to meet the needs and aspirations of future generations.
There are two basic strategies of biodiversity conservation
In-situ (on site) and
Protected Area Systems
National Parks
Biosphere reserves
Ex-situ (off site)
Seed banks
Gene banks
Botanical Gardens
Zoological gardens
Sperm/egg banks
Frozen embryos
Ex-situ conservation
It is defined as “the conservation of component of biological diversity (Sample of genetic
diversity, particularly of endangered species) outside their natural habitats”.
It involves maintenance and breeding of endangered plant and animal species under partially
or wholly controlled conditions. E.g., Zoos, Botanical Gardens, Aquaria, Nurseries, DNA
bank, Seed bank, Gene bank etc.
Storage of tissues, seeds, pollen, semen, ovules, embryos, microbial cultures, DNA
There are more than 1500 Botanical gardens in the world containing more than 80,000
species.
There are more than 800 zoos around the world with about 3,000 species of mammals,
birds, reptiles and amphibians
Provides “insurance policy” and can play important role in recovery programs.
In-situ conservation
It simply means conservation of species in its natural
ecosystem or even in manmade ecosystems.
This strategy emphasizes protection of total ecosystem
through a network of “protected area”.
Protected Areas: an area of land and / or sea specially
dedicated to the protection and maintenance of biological
diversity and managed through legal effective means.
There are different categories of protected areas which are
managed with different objectives. These include; Biosphere
reserves ,National parks, Wildlife Sanctuaries etc.
Setting Priorities for Biodiversity Conservation
It is impossible to actively conserve all species/ecosystem because of limited time and money.
As a result, we must make decisions about how to target conservation efforts and limited resources can
have the greatest impact.
So, how do we decide?
Setting priorities species/areas
What is the Goal of Conservation?
Conservation efforts focus on protecting entire ecosystems as well as single species.
Protecting an ecosystem will ensure that the natural habitats and the interactions of many different species
are preserved at the same time.
Conservation Challenges
Protecting resources for the future can require people to change the way they earn their living today.
Conservation regulations must be informed by solid research and must try to maximize benefits while
minimizing economic costs.
How to measure biodiversity?
Biodiversity can be quantified in many ways.
Genetic diversity
Two main factors considered by ecologists for measuring species diversity:
Species richness
Species evenness
Ecosystem/habitat diversity
Functional diversity
Structural diversity
Different types indices (indexes) are used to analysis