Environmental Science
Unit 5
Biodiversity
Species diversity, Taxonomy, Adaptations,
Florida’s diverse ecosystems, Ecosystem Services,
Evolution, Natural Selection, Human Factor,
Speciation, Extinction, Endangered Species,
Threatened species, Invasive species, CITES,
Species Survival Plan
Chapters 7 & 5
Vocabulary Terms to Define (26)
• Biodiversity
• Ecosystem diversity
• Genetic diversity
• Species diversity
• Taxonomical key
• Adaptation
• Artificial selection
• Evolution
• Extirpation
• Genetic drift
• Mutation
• Biodiversity hotspot
• Gene pool
• Natural selection
• Speciation
• Variation
• Endangered species
• Endangered Species Act
• Endemic
• Extinction
• Captive breeding
• Habitat fragmentation
• Invasive species
• Species Survival Plan
• Poaching
• Threatened species
Biodiversity – see Chp. 7
• Biodiversity – the variety of life
across all levels of ecological
organization. Includes:
• Genetic diversity – differences in
DNA among individuals/species
• Species diversity - # or variety of
species in a given area
• Ecosystem diversity – variety of
ecosystems/habitats/communities
Species Diversity
• The # or variety of species in a particular region
• The most commonly used measure of the
biodiversity of an area
• Encyclopedia of Life – massive project underway to
provide an accessible online library of worldwide
species
• Speciation – the process by which new species are
generated. Caused by geographic separation,
mutations, etc. Happens over a long period of time.
• Extinction decreases species diversity
• Immigration/emigration may increase or decrease
diversity locally
Genetic Diversity
• Describes the differences in DNA among individuals within species
and populations; all individuals vary genetically to some degree.
• Genetic diversity provides the raw material for adaptations to local
conditions. Ex. Hair coat thickness
• Populations with little genetic diversity have a reduced ability to
withstand environmental change, therefore they can be more
vulnerable to disease and may produce weak or defective
offspring
Ecosystem Diversity
• Biodiversity above the species level
• The number and variety of ecosystems within a given area
• Can be community types and habitats
• Ex. Seashore of rocky & sandy beaches; Ocean waters
Classification
• Taxonomy – the study of classifying species according to an
organism’s physical appearance & genetic makeup
• Taxonomic groups – the hierarchy of categories
• Domains – Kingdoms – Phylum – Classes – Orders – Families –
Genus species
• Scientific name: Genus species – binomial nomenclature
• Ex. – Tiger (Panthera tigris), Jaguar (Panthera onca), Leopard
(Panthera pardus), African Lion (Panthera leo) v.s. Bobcat (Felis
rufus) and Cheetah (Acinonyx jubatus). However, all cats are in the
Family Felidae.
Domain
• Subspecies – population of organisms that have the same
genetically based characteristics but differ from members in a
different area. Ex. – Siberian tiger (Panthera tigris altaica)
Taxonomy Lab
• Domains are the broadest, largest category
• From there we divide into Kingdoms, then
Phylums, then Class, then Order, then Family,
then Genus, and finally the most specific
category Species
• The scientific name is Genus species – binomial
nomenclature
• Your task as a group is to classify all of the
items on the demo table down to a scientific
name for each…….8 levels!!!
• The most similar items will have the same
Genus and different species names.
Items to classify:
• 2 graduated cylinders
• 4 Pyrex beakers
• 1 pitcher/beaker
• 2 Erlenmeyer flasks
• Ruler
• Dissection scissors
• Bottle brush
• Funnel
• Petri dish
• Dissection tweezers
• Eye dropper
• Spatula/stirrer
Note that the items are
plastic, glass or metal.
They are all used in a
science classroom. They
are made by different
manufacturers and have
different purposes. Some
are very closely related.
