GE ELECT 4 - midterms (POINTERS ONLY) Flashcards
1
Q
means the surrounding external conditions influencing development or growth of people, animal or plants; living or working conditions, etc. (Singh, 2006)
* living & non-living
* our built environment
* social relationships and institutions
A
Environment
2
Q
understanding the environment
A
lithosphere - solid earth
atmosphere - gases (air)
hydrosphere - all water
biosphere - all life
3
Q
: The rigid outermost shell of a planet. On Earth, it comprises the crust and the uppermost part of the mantle.
A
Lithosphere
4
Q
: The layer of gases surrounding a planet or other celestial body, held in place by gravity. Earth’s atmosphere is primarily composed of nitrogen and oxygen, with smaller amounts of other gases.
A
Atmosphere
5
Q
: The total amount of water on a planet. On Earth, this includes water in oceans, seas, lakes, rivers, groundwater, ice, and water vapor in the atmosphere.
A
Hydrosphere
6
Q
: The part of Earth’s system where life exists. It includes portions of the lithosphere, atmosphere, and hydrosphere.
A
Biosphere
7
Q
- Is define as the
interdisciplinary study of humanity’s relationshipwith other organisms and the nonliving physical environment. - It is the academic field that takes physical, biological, and chemical sciences to study the environment and discover solutions to environmental problems.
A
Environmental Science
8
Q
and the issues that it studies are complex and interdisciplinary.
Includes concepts and ideas from
multiple fields of study.
Decisions have impacts in all these
fields of study.
A
Environmental science
9
Q
Drawing a Bridge of Info
Envi Science
A
- A community decides to use coal for electricity, as it is the cheapest source available. (Economics)
- The coal must be mined from under the soil. (Geology)
- The coal must be transported to the population center by road or rail. (Engineering)
- When it is burned at a power plant, air pollution is released. Some of that pollution is converted to acid in the atmosphere. (Chemistry)
- This falls as acid rain somewhere downwind. (Meteorology)
- The acid stresses plants by affecting their nutrient absorption. (Ecology)
- Laws are passed requiring the plant to install pollution scrubbers. (Politics)
10
Q
Why study envi science?
A
- We depend on our environment
- Environmental Science is our modern way of seeking answers to the questions
- Our environment improves the quality of our lives
- Environmental science teaches us how to protect our environment in the face of rising human population and anthropogenic activities that degrade natural resources and ecosystems.
11
Q
is the discipline that studies the moral relationship of human beings to the environment.
- What is the value of the environment?
- What moral responsibility do we have in dealing with the major environmental problems that result from our resource consumption?
- Which needs should be given the highest priority in our decision
making?
A
Environmental ethics
12
Q
It is the view or belief that human beings are superior to all other organisms
- This set of ethics protects and promotes of human interests or well-being at the expense of all other factors.
- often places an emphasis on short-term benefits while disregarding long-term consequences
A
anthropocentrism
13
Q
It is a perspective that places importance on the ecosystem as a whole.
The preservation of ecosystems or other living things takes priority over human needs.
A
ecocentrism
14
Q
The debate about whether to build a dam in the Hetch Hetchy valley was one of the first big debates between these two philosophies.
- When the growing city of San Francisco, California proposed building a dam in the Hetch Hetchy Valley to provide a steady water supply, Congress debated whether to make a water resource available or preserve a wilderness between 1908 and 1913.
- The dam was eventually constructed.
- The justification for building it was best stated by Gifford Pinochet, the first man in charge of the U.S. Forest Service.
- “Where conflicting interests must be reconciled, the question shall always be answered from the standpoint of the greatest good of the greatest number in the long run.“
A
hetch hetchy debate
15
Q
The focus of the ____________________________ was to protect open land.
The National Parks system, and the National Forest system were both created during this time.
A
Resources Conservationist
16
Q
-
Silent Spring— Rachiel Carson - pestacides like DDT were having on wildlife
- this began
public awakening to threats of pollution and toxic chemicalsto humans as well as other specie
A
Modern Environmentalism
17
Q
explores issues and problems over the entire world, not just within the local community.
