animal populations

Animal Populations

Population: _____________

What is a population of animals?

Population: group of individuals from the same species that live in the same area at the same time (that are capable of interbreeding and producing fertile offspring).

What is a population of animals?

Size:

Density:

Dispersion:

Age distribution

Animal Population Characteristics

Size: number of individuals

Density: the number of individuals per unit area or volume.

Dispersion: pattern of spacing among animals within geographic population boundaries.

clumped even random

Age distribution

Animal Population Characteristics

Dispersion

Dispersion

What is an example of clumping?

Dispersion

Can you think of animals who exhibit this type of population behaviors?

Dispersion

Territorial BirdsPrairie DogsNesting Seabirds

Abiotic Factors: __________

Biotic Factors: ___________

Types of factors influencing population

Abiotic Factors: Non-Living

Biotic Factors: Living

Types of factors influencing population

What Limits Population Growth?

Abiotic (Increase)Optimal light

Optimal temperature

Optimal nutrients

Abiotic (Decrease)Too much / little

light

Too low / high temperature

Too low nutrients

What Limits Population Growth?Biotic (Increase)High Reproductive

Rate

Generalized Niche

Adequate food supply

Optimal habitat

Biotic (Decrease)Low Reproductive

Rate

Specialized Niche

Inadequate food supply

Degraded habitat

Biotic Increase Continued

Ability to compete for resources

Ability to avoid predators

Ability to resist diseases

Ability to migrate

Ability to adapt to environmental change

Biotic Decrease Cont’d

Unable to compete for resources

Inability to avoid predators

Inability to resist diseases

Inability to migrate

Inability to adapt to environmental change

EXPONENTIAL GROWTH

Growth in which the rate of growth in each generation is a multiple of the previous generation

Where r is the intrinsic rate of growth& N0 is the initial population

EXPONENTIAL GROWTH

Where r is the intrinsic rate of population growth

r = (gaining)-(losing)Can be positive,

negative, or zero

r = (births + immigrations) - (deaths + emigrations)

Calculate r ?

Calculate r ?R= (gaining) – (losing)2 births + 2 Immigrates-

2 Emigrates + 1 Death

= r= 1

LOGISTIC GROWTH

Carrying capacity (K): the maximum

population size that a particular environment can support.

http://www.youtube.com/watch?v=gEwzDydciWc

What are the reasons why the bacteria won’t go on reproducing and eventually take over the world.

Limiting FactorsDensity DependentDensity Independent

Growth of bacteria

competition water-qualitypredation living spaceparasitism/ disease

Density-dependent

Effects not influenced by populations sizeTemperatureStormsFloodsDrought

Density-Independent

Refers to the number of survivors of a population after a given period of time - just like the TV show! Life tables are used to summarize patterns of life and death; follows a cohort of individuals.  If we plot % survivors vs. time there are three basic patternsType I: most individuals reach physiological age,

little infant mortality, lot of maternal care (e.g., humans)

Type II: constant mortality (e.g., many animals)Type III: high infant mortality, little maternal care

(e.g., many invertebrates, fish)

Survivorship

What does this graph tell us?

Snowshoe hares are preyed upon by lynx. Both species show pronounced population cycles. The cycles are roughly synchronized, although the rise and fall of lynx populations slightly lags the rise and fall of hare populations

Population Sampling:TransectRandomTagging

How do Scientist know how many animals are in a population?

1. What are the pros and cons to using each of these types of sample counting?

2. What are types of organisms that could be used in each of these counts?

3. Can you use actual counting techniques for some of these populations?

# of Marked Recaptured = Total Marked Total Captured Total Population

Tagging Organisms

This is what field researchers are trying to find

Capture, Mark, & Recapture Lab

Randomly selected areas are counted instead of the

entire area

Make a GRIDCount the total number of squares in

the gridChoose one square of the grid at

random.Count the population in that one

square.Estimate the total population by

multiplying the number in one square time the total squares in the grid.

Random

Make a “T” on a graph

Transect

Count this box twice!!!

Population Sampling Lab packet is due tomorrow

Which method is the most accurate?

Population Sampling Lab

For tomorrow……

Find on Article on tagging animals in the wild

Deer Tagging in Wisconsin

Conservation Strategies focus in on saving an entire ecosystem rather than individual species

In 1973, the U.S. Congress passed the Endangered Species Act (ESA)

Designed to protect plant and animals species in danger of extinction against humans or government projects

The U.S. Fish and Wildlife Service (USFWS) identified 2269 species that were listed as endangered or threatened

Maybe hard for a species to be classified as “endangered”

Preserving Habitats & Ecosystems

Under the ESA, the USFWS must prepare a species recovery plan for each listed species.

Concerns from land owners, real-estate developers, and farmers

One compromise to these situations is a habitat conservation plan

A plan that attempts to protect one or more species across large areas of land through trade-offs or cooperative agreements

International Union for the Conservation of Nature and Natural Resources (IUCN)

Recovery and HabitatConservation Plans

One development of the IUCN was the Convention of International Trade in Endangered SpeciesThis was an attempt to stop the slaughter of

African elephants. CITES made the trade of ivory illegal and thus

decreased the amount of poaching and the population of the African Elephant has began to recover

IUCN

Reintroduction: placing a species into a environment that once was able to sustain

Endangered Species: a species that is likely to become extinct if protective measures are not taken immediately

Threatened Species: a species that is likely to become endangered if no measures are taken

Reintroduction of Wolves in Yellowstone

Habitat Destruction and FragmentationIn Florida, the panther is one of the most endangered

species in North America Invasive Exotic Species

Polynesian rats on Easter IslandCan you think of anymore around here?

Harvesting, Hunting, & PoachingThe African ElephantWhaling (Discovery Channel) 7 out of 13

http://www.youtube.com/watch?v=vHqIOOajgFw&feature=channel

PollutionThe Bald Eagle becoming endangered because of the

pesticide DDT

Humans causing extinctions