After 100 years of supposed No inhabitance of New York City What are these changes called?

Succession- a series of changes in a community in which new populations of organisms gradually replace existing ones What would happen to the road if no one used it?

Primary succession- colonization of new sites by communities of organisms takes place on bare rock Sources of bare rock: 1. Volcanic lava flow cools and leaves bare rock 2. Glaciers retreat and expose rock

First to colonize: Lichens

What comes next??? Mosses Create humus Retain water Decayed matter that provides nutrients for the soil Retain water

Pioneer Species: the first organisms to colonize a new site Ex: lichens are the first to colonize lava rocks Rock

Climax community- a stable, mature community that undergoes little or no succession

Secondary succession- sequence of community changes that takes place when a community is disrupted by natural disaster or human actions – takes place on existing soil

Secondary succession- Ex: A fire levels portions of a forest A farmer plows his field

Why does Secondary Succession happen faster? Seeds are already in the soil Some plants can re-grow from their stumps, roots Soil still has nutrients & micro organisms in it.

Secondary succession-

What do you think is happening in the pictures?

Pond Succession

Start of Pond Succession 1) seeds are flown in by birds and land animals come to inhabit the pond. These are the pond pioneers. 2) As more creatures arrive the debris on the bottom increases. *Emergent plants have roots under water while part of their bodies resides above the water line.

Slowly the vegetation takes over until….. 3) Emergents then appear on the edges of the pond. Over time, sometimes hundreds of years, as ponds plants grow, die and decompose, layers of debris build up. These layers of decaying matter raise the pond floor over the years. 4) After some time, the pond floor is close enough to the bottom that emergents can grow all the way across the floor.

Review What type of succession is pictured?

Higher Level Thinking What happens as succession increases over time? # of species increases Total population increases Total Biomass increases Organic Matter increases

Which pond is the youngest?

Ecology of Populations 22

Population Growth Populations grow when birth rate exceeds rate of mortality DEATH 23

Population Growth World population now 6.47 billion (Oct 12, 2005) At the present time the current population of the earth is 6.47 billion (October 12, 2005), having reached six billion on 19-Jun-99 at about 5:56:07 AM GMT. For a current estimate, see the Population Clock web page at: http://www.census.gov/main/www/popclock.html World population now 6.47 billion (Oct 12, 2005) Click here for current US and World population estimates -> http://www.census.gov/main/www/popclock.html

Demography is the study of factors that affect the growth and decline of populations Additions occur through birth, and subtractions occur through death. Demography studies the vital statistics that affect population size. Less-developed counties represent 80% of the world population, but more than 90% of projected growth Richer countries tend to have negative growth rates Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Current Birth and Death Rates Every second: about 4 children are born, while about 2 other people die Net gain: 2.3 humans added to the world population every second, 72 million added every year The human population continues to grow rapidly. I am not sure if these statistics put it into perspective, but basically, every second twice as many children are born as people die and the impact of this of this is that 2.3 people are added to the world population every second. There are over 31 million seconds in every year, which means that about 72 million people are added each year.

Parameters that effect size or density of a population: Immigration Birth Population (N) Death Emigration Figure 1. The size of a population is determined by a balance between births, immigration, deaths and emigration

Age Distribution Age-Structure Diagram shows growth patterns of populations grouped into categories Horizontal axis = Number of individuals 28

Human Age Distribution Developed countries Less-developed countries 29

Exponential growth (J-shaped curve)-- Assumes no limitations on resources.

S-shaped curve

KEY FEATURES OF POPULATIONS, con’t Population size is limited by: density-dependent factors Disease Competition Predators Parasites Food Crowding The greater the population, the greater effect these factors have. Ex. Black plague in the Middle Ages – more deaths in cities density-independent factors Volcanic eruptions Temperature Storms Floods Drought Chemical pesticides Major habitat disruption (as in the New Orleans flooding) Most are abiotic factors

Humans are part of the Earth's ecosystem. Human activities can either deliberately or inadvertently alter the balance of an ecosystem.  

How do human activities affect the environment? What do you Think??? How do human activities affect the environment?

Will you change your perspective or will you feel the same way? With more info… Will you change your perspective or will you feel the same way?

Human impacts on the Environment Global warming Use of machinery by humans seems to be increasing CO2 levels in the air. CO2 prevents heat from escaping, causes slight world wide temperature increases Rising water temperatures causes coral bleaching 36

Human impacts on the environment Deforestation Caused by demand for wood products, need for space, farmland, housing, roads Deforestation causes habitat fragmentation Animals and plants are forced into confined areas 37

Habitat Fragmentation

Habitat Fragmentation

Human impacts on the Environment Ozone depletion Caused by aerosol chemicals called chlorofluorocarbons (CFCs) CFC’s Escape into atmosphere, reacts breaking down the ozone (O3, a protective atmospheric layer) UV rays penetrate the atmosphere and cause harm to many organisms 40