Following the 1970s, environmentalism began to consider issues that affected the entire planet:
* Biodiversity loss
* Food production
* Climate Change
* Human population growth
* Economic inequality between nations
A
Global environmentalism
18
Q
Demographic Divide
Developing vs Developed Countries
A
Developing Countries
1. economically poor
1. less educated
1. higher fertility rates
1. lower standart of living
1. lower rates of consumption
Developed Countries
* economically wealthy
* more educated
* lower fertility rates
* higher standard of living
* higher rates of consumption
19
Q
Four Basic Principles of Envi Science
A
- Systematic principle of envi
- Principle of envi capacity
- Symbiosis principle between human and envi
- entropy principle
20
Q
It is the scientific study of interactions between different organisms and between organisms and their environment or surroundings
A
ecology
21
Q
Variability among living organisms from all sources including, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part;
* diversity within species, between species and of ecosystems
- Genetic
- Organismal
- ecological
A
Biological Diversity
22
Q
- encompasses the components of the genetic coding that structures organisms and
variation in the genetic make-up of individuals - this is the
raw materialon which evolutionary processes act - the most basic measure of genetic diversity is genome size— the
amount of DNA (deoxyribonucleic acid)in one copy of a species’ chromosomes - humans === 4.5 pg (3.4 billioin bases pairs)
A
genetic diversity
23
Q
measures of organismal diversity thus include some of the most familiar expressions of biodiversity, such as the numbers of species (i.e. species richness).
high species richness === more types of species in one place (a)
a. 3 cats, 2 horses, 9 fishes
b. 100 birds
A
Organismal Diversity
24
Q
Ecological Organization
A
- Species Group of organisms so similar to another that they can breed and produce fertile offspring.
- Population is a group of individuals of a single species living together within a particular geographic area. They interbreed and compete with each other for resources.
- Community Different populations that live together in a defined area.
- Ecosystem A collection of all organisms that live in a particular place together with their nonliving environment.
- Biome A group of ecosystems that have the same climate and similar dominant communities.
- Biosphere The portion of earth that supports life is called the biosphere. The biosphere extends several km up in the atmosphere to the deepest parts of the oceans.
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* Group of organisms so similar to another that they can breed and produce fertile offspring.
**Species**
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* is a group of individuals of a single species living together within a particular geographic area. They interbreed and compete with each other for resources.
**Population**
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* Different populations that live together in a defined area.
**Community**
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* A collection of all organisms that live in a particular place together with their nonliving environment.
**Ecosystem**
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* A group of ecosystems that have the same climate and similar dominant communities.
**Biome**
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* The portion of earth that supports life is called the _______________. The biosphere extends several km up in the atmosphere to the deepest parts of the oceans.
**Biosphere**
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The simplest definition of an __________ is that it is a `community or group of living organisms that live in and interact with each other` in a specific environment (Ecosystem: Definition, Importance, Examples, Human Causes and Effects, 2020)
**ecosystem**
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**Types of Ecosystem**
1. **`NATURAL ECOSYSTEM`**
Totally dependent on **solar radiation** e.g. forests, grasslands, oceans, lakes, rivers, and deserts. They provide food, fuel, fodder, and medicines.
2. **`MANMADE ECOSYSTEM`**
Dependent on **solar energy**-e.g. agricultural fields and aquaculture ponds.
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Totally dependent on **solar radiation** e.g. forests, grasslands, oceans, lakes, rivers, and deserts. They provide food, fuel, fodder, and medicines.
**NATURAL ECOSYSTEM**
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Dependent on **solar energy**-e.g. agricultural fields and aquaculture ponds.
**MANMADE ECOSYSTEM**
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* are the multitude of benefits that nature provides to society.
* make human life possible by, for example, providing nutritious food and clean water, regulating disease and climate, supporting the pollination of crops and soil formation
**Ecosystem services**
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**TYPES OF ECOSYSTEM SERVICES**
* **`Provisioning Services`** - goods that directly benefit people.
* **`Regulating services`**- processes that moderate natural phenomena
* **`Cultural Services`**- a non-material benefit that contributes to people’s intellectual, cultural and social development.
* **`Supporting services`**- indirect or very long-term impacts on people, but underlie other ecosystem services, particularly provisioning services.
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* goods that directly benefit people.
**Provisioning Services**
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* processes that moderate natural phenomena
**Regulating services**
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* a non-material benefit that contributes to people’s intellectual, cultural and social development.
**Cultural Services**
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* indirect or very long-term impacts on people, but underlie other ecosystem services, particularly provisioning services.
**Supporting services**
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**What shapes an ecosystem**
plant community -> habitat -> Ecosystem
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**`Biotic` and `Abiotic factors`** determine the survival and growth of an organism and the productivity of the ecosystem in which an organism lives.