Domain
Kingdom
Phylum
Class
Order
Family
Genus species
Biodiversity Distribution
• Measuring biodiversity is hard as species are often not
evenly distributed (40% of insects are beetles)
• Scientists have identified between 1.7-2million species of
plants, animals, fungi and microorganisms; but estimates
are really between 3-100 million species (5-30 million)
• Why do estimates vary so much? We have only explored
about 3% of the oceans, many bacteria & fungi are tiny &
easily overlooked, some species are hard to tell apart,
and some became extinct before even being discovered
• Latitude gradient – a pattern of species richness the
closer you get to the equator
• Diversity patterns vary with habitat type: the more
diverse the habitat, the more species variation
Biodiversity Benefits
• Ecosystem services – purification of air & water, control of pests &
disease, decomposition of wastes, food, fuel, and fiber
• High levels of biodiversity increase stability of ecosystems
• Removal of some species can be replaced, but not keystone species
• In agriculture, genetic diversity gives resistance to pests & disease and
greater yields
• Many common medicines come from plants, including plants that
hold cures to diseases (rosy periwinkle compounds are used to treat
Hodgkin’s lymphoma and leukemia)
• Direct source of income from ecotourism
7.1 review
1. Explain the differences among genetic diversity, species
diversity, and ecosystem diversity.
2. Do the location and general biodiversity of tropical rain
forests and boreal forests agree with what you would
predict according to the latitudinal gradient pattern?
Explain your answer (hint: look at biome map in Chp. 6)
3. You are trying to convince a friend about the
importance of protecting biodiversity. Which one of the
economic benefits discussed (ecosystem function,
agricultural, medical, recreational) makes the strongest
argument? Why?
Extinction & Biodiversity Loss
• Humans have been the cause of biodiversity losses
throughout history. Losses tend to follow colonization
• Once extinct, a species can never return
• Extirpation – the disappearance of a particular
population from a given area, but not of the entire
species globally
• Mass extinctions – when extinction rates surpass the
normal background rate; these have occurred at least 5
times in Earth’s history, with 20-50% species lost
• Current extinction rates are 100-1000 times greater
than the usual background rate, leading scientists to
believe we are in the middle of a 6th mass extinction
Categorizing Risk
• Scientists classify at risk species to track biodiversity
trends
• Endangered species – one that is at serious risk of
extinction
• Threatened species – one that is likely to become
endangered soon throughout all or part of its range
• As of 2009, 1321 species in U.S. are officially listed as
either endangered or threatened; 21% of mammal species
worldwide, including all subspecies of tiger, are
threatened or endangered
• The International Union for the Conservation of Nature
(IUCN) maintains the Red List of Threatened Species
Living Planet Index
• Living Planet Index – developed by scientists
at the World Wildlife Fund (WWF) and the
United Nations Environment Programme
(UNEP) to track species decline
• It summarizes population trends for a set
number of terrestrial, freshwater, and marine
species
• Closely monitored and provides reliable data
• Between 1970 and 2010, the Living Planet
Index fell by 52%.
Causes of Biodiversity Loss
• Complex & difficult to determine
• 4 Primary Causes of population decline:
• Habitat change and loss
• Invasive species
• Pollution
• Overharvesting
• Many scientists think global climate
change will become a greater factor in
the future
Habitat Fragmentation
• When the habitat is split up so you end up with “islands” of
suitable habitat area surrounded by “seas” of unsuitable habitat
• Often caused by clearing forests for road-building or logging,
removing the food, shelter & other resources for forest-dwellers
• Ex. – Sikhote-Alin Mountains and the Siberian Tiger
• In general, the larger the fragment or “island,” the more species
that area can support
• The smaller the fragment or “island,” the faster it tends to lose
biodiversity
• Habitat change or loss is the greatest cause of biodiversity loss
today!
• Ex. – less than 1% of the prairies native to N. America’s Great
Plains remain….the rest has been converted into farmland.
Other Causes of Loss of Biodiversity
Invasive Species – lack limiting resources, some-times
push native species toward extinction
• Most organisms introduced do not survive, but some
survive too well. Most are harmful, very few are beneficial
Pollution – heavy metals, fertilizers, pesticides, & other
toxic chemicals poison people & wildlife
Overharvesting – occurs when humans hunt, fish, or
harvest a species faster than it can replenish its
population. Large, few in #, long-lived, & raising few
young in its lifetime are vulnerable by hunting (ex. –
Siberian tiger)
• Poaching – illegal capture or killing of an organism
Climate Change – has global effects on biodiversity
Small Group Work
• What is the Living Planet Index and what does it suggest about
current biodiversity trends?
