Chapters 5, 6, 11, 12 Study Guide
Coevolution: Species affecting each other. Interactions between species can cause microevolution.
Changes in the gene pool of one species can cause changes in the gene pool of the other. Adaptation
follows adaptation in something of a long term “arms race” between interacting populations of different
populations which is the Red Queen Effect. Predators and prey evolve in response to one another, so do
parasites and hosts in a process called coevolution. Hosts and parasites will evolve new responses to
the others latest advance (evolutionary arms race)
Biodiversity: refers to the sum total of all organisms in an area taking into account the diversity of
species, their genes, their populations, and communities. Scientists have described between 1.5 million
to 1.8 million species. Tropical rainforests are rich in biodiversity.
-Speciation-Extinction=Biodiversity
-As we grow in population over next 50 years, we are expected to take over more of the earth's surface
and productivity → premature extinction due to humans.
-Species richness increases as one approaches the equator with plant productivity and climate stability
playing key roles. Greater amounts of solar energy, heat, and humidity at tropical latitudes lead to more
plant growth.
-Causes of biodiversity:
1. habitat alteration- Every human changes the habitat around us like farming, grazing, clearing
forests, dams, urbanization, etc.
2. Invasive species- our introduction of non-native species to new environments. An introduced
species may increase rapidly, spread, and displace native species.
3. Pollution- Air pollution degrades forest ecosystems, water pollution can affect fish, agricultural
runoff can harm many species.
4. Over harvesting-For most species, a high intensity of hunting or harvesting by humans will not
in itself pose a threat of extinction, but for some species it can like the Siberian tiger.
-Benefits of biodiversity: provides food, shelter, purifies air and water, stabilizes and moderates Earth's
climate, moderates floods, generates soil fertility, pollinates plants, controls pests and diseases,
enhances food security, economic benefits through tourism and recreation.
Extinction and mass extinctions: Extinctions occur naturally. Mass extinctions have occurred at widely
spaced intervals and wiped out 95% of planet's species. (like the one that ended dinosaurs) The 6th mass
extinction is coming due humans. 99.9% of all the species that have ever lived are now extinct. Mass
extinctions can be due to catastrophic global event, temperature changes, asteroids. → reduces
competition, opens niches to exploitation by new species and leads to adaptive radiation. Each of the
mass extinctions eliminated more than one-fifth of life's families and at least half of its species.
Symbiosis:
Type of interaction
Effect on species 1
Effect on species 2
Mutualism
+
+
Commensalism
+
0
Predation, parasitism, herbivory
+
-
Neutralism
0
0
Amensalism
-
0
Competition
-
-
Predator-prey relationships: Predation is the process by which individuals of one species, a predator
hunts, captures, kills, and consumes individuals of another species, the prey. Predation can sometimes
drive population dynamics by causing cycles in population sizes. An increase in the population size of
prey creates more food for predators, which may survive and reproduce more effectively as a result. As
the predator popl rises, additional predation drives down the popl of prey. Fewer prey in turn causes
some predators to starve so that the predator popl declines. Individual predators that are more adept at
capturing prey will likely live longer, healthier lives, and be better able to provide for their offspring
than will less adept individuals.
Succession (primary and secondary): Its severe enough to eliminate all or most of the species in a
community, the affected site will undergo a somewhat predictable series of changes. Primary
succession follows a disturbance so severe that no vegetation or soil life remains from the community
that occupied the site. In primary succession, a biotic community is built essentially from scratch
usually after a bare expanse of rock, sand, or sediment newly exposed to atmosphere. Secondary
succession begins when a disturbance dramatically alters an existing community but does not destroy
all living things or all organic matter in the soil. Usually begins with a fire, hurricane, logging.
Island Biogeography theory: Explains how the number of species on an island results from an
equilibrium balance between the number added by immigration and the number lost through
extirpation. The farther an island is located from a continent, the fewer species tend to find it and
colonize it. Large islands have higher immigration rates because they present fatter targets. Large
islands have lower extinction rates because more space allows for larger populations. Small islands lose
their diversity faster starting with large species. The equilibrium theory of island biogeography explains
how species come to be distributed among oceanic islands. Researchers have also applied it to habitat
islands-patches of one habitat type isolated within seas of others.
Relevant laws and policies: Endangered Species Act (ESA) forbids the government and private citizens
from taking actions such as developing land that destroy endangered species or their habitats. (US Fish
and Wildlife Service and National Marine Fisheries Service are responsible) But had little success.
-The Lacey Act: aid in restoring game and other birds in parts of US where they are scarce or extinct
and to regulate the inroduction of birds and animals in areas where they had not existed.
Functions of various governmental agencies:
Agency
National Park
Service
U.S. Forest
Service
Fish and
Wildlife
Service
Bureau of
Land
Management
National
Marine
Which
Department
Dep of Interior
Dep of
Agriculture
Focus of Agency (See below)
Protects America’s natural resources, cultural values, honors our cultures,
and tribal communities, and supplies energy to power our future.
Sustain health, diversity, productivity of the nation’s forests and grasslands
to meet the needs of the present and future generations.
Dep of Interior
Working with others to conserve, protect, and enhance, wildlife, plant, for
the continuing benefit for the community.
Dep of Interior
To sustain the health, diversity, and productivity of America’s public lands
for the use and enjoyment of present and future generations
Dep of
Commerce
Responsible for the stewardship and management of the nation’s living
marine resources and their habitat.
Fisheries
Service
U.S.
Geologic
Dep of Interior
al
Survey
Provides reliable scientific information to describe and understand the
Earth; minimize loss of life and property from natural disasters; manage
water; biological, energy, and mineral resources; and enhance and
protect our quality of life.