**Biotic** - living
**Abiotic** - non-living
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**`Sunlight`** is the main energy source for life on earth
Also called **`autotrophs`**
Use light or chemical energy to make food
1. Plants
1. Plant-like protists (algae)
1. Bacteria
**Photosynthesis**—`use light energy to convert carbon dioxide and water` into oxygen and carbohydrates
(Remember: 6CO2 +6H2O Light Energy 6O2 +
C6H12O6)
**Chemosynthesis**—performed by bacteria, `use chemical energy to produce carbohydrates`.
**producers**
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—`use light energy to convert carbon dioxide and water` into oxygen and carbohydrates
(Remember: 6CO2 +6H2O Light Energy 6O2 +
C6H12O6)
**Photosynthesis**
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—performed by bacteria, `use chemical energy to produce carbohydrates`.
**Chemosynthesis**
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—one organism captures and feeds on another organism
* **Predator**—one that does the killing
* **Prey**—one that is the food
**Predation**
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Organisms that r**ely on other organisms** for their energy and food supply.
Also called **`heterotrophs`**
**consumers**
48
**Types of Consumers**
* **Herbivores** - obtain energy * by eating only plants.
* **Carnivores** - eat only animals
* **Omnivores** - eat both plants and animals
* **Decomposers** - breaks down dead organic
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- obtain energy by eating only plants.
**Herbivores**
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- eat only animals.
**Carnivores**
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- eat both plants and animals.
**Omnivores**
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- break down dead organic matter.
**Decomposers**
53
Energy flows through an ecosystem in **one direction— from the sun** or inorganic compounds to **autotrophs (producers)** and then to **heterotrophs (consumers)**
**feeding interaction**
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It is a **series of steps** in which **organisms transfer energy by eating and being eaten**
1. Arrows go in the direction of how energy is transferred
2. Start with producer, end with top consumer
**food chain**
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**Types of Food chain**
1. **`Grazing Food Chain`**
The **grazing food chain** starts with **living plants (producers)** being eaten by herbivores, which are then eaten by predators.
2. **`Detritus Food Chain`**
The **detritus food chain** starts with **dead organic matter (detritus)** being broken down by decomposers, which are then consumed by detritivores and predators.
56
The **_________ food chain** starts with **living plants (producers)** being eaten by herbivores, which are then eaten by predators.
**Grazing Food Chain**
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The **_____________ food chain** starts with **dead organic matter (detritus)** being broken down by decomposers, which are then consumed by detritivores and predators.
**Detritus Food Chain**
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is a detailed interconnecting diagram that shows the overall food relationships between organisms in a particular environment. It can be described as a "who eats whom" diagram that shows the complex feeding relationships for a particular ecosystem.
**food web**
59
, also known as a **trophic or ecological pyramid**, is a graphical representation of the energy found within the trophic levels of an ecosystem.
shows relative amount of energy available at each trophic level.
*
* Organisms in a trophic level use the available energy for life processes (such as growth, photosynthesis, cellular respiration, metabolism, etc.) and release some energy as heat.
**Remember:** Every chemical process that happens in your
body releases heat as a byproduct (ex: burning calories).
*
* **Rule of 10**—only about 10% of the available energy within a trophic level is transferred to the next higher trophic level.
**energy pyramid**
60
shows the **flow of energy between various levels**. Producers and consumers make up the __________, which displays all their comparative masses at the same time. To create the ___________, the approximate masses are stacked up according to a well-established hierarchy
**biomass pyramid**
61
The movement of nutrient elements through the various components of an ecosystem is called nutrient cycling. Another name of nutrient cycling is biogeochemical cycles (bio: living organism, geo: rocks, air, and water)
**biogeochemical cycles**
62
The ___________ describes the process in which `carbon atoms continually travel from the atmosphere to the Earth and then back into the atmosphere.`
**steps:**
* Photosynthesis
* Respiration
* Decomposition
* Combustion
**carbon cycle**
63
The _________ refers to the cycle of `nitrogen atoms through the living and non- living systems of Earth.` The nitrogen cycle is vital for life on Earth. Through the cycle, atmospheric nitrogen is converted to a form which plants can incorporate into new proteins.
**Main processes**
1. Nitrogen Fixation
1. Nitrification
1. Assimilation
1. Ammonification
1. Denitrification
**nitrogen cycle**
64
The __________ describes how `water is exchanged` (cycled) through Earth's land, ocean, and atmosphere.
**Process** :
1. Evaporation
1. Condensation
1. Precipitation
**water cycle**
65
is the **circulation of phosphorus** in various forms through nature. Of all the elements recycled in the biosphere, phosphorus is the scarcest and therefore the one most limiting in any given ecological system.