• What are the major factors affecting biodiversity today?
Which one currently has the greatest overall effect? How is
climate change different from the other factors?
• Suppose someone tells you that human development
increases biodiversity. When a forest is fragmented, he or she
argues, new habitats such as grassy lots & gardens may be
introduced to an area and allow additional species to live
there. Do you agree? Explain your answer.
• 7.2 packet
Evolution
• Biological evolution occurs through mutations,
migrations, genetic drift, and natural selection
• Evolution means “change over time.”
• Biological evolution – a change in a population’s gene pool
over time
• Gene pool – includes all genes present in a population
• Gene – sequence of DNA that codes for a particular trait
• Any change to a population over generations, in terms
of traits expressed, indicates biological evolution has
occurred
• There are four primary mechanisms for evolution:
Mutation, Migration, Genetic Drift, Natural Selection
Mutations
• A mutation is a change in DNA
• Mutations give rise to genetic variation
among individuals
• If a mutation occurs in a sperm or egg cell,
it will be passed on to the next generation,
and over many generations evolution will
occur
Migration
• Immigration into or Emigration out of a
population could cause a change in the
proportion of that trait in the population
• Over generations, evolution occurs
because of this gene flow.
Genetic Drift
• Genetic Drift - biological evolution that
occurs by chance
• Sometimes an unusual event, like a
natural disaster or run-in with a fishing
net, kills or somehow separates all but
a few individuals from a population
• The next generation would have a
different gene pool from the original
population just by chance
Natural Selection
• Process by which traits that improve an
organism’s chances for survival &
reproduction are passed on more
frequently to future generations than
those that do not
• Ex. – if striped fish were more attractive
to mates, or better able to avoid
predation than solid fish, their genes
would be passed on to the next
generation, and over time evolution
would occur
Conditions of Natural Selection
1. Organisms produce more offspring than can survive
• This creates a struggle for survival among organisms in their
environment, with some having an advantage
2. Individuals of a species vary in their characteristics
• Not every member of a species is the same
• Variations among members are due to differences in both
genes and the environment in which the genes are expressed
3. Individuals vary in their fitness
• Some variations can be harmful or helpful
• Individuals with helpful variations are better suited to their
environment, therefore more likely to succeed, breed, and
pass on their traits to the next generation
• Fitness – how reproductively successful it is in its environment
• Adaptation – a heritable trait that increases one’s fitness
Survival of the Fittest
• An organism with high fitness will produce
more offspring, passing its genes on more
frequently than an organism with low fitness.
• The next generation should receive a higher
proportion of fitter individuals.
• Therefore, when organisms evolve, they
maximize their success in a given environment
(survival of the fittest)
• However, environments can change, organisms
may move to new places, and new conditions
encountered; so the fittest in one place may
not be the fittest forever.
Artificial Selection
• Most familiar is selective breeding of animals &
crops
• Process of selection conducted under human
direction
• All breeds of dogs are variations on a single
species. The breeds remain “true” by only allowing
like individuals to breed. Any 2 dogs can interbreed
and produce offspring.
• Agriculture comes from selectively breeding plants
to produce the crops we depend on for food.
Brassica oleracea has given rise to broccoli,
cauliflower, cabbage, and brussels sprouts.
Speciation
• The process by which new species are generated
• The most important speciation is that caused by
geographic separation of populations (allopatric
speciation). The mutations that occur cannot
spread to other populations, and over time
become different enough that interbreeding is no
longer possible.
• Can be caused by glacial ice sheets, major rivers
changing course, dry climates, islands forming, etc.
• Through speciation, single species can generate
multiple species, which generate more.
Extinction
• The disappearance of a species………….forever!
• Scientists estimate that 99% of all species that ever lived
are now gone.
• The # of species on Earth at any given time is equal to the #
added through speciation minus the # removed by
extinction.
• In general, extinction occurs when environmental
conditions change rapidly or severely enough species
cannot adapt.
• Background extinction rate – rate at which the naturally
occurring extinction occurs
• Mass extinction – episodes that occur at widely spaced
intervals and are at such staggering proportions that a large
portion of Earth’s species are wiped out
5.1 Review – Small Groups
• Explain why an ecologist must consider both speciation and extinction
when analyzing the diversity of life on Earth.
