NAME_______________________________________________ PERIOD______ DATE___________
UNIT 4 - ANIMAL POPULATIONS
4.1 POPULATION DYANAMICS
Population dynamics describes constant changes in:
1. Size
• increased growth comes from _____________ and _____________________;
• decreases come from _______________ and ______________________
• Carrying Capacity - It is the maximum population that a habitat can
support over a given time period.
• Size is limited by availability of _________________ and __________________
• Population growth slows as K is reached.
• Technological, social and other cultural changes have extended human’s
range - but how long will it last?
• S-Curve Growtheither indicate growth with fluctuations above and below K, or
_______________ growth where the rate changes as the population increases.
• J-Curve Growthindicate ____________________________ where populations overshoot resources
and crash; also called irruptive; has random spikes and crashes.
 The problem is that early growth curves may look like S when they are
actually J.
• Populations are limited in their capacity for growth in two ways:
a. R-strategists: (R=reproductive potential)
These species have _____________________________________________________
___________________________________________________________________________
ex: rodents, insects
b. K-strategists: (K= carrying capacity)
These species have _____________________________________________________
___________________________________________________________________________
ex: large mammals
2. Density
o _____________________________________________________________________________
o Dense populations tend to have ________________________________ and
_______________________________________ However, this tends to bring high
populations back down. There is controversy over whether
predators actually control the density of the prey, or vice versa.
• Density independent factors are __________________, natural disaster
and _________________________________.
• Density dependent facts are _______________________, migration,
_______________________________ and symbiosis.
3. Dispersion - uniform or random distribution, or clumping of populations
due to availability of resources or niches
4. Age distribution is based on how many individuals are reproductive and
how long they stay that way. Show in survivorship curves or age
structure histograms.
• A survivorship curve indicates trends in populations related to the
number of individuals at each age
a. late loss - living long after reproductive age. ex: ________________
b. constant loss - deaths are about equal at all ages. ex: ____________
c. early loss - fish have short life cycles, but are reproductive most
of their life
4.2 NATURAL SELECTION
1. Populations change because of adaptations to
________________________________________
________________________________________
________________________________________
2. Speciation is the formation of new species from an older species.
3. Speciation - extinction = biodiversity.
4. 3 kinds of Adaptations:
Morphological - specialized structures for habitat, camouflage
ex: _____________________________________________
Physiological - specialized functions. ex: ____________________________
Behavioral - migration, mimicry like these wings with “eyes”
Hardy-Weinberg Law of Population Genetics.
The Law lists criteria that would have to happen for the gene pool
NOT to change.
1. Mating would have to be random.
2. There could be no mutations.
3. There could be no immigration (entering) or emigration (exiting)
an ecosystem so the number of genes remained constant.
4. Populations would have to be large because the Law of
Probability is more accurate when the sample is large.
• Since all of these criteria can never be met, change will occur.
New species arise from:
1. ______________________________ - a small group separated from the main
population will rotate only a few genes. ex: a canyon separates squirrels
and a new specie develops
2. ______________________________ - some birds show a preference for particular
colors, dances or displays.
– ex: ___________________________
4. __________________________ - species move out of home range like the finches
5. __________________________ - different species in same habitat develop similar
characteristics.
– ex: ___________________________
5. ___________________ - adaptations based on dependence to another organism.
– ex. ___________________________
Natural Selection
Results when individuals best suited to the environment are able to survive.
3 types of natural selection:
1. Directional selection
entire population moves toward an extreme
ex: __________________________________________________________________
2. Stabilizing selection
survival favors being average
ex: large mice may need too much food, and have trouble hiding; tiny
mice may be too weak to find food - being average-sized might be better
3. Diversifying selection –
extremes are better able to adapt
ex: _____________________ moths did not blend with the environment;
_____________and ______________ moths had an advantage during the
Industrial Revolution because they ______________________________
Mutations are random genetic accidents; may be beneficial or harmful but
they change the population’s characteristics.
4.3 AMPHIBIANS
AMPHIBIANS & THE ENVIRONMENT
1. _______________________ are an __________________________ who have survived for
350 million years.
2. This long history indicates their adaptability to environmental changes.
3. Their decline on every continent where they live, suggests _________________
_____________________________________________.
4. Fossil records indicate 10 different Amphibian Orders, whereas today
there are only 3 Orders. Frogs, toads, and salamanders compose two
Orders and the third contains the worm-like caecilians.
5. The most common frog was Rana pipens, the ________________________.
6. Amphibian populations are declining due to: Increased
__________________________ from ozone depletion chemical poisoning from
____________________________________________________________________________
competition from ______________________ and _____________________
7. Humans have altered the environment so that predators and exotics have
access to new habitats and compete with frogs both as predators and for
prey.