**Phosphorus cycle**
66
is the process by which the mix of species and habitat in an area changes over time. Gradually, these communities replace one another until a “climax community”—like a mature forest—is reached, or until a disturbance, like a fire, occurs.
* **primary** --- limited
* **secondary** --- destruction of habitat = new plant species
**Ecological succession**
67
—when two organisms of the same or different species attempt to use an ecological resource in the same place at the same time. Ex: food, water, shelter
**Competition**
68
—the ecological niche involves both the `place where an organism lives and the roles that an organism has in its habitat.`
**Niche**
69
A given habitat may contain many different species, but each species must have a different niche. Two d**ifferent species cannot occupy the same niche in the same place** for very long. This is known as the ____________.
**competitive exclusion principle**
70
the process where the Sun's energy is converted into chemical energy (glucose/sugar)
occur in plants
on land, major producers are green plants - contain chlorophyll, which captures light energy
**photosynthesis**
71
```
```Another aspect of a species‘ niche is its _______. It is the `physical environment` in which a species lives and to which it is adapted.
**habitat**
72
—any relationship in which two species live closely together.
**Symbiosis**
73
**SYMBIOSIS TYPES**
1. **Mutualism** - both species benefit (`WIN-WIN`)
eg. *insects & flowers*
2. **Commensalism** - one member of the association benefits and the other is neither helped nor harmed (`WIN-0`)
eg. *barnacles on a whale*
3. **Parasitism** - one organism lives on/inside another organism(host) and harms it by obtaining all/part of its nutrions (`WIN-LOSE`)
eg. *fleas on a dog*
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- both species benefit (`WIN-WIN`)
eg. *insects & flowers*
**Mutualism**
75
- one member of the association benefits and the other is neither helped nor harmed (`WIN-0`)
eg. *barnacles on a whale*
**Commensalism**
76
- one organism lives on/inside another organism(host) and harms it by obtaining all/part of its nutrions (`WIN-LOSE`)
eg. *fleas on a dog*
**Parasitism**
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**photosynthesis formula**
CO2 + H2O -----(LIghtEnergy)--->>> sugar + oxygen
78
**INDUSTRIAL REVOLUTION**
What happens during the Industrial Revolution?
1. **Energy**: coal and steam replace wind, water, human and animal labor.
1. **Organization**: factories over cottage industries
1. **Rural agriculture** declines, urban manufacturing increases
1. **Transportation**: trains, automobiles replace animals, watercraft
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The effects of Industrial Revolution cannot be understated. It changed how and where people lived as well as their environments.
People could no longer get work in rural areas and were forced to move to cities to find work in factories.
Many working class women joined the workforce to support their families.
Rapid urbanization resulted in dirty, crowded cities with poor sanitation that encouraged the spread of disease.
Skilled workers, such as weavers, were replaced by machines that could do the work faster.
New inventions allowed for mass production of goods like cloth.
Factory conditions were poor; work was often dangerous, and pay was often low. Factory owners became rich, while the poor working class struggled to make enough money for basic necessities.
Environmental pollution increased.
**EFFECTS OF INDUSTRIAL REVOLUTION**
80
* The change from a `farming economy to a machine economy`. The "modernizing" of a place.
* is a transformation away from an agricultural- or resource-based economy, toward an economy based on mechanized manufacturing.
* is usually associated with a `greater average income and improved living standards`.
**Industrialization**
81
* `Making products` with employees `as quickly as possible`.
* The system of manufacturing that began in the 18th century with the development of the power loom and the steam engine and is based on concentration of industry into large establishments.
**FACTORY SYSTEM**
82
**WHY DID INDUSTRIALIZATION BEGIN IN ENGLAND FIRST?**
1. **Markets**: England had many overseas colonies (markets)
2. **Population**:
skilled workers
wealthy entrepreneurs
vast number of laborers (workers)
3. **Agricultural Changes**:
Enclosure Acts tenant farmers forced off the farms; moved to cities (urban areas) to find work in factories.
4. **Natural Resources**:
coal, iron ore
good harbors, canals
colonies had raw materials - lumber, cotton
5. **Government**:
stable & unified country; Parliament; Limited Monarchy
fair taxes & solid banking system
6. **Other Factors**:
Island - isolated; had not been through devastating wars
capitalist economy
encouraged science and research
83
pitted the young United States in a war against Great Britain, from whom the American colonies had won their independence in 1783.