• An organism’s fitness describes how well it is adapted to its
environment. The environment is made of biotic and abiotic factors.
Which do you think affect’s an organism’s survival and reproductive
success (biotic or abiotic????) and why.
• Section 5.1 packet
Endangered Species Research Report
The following information needs to be included in your document:
1. The common name and the Genus species of your endangered animal.
2. The habitat of your animal (where it lives – you could also include a “subhabitat” like Central Florida or a specific preserve)
3. What is its niche? (How does your animal get food, how it mates, how it
takes care of its young, what are its predators, etc.)
4. Special adaptations this species has for survival.
5. Explain why this species is endangered.
6. What steps are being taken to protect this species.
7. Be sure to include why it is important that it not become extinct.
Above all, be interesting, creative and informative!!!
7.3 Protecting Biodiversity
• Endangered Species Act (ESA) – 1973 – U. S. law
that forbids the gov’t & private citizens from
harming listed endangered & threatened species or
their habitats, forbids trade in products made from
species that are on the list, and it requires the U.S.
Fish and Wildlife Service to maintain the official list
of endangered and threated organisms and to
develop recovery plans for each protected species.
• The goal of the law is to prevent extinctions by
protecting at-risk species from natural and artificial
threats.
Benefits & Costs of the ESA
• Successes: peregrine falcon, brown pelican,
bald eagle
• Roughly 40% of once-declining populations
are now stable
• Costs: protecting the northern spotted owl
in the Pacific NW meant protecting large
areas of old-growth forest and resulted in
many loggers losing their jobs
CITES
• 1975 Convention on International Trade in
Endangered Species of Wild Fauna & Flora
• CITES protects endangered species by banning
international transport of their body parts
• Effective when enforced by the 175 member
nations
• Treaties are agreements under international
laws that rely on enforcement
• Worldwide ban on ivory helped save the
elephants from poaching as there was no market
left
Single Species Approach
• Captive breeding – process of breeding & raising
organisms in controlled conditions (ex. Zoos,
aquariums, botanical gardens)
• Species Survival Plan (SSP) – includes captive breeding
as part of the overall plan to protect a species, and may
include reintroduction back into the wild, education,
outreach and research
• Zoos & aquariums currently oversee SSPs for 180
species
• One SSP success story is the golden lion tamarin, a
primate native to the coastal forests of Brazil
• Cloning – only works if there is ample habitat &
protection in the wild.
Ecosystem & Habitat Approaches
• Managing whole ecosystems protect many species at once.
• Biodiversity hotspots – are areas that both supports an
especially high # of endemic species and is rapidly losing
biodiversity
• Endemic species – found nowhere else in the world
• To qualify as a hotspot, an area must harbor at least 1500
endemic plant species and have already lost 70% of its
habitat as a result of human activity
• Hotspots are seen as areas critical to global diversity
• By mapping these hotspots, we can identify the areas most
in need and focus our resources on them
• Conservation International maintains a list of hotspots
Economic Approaches
• These projects protect wildlife as well as bringing in
money for research and ecotourists.
• Debt-for-nature swap – conservation organizations raise
money and then offer to pay off a portion of a developing
nation’s international debt in exchange for that nation to
promise to set aside reserves, fund education and better
manage protected areas.
• Conservation concession – Conservation International has
started paying countries for the right to conserve their
resources v.s. extracting them instead of that country
selling concessions or rights to corporations to extract
resources.
Wildlife Corridors
• Corridors that connect habitat fragments
• Population sizes often decline when habitats are
fragmented, so establishing corridors will help connect
the fragmented habitats and increase biodiversity
• Exs. – Panthera Foundation’s SE Asia tiger habitat,
Australian Rainforest Foundation’s “Operation Big Bird”
• Locally: wildlife bridges on SR 46 in Lake county, as well
as future bridges within the beltway expansion
7.3 Review
1. What are the major benefits and costs of the Endangered
Species Act?
2. In what ways has the golden lion tamarin SSP been successful?
3. What do the hotspot mapping project, conservation concession
programs, and wildlife corridors have in common?
4. Section 7.3 review packet