8. Class Amphibia is important to ecosystems because they are used for
____________________________ and have commercial value as ________________.
9. Contrary to legends, warts are from viruses - not frogs or toads.
AMPHIBIAN LIFE CYCLE
1. The word Amphibian means _____________________________. They must spend
part of their life in the water and part on land. Generally, the larvae
remain in __________________, while adults live on ________________
2. All Amphibians must return to the water for _____________________. Their egg
has _____________ and is part of a jelly-like mass that must be ________________.
3. The eggs are ___________ on the top half and _______________ on the bottom
half. Larvae have a round, heavy-looking body with a thin tail.
4. As metamorphosis continues, the tail is reabsorbed and hind legs appear.
Front appendages appear shortly before the tadpole becomes an adult.
5. Tadpoles are ________________________.
6. Adults eat _______________ and ______________________________.
GENERAL CHARACTERISTICS OF AMPHIBIANS
1. Moist skin - __________________________________________________________________
2. Two nostrils - connect to the mouth and lead to the lungs
3. Adults use _____________ for respiration, while larval stage has ____________.
4. ______________________________________ and ____________________________________
5. Delicate, bony skeleton
6. hibernate in burrows in cold weather; aestivate to __________________________
___________________________________________________________
7. many are _____________________________
8. life-span between ______________________ for toads
4.4 FATAL SUBTRACTION
IMPORTANCE OF WILD SPECIES
1. Wild species are important for their economic, medical, scientific,
ecological, aesthetic, and recreational value.
2. Wild tropical plants provided ______________ of today’s food crop seeds;
________________ of medicines came from plants that were wild.
3. Bioethics is the right of any species to exist. The average specie lasts
about 4 million years.
4. Background (normal) extinction rate is about 3 species per year.
Currently, it is 1000 times that amount.
CAUSES OF SPECIES DECLINE
1. habitat loss or fragmentation (primary factor)
2. human population growth
3. pest and predator control
4. harvesting wild plants
5. hunting, fishing, poaching
6. for sale to collectors and as exotic pets
7. pollution and related diseases
8. exotics have altered habitat giving other species new advantages
3 LEVELS OF DECLINING POPULATIONS
1. Local Decline - no longer found in one native area but are found
elsewhere in the world.
2. Ecological Decline - specie is present but can’t play its role in the
ecosystem
3. Biological Decline
a. Threatened - declining in numbers
b. Endangered________________________________________________________________
Species need _______________ organisms to maintain evolutionary
potential.
c. Extinct means gone forever - when numbers drop below __________
for animal species and ______________ species for plants the species is
considered extinct because of the problems finding _______________.
Populations are doomed when the ___________________ is greater than
the __________________. These organisms have fallen below their
minimal viable population size. They will become extinct unless
change occurs somewhere.
4.5 ENDANGERED SPECIES
ENDANGERED SPECIES ACT (1973)
1. “Conserve and restore endangered and threatened species and the
ecosystems upon which they depend.”
2. It requires protection for any endangered or threatened species take
precedence over economic concerns.
3. The Department of the Interior, acting through the U.S. Fish and Wildlife
Service (FWS), is responsible for protecting most threatened and
endangered species.
4. The number of endangered and threatened species went from 92 to 963
between 1973 and 1995.
5. Then, from 1995 to 1996, Congress banned any more listings.
6. Only 21 species have recovered enough to be reclassified to threatened
and 11 species have been recovered enough to be removed from the list.
7. However, 40% of the species are stable or improving.
8. The ESA has been unpopular with industry, developers, miners, and
timber ranchers, who contributed nearly $1 million to support repealing
it.
9. However, the ESA has had no negative impact on U.S. economic
development.
10.
Funding costs each adult about 25 cents per year.
The Number of Endangered Species by Vertebrate Class and Most
Affected Specie in Each Group
OTHER TREATIES & LAWS
1. Migratory Bird Treaty Act prevent the destruction of non-game migratory
birds or eggs.
considers some 170 species to be “game birds,” less than 60 species are
typically hunted each year. The most common are
___________________________________________________
2. In 1993, Sec. of the Interior, Bruce Babbitt launched a national biological
survey of wild species.
3. The 1975 CITES Treaty, Convention on International Trade of
Endangered Species, bans commercial trade of an agreed list of
endangered and threatened species.
METHODS OF WILD SPECIES PROTECTION
1. Ecosystem approach - _________________________________________
2. Species approach - _____________________________________________
3. Wildlife management - __________________________________________________________
____________________________________________________________________________________
IMPROVING SURVIVAL ODDS
1. ____________________________________________________________________________________
2. Egg pulling for relocation in a safe place
3. Regulating hunting with __________________ and _________________________________
4. Exclusive economic zones for commercial fishing
5. Protection of migratory bird flyways
6. ________________________________________
7. Zoos currently only house 27 endangered populations of more than 100
individuals, but zoos also create problems:
a. They have limited space for larger populations who need greater
habitat space.
b. Individuals can’t go back home if their habitat is gone.
c. Animals in zoos can’t fulfill their roles in the ecosystem.