When the British interfered with American trade, the Americans had to create their own factories instead of relying on Europe
**The War of 1812**
84
**HOW DID INDUSTRIALIZATION LEAD TO POLLUTION?**
These factors led to the de`pletion of natural resources. `Factories would spew smog and soot into the air and release pollutants and chemicals directly into rivers and streams, resulting in increased air and water pollution. The Industrial Revolution saw an increased use of fossil fuels, including coal.
* Early factories polluted a lot.
* Cities in the 1800s were incredibly polluted.
* Living conditions were usually very bad.
85
, `lethal SMOG that covered the city of London for five days` (December 5–9) in 1952, caused by a combination of industrial pollution and high-pressure weather conditions.
**Great Smog of London**
86
`Emission of carbon dioxide, methane and other waste products` that pollute the air and are believed to contribute to global climate change. Global cement industry contribute 5% of global carbon dioxide emission.
**CONSTRUCTION INDUSTRY**
87
This results in a large amount of hazardous household waste that is often irresponsibly discarded in trash. **When electronics are not recycled properly**, the raw materials them `leech toxic chemicals` into the ground, spoiling both water and food supply *for decades, at least*.
**ELECTRONICS INDUSTRY**
88
Climate changes across the `global fertilizers consists of substances and chemicals like methane, carbon dioxide, ammonia and nitrogen`, the emission of which has contributed to a great extent in the quantity of greenhouse gases present in the environment.
This in turn is leading to global warming and weather changes.
**CHEMICALS INDUSTRY**
89
During the production of textiles a large amount of energy is used to power the factories. This then creates more pollution such as carbon dioxide.
`Dyeing, bleaching or adding finishes to fabrics` often involve using highly toxic chemicals. Water used in process is pumped into rivers and sewage offering wildlife and humans. Growing raw materials such as cotton requires large amounts of pesticides. These pesticides are harmful and often affect birds, the water system and insects.
**TEXTILES INDUSTRY**
90
Water pollution, Loss of Biodiversity, Soil erosion and pollution, Formation of sink holes.
**MINING INDUSTRY**
91
Food accounts for over a quarter (26%) of global gas emissions.
Half of the world's habitable (ice and desert free) land is used for agriculture.
**FOOD AND BEVERAGE INDUSTRY**
92
**HOW DID INDUSTRIALIZATION LEAD TO URBANIZATION?**
People started to `move close to their factory jobs`. This movement led to bigger cities. Urbanization is `an effect of Industrialization`.
**Industrialization** is the process that takes an `agricultural economy and transforms it into a manufacturing one`. Mass production and assembly lines replace manual and specialized laborers. The process has historically led to urbanization by creating economic growth and job opportunities that draw people to cities.
93
is the process through which `cities grow`, and higher and higher percentages of the population comes to live in the city.
**Urbanization**
94
* is the `region surrounding a city`.
* Most inhabitants of urban areas have nonagricultural jobs.
* are very developed, meaning there is a density of human structures such as houses, commercial buildings, roads, bridges, and railways.
* can refer to towns, cities, and suburbs.
**urban area**
95
**URBAN vs RURAL**
**Urban**
* High Population Density
* More than 2500 people
* City
**Rural**
* Low Population Density
* Less than 2500 people
* Countryside
* Agricultural
96
- is defined as the `rate` at which the population of an `urban area increases`. This result from urbanization which is the movement of people from rural areas to urban areas.
**Urban Growth**
97
- can be defined as `urban development with low-density housing`, both residential and commercial, segregated land-use, high level of automobile use combined with lack of public transport, which is in high demand for land (Johnson, 2001).
**Urban Sprawl**
98
- is a place where `people live just outside of a city or town`. There are lots of houses in suburban areas, but not as many other buildings as urban areas—maybe just one or two small shops or stores.
**Suburb**
99
**PULL vs PUSH FACTORS**
**Pull factors** – better jobs, cheaper housing, more resources, better education.
**Push factors** – poor education, medical, religious, cultural
100
An occurs when a `city experiences much warmer temperatures` than nearby rural areas. The difference in temperature between urban and less-developed rural areas has to do with how well the surfaces in each environment absorb and hold heat.
- occurs when a city experiences much warmer temperatures than nearby rural areas.
**urban heat island**
101
**IMPACTS OF URBANIZATION**
**Air Quality**- Human activities release a wide range of emissions into the environment including carbon dioxide, carbon monoxide, ozone, sulfur oxides, nitrogen oxides, lead, and many other pollutants.
**Changes in Patterns of Precipitation**- Cities often receive more rain than the surrounding countryside since dust can provoke the condensation of water vapor into rain droplets.
