Animal Populations What is a population of animals

Animal Populations

What is a population of animals? �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).

Animal Population Characteristics � 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

Dispersion

Dispersion What is an example of clumping?

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

Dispersion Territorial Birds Prairie Dogs Nesting Seabirds

Types of factors influencing population �Abiotic Factors: _____ �Biotic Factors: ______

Types of factors influencing population �Abiotic Factors: Non-Living �Biotic Factors: Living

What Limits Population Growth? Abiotic (Increase) � Optimal light Abiotic (Decrease) � Too much / little light � Optimal temperature � Too low / high � Optimal nutrients temperature � Too low nutrients

What Limits Population Growth? Biotic (Increase) � High Reproductive Rate Biotic (Decrease) � Low Reproductive Rate � Generalized Niche � Specialized Niche � Adequate food supply � Inadequate food supply � Optimal habitat � Degraded habitat

Biotic Increase Continued � Ability to compete for resources Biotic Decrease Cont’d � Unable to compete for resources � Ability to avoid predators � Inability to avoid predators � Ability to resist diseases � Inability to resist diseases � Ability to migrate � Inability to migrate � Ability to adapt to � 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 & N 0 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.

Growth of bacteria �http: //www. youtube. com/watch? v=g. Ewz. Dydci. Wc �What are the reasons why the bacteria won’t go on reproducing and eventually take over the world. �Limiting Factors Density Dependent Density Independent

Density-dependent �competition �water-quality �predation �living space �parasitism/ disease

Density-Independent �Effects not influenced by populations size � Temperature � Storms � Floods � Drought

Survivorship �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 patterns � Type 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)

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

How do Scientist know how many animals are in a population? �Population Sampling: �Transect �Random �Tagging 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?

Tagging Organisms �# of Marked Recaptured = Total Captured Total Marked Total Population This is what field researchers are trying to find Capture, Mark, & Recapture Lab

Random �Randomly selected areas are counted instead of the �entire area �Make a GRID �Count the total number of squares in the grid �Choose 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.

Transect �Make a “T” on a graph Count this box twice!!!

Population Sampling Lab �Population Sampling Lab packet is due tomorrow �Which method is the most accurate?

Deer Tagging in Wisconsin �For tomorrow…… �Find on Article on tagging animals in the wild

Preserving Habitats & Ecosystems �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”

Recovery and Habitat Conservation Plans �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 tradeoffs or cooperative agreements �International Union for the Conservation of Nature and Natural Resources (IUCN)

IUCN �One development of the IUCN was the Convention of International Trade in Endangered Species � This 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

Reintroduction of Wolves in Yellowstone �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

Humans causing extinctions � Habitat Destruction and Fragmentation � In Florida, the panther is one of the most endangered species in North America � Invasive Exotic Species � Polynesian rats on Easter Island � Can you think of anymore around here? � Harvesting, Hunting, & Poaching � The African Elephant � Whaling (Discovery Channel) 7 out of 13 http: //www. youtube. com/watch? v=v. Hq. IOOajg. Fw&feature=channel � Pollution � The Bald Eagle becoming endangered because of the pesticide DDT