4.6 MANATEES
MANATEE FACTS:
1. The Florida Manatee has been protected by state law since 1893 and by
the Endangered Species Act of 1973 - but only about 3000 still survive.
2. Manatees are related to the ______________________________.
There were 5 populations in the Order Sirenia.
a. West Indian Manatee - Trichechus manatus migrates from Brazil to
Florida
b. West African Manatee - coastal, freshwater of ________________________
c. Amazonian Manatee - freshwater in ________________________________
d. Dugong - found in ____________ and __________________, has a different tail
e. Stellar Sea Cow - hunted to extinction within 27 years of its
discovery in 1741 in the Bering Strait
3. The average manatee is _______________ and weighs ___________________.
Calves are around ______________ and weigh ___________________
4. They like warm, shallow water and need ____________________ to drink.
Constant eating helps ________________________________________ of water weeds.
5. In freshwater, they encounter boats where _____________ of their deaths are
from human-related boat accidents.
6. Many manatees are identified by their boat propeller scars.
7. Manatees are ____________________, who eat ___________________________________
____________________or 10 % of their total body weight.
8. They have large lips to _______________________ and replaceable molars.
9. Because they have no predators, no social structure is present - not
territorial. Herds have no leader and no permanent bonds are formed for
mating.
MANATEE’S MAMMALIAN CHARACTERISTICS
1. Whiskers (vibrissae) on the snout are used to ___________________________
2. Mammary glands - cows nurse their young ___________________
3. Live births – the gestation period is _________________. They produce one
calf every _________________ and don’t reach sexual maturity until ___________
4. ____________________________________________________________________________________
5. May live up to __________________________
6. Large brain - __________________________, hearing is primarily in a different
range from humans
7. Compartmentalized, ruminating stomach
8. Breathe air - may dive for 20 minutes
9. Marine mammal tail – __________________________________________
10.
Can produce a high-pitched whistle and clicks for ____________________
4.7 Wildlife Management
WILDLIFE MANAGEMENT OFFICER:
1. ____________________________________________________________________________________
____________________________________________________________________________________
2. These scientists manage the water, space, food and shelter to benefit wild
populations and enhance human enjoyment of them.
3. The manager needs to know the habitat requirement of the managed
species, which can be grouped into 4 areas:
a. Early successional animals - those who require weedy, pioneer
plants in areas that have been disturbed by fire, volcanoes, or
human activity.
b. Mid-successional – Those who benefit from abandoned cropland
and open areas created by farming, logging, road-building activities
that create an edge effect. Edges, called ecotones, provide a
transitional zone for animals such as deer that feed in clearings but
can escape to the forest for cover.
c. Late-successional species - prefer old growth forests and need
larger spaces
d. Wilderness species - need undisturbed areas with mature
vegetation
5. Managers use techniques such as planting seeds, clearing brush, building
artificial nests, and improving ponds to create and restore habitats.
GAME MANAGEMENT & HUNTERS
1. There is conflicting interest in the public between the advantages of
diversity vs. density.
2. Bird-watchers want _________________. Hunters want _____________________.
3. Game animals are 10% of the wild species, but 90% of the money spent
on wildlife goes to this group.
4. Funds for state game management come from the sale of ______________ and
________________ licenses and from _______ on hunting and fishing equipment.
5. There are over 16 million sports hunters in the U.S. who contribute
significant money to support research, and to buy, restore and maintain
wildlife habitats.
6. ____________________________________________________________________________________
____________________________________________________________________________________.
7. Opponents say that wildlife management creates a surplus of game
animals but not predators who present a safety issue for humans and
livestock as well as reducing game species.
8. Thinning populations is then required because we have altered the food
chain.
9. The Migratory Bird Hunting and Conservation Stamp Act (1934)
______________________________________________________________________________ The
revenues are used to buy and manage their habitat.
GAME MANAGEMENT & FISHING
1. The fishing industry also has severe management concerns.
2. Over-fishing has resulted from _________________________________________________
____________________________________________________________________________________
3. Managers have tried to reduce over-fishing by setting quotas, dividing the
allowable catch by the number of commercial boats, and by regulating the
type of fish methods and gear.
4. Exclusive Economic Zone (EEZ)
o The area 200 nautical miles off shore is the Exclusive Economic
Zone (EEZ) of the adjacent country. Foreign fleets are allowed only
by permission.
5.
6.
7.
8.
o However, beyond this legal jurisdiction, usage of the high seas is set
by international laws and treaties.
o Enforcement is very difficult because if one fleet doesn’t take the
maximum catch, someone else will. (Tragedy of the Commons)
Sport-fishing is managed with _________________________________________________
____________________________________________________________________________________
_____________________ and _____________________________ improve inland waters,
but the high seas are much more difficult.
The International Whaling Commission is a good example of managing
whale populations after 8 of the 11 major species were driven to
commercial extinction.
However, compliance is voluntary and whales are no longer available.
The U.S. stopped whaling in 1970.