**Pollution** - Pollutants are often dispersed across cities or concentrated in industrial areas or waste sites. Lead- based paint used on roads and highways and on buildings is one such example of a widely dispersed pollutant that found its way into soil.
**Erosion and other changes in land quality**- Rapid development can result in very high levels of erosion and sedimentation in river channels.
**Degraded Water Quality**- The water quality has degraded with time due to urbanization that ultimately leads to increased sedimentation there by also increasing the pollutant in run-off.
**Flow of Water through Streams** - Higher, faster peak flows change streams channels that have evolved over centuries under natural conditions. Flooding can be a major problem as cities grow and stream channels attempt to keep up with these changes.
**Destruction of Habitats**- There is also complete eradication of habitats as an outcome of urbanization and native species are pushed out of cities.
**Creation of New Habitats**- New habitats are also created for some native and non-native species. Cities also create habitats for some species considered pests, such as pigeons, sparrows, rats, mice, flies and mosquitoes. Urbanization has, for example, eliminated many bat colonies in caves, but has provided sites such as bridges for these species to nest.
102
(moving into the place/country) is the `movement of individuals` **into** `a population from other areas`.
Immigrants contribute to population growth because of both their own numbers and their above-average fertility. Most of those who immigrate are working-age adults.
**Immigration**
103
(exiting from a place/country) is the` movement of individuals` **out** `of a population`.
A number of factors, such as running away from war, searching and finding good education, pursuing a career, searching new jobs or union with family members, results in emigration.
When an individual emigrates from a nation, its population declines gradually.
**Emigration**
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`attract people towards a certain place/country`. Example of pull factors include; better job opportunities, social securities, better health facilities and improved education systems etc.
**Pull factors**
105
`force people to leave the place/country`. Examples of push factors include; lack of social harmony and peace, increased conflict, war, poor education systems, poor job opportunities, lack of adequate resources etc.
**Push factors**
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- An estimate of the `average number of children` that each `woman` in a population `will bear` throughout her childbearing years.
**Total fertility rate (TFR)**
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- The `total fertility rate required to offset the average number of deaths` in a population in order to maintain the current population size.
* tends to be higher in developing countries because mortality among young people tends to be higher.
**Replacement-level fertility**
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- The average `number of years that an infant born in a particular year` in a particular country can be expected to live, given the current average life span and death rate in that country.
**Life expectancy**
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- The `number of deaths of children` **under 1 year** of age per 1,000 live births.
**Infant mortality**
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- The `number of deaths of children` **under age 5** per 1,000 live births.
**Child mortality**
111
- A visual representation of the `number of individuals within specific age groups` for a country, typically expressed for males and females.
- describe how populations are distributes across age ranges
**Age structure diagram**
112
- An age structure diagram that is widest at the bottom and smallest at the top, typical of developing countries.
**Population pyramid**
113
- Continued population growth after growth reduction measures have been implemented.
**Population momentum**
114
occurs in a population that has `many young people and a high death rate at each age`�and therefore a high birth rate, characteristic of a rapidly growing population and also of a population with a relatively short average lifetime.
**The pyramid age structure**
115
occurs where the `birth rate and death rate are low` and a `high percentage` of the population is `elderly.`
**A column shape**
116
occurs if `some event in the past caused a high birth rate or death rate` for some age group but not others.
**A bulge**
117
occurs when a population has `more older than younger people`.
**An inverted pyramid**
118
- studied human population growth and said was growing faster than Earth�s resources
**Thomas Malthus (late 1700�s)**
119
Malthus examined the `relationship between population growth and resources` in one of his works. He then proposed the Malthusian theory of population where he said that the population grows exponentially and the food supply grows arithmetically and that a balance between the two can be established through positive and preventive checks.
**MALTHUSIAN THEORY OF POPULATION**
120
**HUMAN IMPACTS ON ECOSYSTEM**
Modern scientists use there o`bservations and predictions when describing ecosystem�s carrying capacity`
Current human population is about 7 billion.
Not sure what the limit (carrying capacity) is for size of human population.
121
Maximum number of individuals an ecosystem can support
**Carrying Capacity**
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include `coal, natural gas, oil, and nuclear energy`. Once these resources are used up, they `cannot be replaced`, which is a major problem for humanity as we are currently dependent on them to supply most of our energy needs.
**Non-renewable resources**
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- resources that can be used up or `can replenish themselves over time` (e.g. wind energy, solar, lumber, etc.)
**Renewable resources**