Endangered Species: So few left that species could soon become extinct over all of most of its range
like bald eagles.
Camouflage, mimicry, other evolutionary adaptations:
Evolution, natural selection, types of selection (disruptive, stabilizing, directional): Evolution is a
regular progression in the complexity of life forms on Earth. Formation of crust and atmosphere →
small organic molecules form → large organic molecules → final protocells form → sing-cell
prokaryotes form → simple cell eukaryote → variety of multicellular organisms form.
-Natural selection is the process by which traits that enhance survival and reproduction are passed on
more frequently to future generations than those that do not, thus altering the genetic makeup of
populations over time. One faces a constant struggle to survive and reproduce, another tends to produce
more offspring that can survive, a third is that individuals of a species vary in their characteristics.
-Directional: selection that drives a feature in one direction rather than another for example. Toward
larger or smaller. Faster or slower.
-Stabilizing: produces intermediate traits, in essence preserving the status quo.
-Disruptive: Traits diverge from their starting condition in two or more directions.
Importance of genetic variation and population size: Sexual reproduction when organisms reproduce
through sex, they mix, or recombine their genetic material. Variable genes and variable environments
interact as organisms engage in a perpetual process of adapting to the changing conditions around
them. It helps to elaborate and diversify traits to the formation of new species/organisms.
-Mutations: accidental changes in DNA and can be passed on to the next generation.
Types of Species (indicator, keystone, generalist, and specialist): Specialists are species with narrow
breadth and very specific requirements. Generalists has broad tolerances able to use a wide array of
habitats or resources. Removal of a keystone species will have substantial ripple effects and will alter a
large portion of the food web.
Native vs non-native species: Adding non-native species will help the economy to run, purify water, for
culture and historical reasons. If we just keep the native species then diseases can spread, there isn't
enough date and information, degrades ecosystem.
Competition (inter/intra specific): When multiple organisms seek the same limited resource. They
usually do not fight with one another directly or physically. Competition is generally more subtle,
involving consequences of one organism's ability to match or outdo others. Intra: competitive
interactions can take place among members of the same species. Inter: among members of two or more
different species.
Ecological/realized/competitive exclusion (niche): A niche are species's ecological roles. The full niche
of a species is called fundamental niche. An individual that plays only part of its role because of
competition is called a realized niche.
Habitat fragmentation: Forest clearing, farming, road building, and other types of human land use and
development can fragment natural habitats. It usually begins when gaps are created within a natural
habitat. As development proceeds, these gaps expand, join together, and eventually dominate the
landscape, stranding islands of habitat in their midst. Fewer populations can persist, and numbers of
species in the fragments decrease with time.
Biogeochemical cycles (nitrogen, sulfur, phosphorus, carbon):
Vectors:
Climate and evolution connection: There are macroevolution (long term large scale evolutionary
changes) and microevolution. (small genetic changes) Animals become adapted to these change.
Reasons populations would be or not be prone to extinction: Narrow geographical ranges (less of a
supportive habitat), only one or a few populations (the fewer population, the greater risk of extinction),
population is too small (less genetic variability and less resistance), low population density (fewer
individuals per unit area), require a large home range, low rates of population increase (delayed
reproduction), specialized niche, hunted or harvested by people, fragmentation.
Biological diversity: Refers to the sum total of all organisms in an area, taking into account the
diversity of species, their genes, their populations, and their communities. 1.5-1.8 million species have
been found but there are about 100 million species on this earth in total. Many are in tropical
rainforests such as Costa Rica's.
Energy acquisition for organisms: Producer, primary, secondary, tertiary, etc. You only gain 10% of the
energy you had from the step below. Plants receive energy from the sun and water and convert it using
the process of photosynthesis. Mammals acquire energy from activities such as eating, drinking and
sleeping.
Reintroduction programs:
National park
service
1916
To oversee
federal lands
from it’s
destruction from
industries in
pursuit of natural
resources
National forest /
grasslands
1905
Land
management
National
Monument
1906
National
monuments would
be proclaimed to
protect prehistorical culture
and or features.
This could be done
without Congress’s
consent and passed
by the President to
reduce time in
between
legislation.
Bureau of land
management
Land
1946
Wildlife refuge
1903
To sustain the
health, diversity
and productivity of
Conserve America’s
the public lands for
fish wildlife and
the use and
plants
enjoyment of
present and future
generations.
Population dynamics (density, immigration, emigration): Immigration are the arrival of individuals
from outside the population. Emigration is the departure of individuals from the population.
Allelic frequency/frequency of traits: The dominate allele will become stronger and stronger through
generations. The recessive allele will lose it's strength. Genetic drift: random change in allele
frequencies over generations brought by chance this leads to genetic diversity.
Sustainable forestry: Sustainable forestry certification examines the practices of timber companies so
that their methods are sustainable. Sustainable forestry is more costly for the timber industry but if
certification standards can be kept strong, then consumer choice in the marketplace can be a powerful
driver for good forestry practices.
Types of isolation: Pre-Zygotic isolation is when mating or zygote formation is blocked due to
temporal isolation, behavioral isolation, mechanical isolation, ecological isolation and gamete
mortality. Post-Zygotic isolation is when hybrids don't work. Zygotic mortality- egg is fertilized but
zygote or embryo dies. Hybrid inviability- first generation hybrid forms but shows low fitness. Hybrid
infertility is when hybrid is fully or partially sterile.
What effects species diversity: HIPPO- Habitat alteration, invasive species (introduction of non-native
species to new environments), population growth, pollution (air pollution, water pollution, agricultural
runoff, oil and chemical spills), over harvesting. (vulnerable species are large, few in number, long
lived, and have few young)