“HOLE” in the ozone (O3)

Human impacts on the Environment Fishing activities Demand for fish and shellfish Commercial Fishing be harmful to environment in many ways 42

Human impacts on the environment Invasive species (EXOTIC SPECIES) introduced by people accidentally or intentionally Can cause problems if no natural enemies are present Cane toad was introduced to Australia to control cane beetles, pest insects that destroy sugar cane crops 43

Human impacts on the Environment Exotic pet trade Capture and sell wild animals from exotic locations Wealthy buyers and collectors desire obscure animals Animals removed from their habitat causes an imbalance in the ecosystem 44

Importance of the Environment Biodiversity = Many different types of organisms Organisms depend upon one another Interfering with one Organism can have a Ripple effect to many w/in the habitat 47

Importance of the environment Natural resources: Non-renewable includes fossil fuels (petroleum, coal) Renewable includes animals, plants, water, wind, etc. even renewable resources can run out 48

Importance of the Environment Natural resources Renewable energy sources include wind power, geothermal energy, ocean currents 49

Pollution: Agricultural Homes Industry DDT Fertilizers Animal wastes (nitrogen) Homes Strong cleaning agents Industry Toxic gases and wastes Acid rain

Effects of Human Activities on Water Cycle We alter the water cycle by: Withdrawing large amounts of freshwater. Clearing vegetation and eroding soils. Polluting surface and underground water. Contributing to climate change.

Effects of Human Activities on Carbon Cycle We alter the carbon cycle by adding excess CO2 to the atmosphere through: Burning fossil fuels. Clearing vegetation faster than it is replaced. Figure 3-28

Effects of Human Activities on the Nitrogen Cycle We alter the nitrogen cycle by: Adding gases that contribute to acid rain. Adding nitrous oxide to the atmosphere through farming practices which can warm the atmosphere and deplete ozone. Contaminating ground water from nitrate ions in inorganic fertilizers. Releasing nitrogen into the troposphere through deforestation.

Toxins in food chains- While energy decreases as it moves up the food chain, toxins increase in potency. This is called biological magnification 54

http://www.youtube.com/watch?v=FnDT_6V4qVw&feature=related

What Sustains Life on Earth? Biogeochemical Cycles What Sustains Life on Earth? Solar energy, the cycling of matter, and gravity sustain the earth’s life. Figure 3-7

Two Secrets of Survival: Energy Flow and Matter Recycle An ecosystem survives by a combination of energy flow and matter recycling. Figure 3-14

Water cycle- 58

Carbon Cycle All living things are made of carbon. Carbon is also a part of the ocean, air, and even rocks. Plants use carbon dioxide and sunlight to make their own food and grow. The carbon becomes part of the plant. Plants that die and are buried may turn into fossil fuels made of carbon like coal and oil over millions of years. When humans burn fossil fuels, most of the carbon quickly enters the atmosphere as carbon dioxide

Carbon cycle- 60

Nitrogen cycle- Atmospheric nitrogen (N2) makes up nearly 78%-80% of air. Organisms can not use it in that form. Lightning and bacteria convert nitrogen into usable forms. Only in certain bacteria and industrial technologies can fix nitrogen they are called nitrogen- fixing bacteria- Some live in a symbiotic relationship with plants. Nitrogen fixation-convert atmospheric nitrogen (N2) into ammonium (NH4+) which can be used to make organic compounds like amino acids. 61

Effects of Human Activities on the Nitrogen Cycle Human activities such as production of fertilizers now fix more nitrogen than all natural sources combined. Figure 3-30

Phosphorous Cycle Phosphorous is an essential nutrient for plant and animals. Can be found on earth in water, soil & sediments. Slowest cycle of them all Cycles through plants and animals faster than rocks and sediments

Effects of Human Activities on the Phosphorous Cycle We remove large amounts of phosphate from the earth to make fertilizer. We reduce phosphorous in tropical soils by clearing forests. We add excess phosphates to aquatic systems from runoff of animal wastes and fertilizers.

mining Fertilizer excretion Guano agriculture weathering uptake by autotrophs uptake by autotrophs leaching, runoff Marine Food Webs Dissolved in Ocean Water Dissolved in Soil Water, Lakes, Rivers Land Food Webs death, decomposition death, decomposition Figure 3.31 Natural capital: simplified model of the phosphorus cycle. Phosphorus reservoirs are shown as boxes; processes that change one form of phosphorus to another are shown in unboxed print. QUESTION: What are three ways in which your lifestyle directly or indirectly affects the phosphorus cycle? (From Cecie Starr and Ralph Taggart, Biology: The Unity and Diversity of Life, 9th ed., Belmont, Calif.: Wadsworth © 2001) weathering sedimentation settling out uplifting over geologic time Marine Sediments Rocks Fig. 3-31, p. 77

Toxins in food chains- While energy decreases as it moves up the food chain, toxins increase in potency. This is called biological magnification 68