Environmental Race to save the Planet

Question 1

_________describes the study of the interaction between organisms and their nonliving environment.

Answer 1

Ecology

Question 2

Ecology examines _________ in the natural world.

Answer 2

interactions

Question 3

Ecologists focus on the interactions of organisms, ___________, communities, ecosystems and biospheres.

Answer 3

populations

Question 4

A population relates to an interacting group of the same ________ occupying a particular area at the same time. For example, a group of maple trees in the same forest. Ecologists focus on populations because of their impact on the environment.

Answer 4

species

Question 5

Populations alter their size, age distribution, density and _______ makeup to adapt to changing environmental conditions.

Answer 5

genetic

Question 6

Genetic changes over time may be made in response to a shift in environmental conditions to improve the chances of _______________ of a population.

Answer 6

survivability

Question 7

Organisms are classified into _______, which can be differentiated by the way the way they reproduce

Answer 7

species

Question 8

The two types of reproduction are asexual reproduction and sexual reproduction. The first usually occurs in _________ with only one cell, which splits up to produce clones to replace the original cell. Sexual reproduction requires sex cells from both parents to produce offspring.

Answer 8

bacteria

Question 9

A(n) _________ is a natural or artificially created community of varying species interacting with one another and the nonliving environment.

Answer 9

ecosystem

Question 10

A community describes a place where populations of various ________ live together in the same space and is an intricate network of animals, plants and organisms.

Answer 10

species

Question 11

The _________ describes all of the planet’s ecosystems.

Answer 11

biosphere

Question 12

The Earth’s life-giving system is made up of the atmosphere, ___________, stratosphere, hydrosphere, lithosphere and biosphere.

Answer 12

troposphere

Question 13

The hydrosphere consists of the Earth’s ______ sources, liquid, solid and vapor in the air

Answer 13

water

Question 14

The stratosphere contains sufficient quantities of _____ to filter out the sun’s harmful ultraviolet rays; thereby permitting life on Earth.

Answer 14

ozone

Question 15

The sun plays an important role in sustaining life on Earth in that it provides warmth, light, stimulates ______________, promotes the cycle of matter and determines the climate and weather systems.

Answer 15

photosynthesis

Question 16

The sun promotes the cycling of matter. The Earth is essentially closed off to space and hence all matter on Earth must be _________. This matter includes atoms, ions and molecules that are necessary for living organisms to survive on.

Answer 16

recycled

Question 17

Carbon dioxide (CO2), methane, nitrous oxide and water vapor are all examples of __________ gases.

Answer 17

greenhouse

Question 18

These gases create the natural greenhouse _______ as they assist in the reduction of heat flow back into space. This keeps the Earth warm enough to maintain life.

Answer 18

effect

Question 19

The natural greenhouse effect was first described by ______________ in 1824.

Answer 19

Joseph Fourier

Question 20

The role of water vapor and CO2 was identified later by _________________

Answer 20

Claude Pouille

Question 21

According to the EPA, passenger cars and light trucks account for 17% of all man-made ___ emissions.

Answer 21

CO2

Question 22

Most carbon dioxide (CO2) results from the generation of ___________ power (34%) followed next by industry, which emits 29% of all manmade CO2.

Answer 22

electrical

Question 23

The biosphere can be divided up into biomes and _______ life zones.

Answer 23

aquatic

Question 24

Biomes describes the portion of the biosphere that is covered by _____ and includes the forests, deserts and grasslands that have a particular climate and life forms that have adapted to those conditions.

Answer 24

land

Question 25

Natural ecosystems do not have specific boundaries and are not genuinely self-sustaining because one ecosystem will tend to join up with a neighboring one in a ____________ area known as an ecoton

Answer 25

transitional

Question 26

An ecotone describes an area containing a ________ of species between two or more ecosystems. An example of an ecotone is the marsh or wetland found between dry land and water.

Answer 26

mixture

Question 27

A desert biome is characterized by scattered annual rainfall of less than 25cm or __ inches. and sparse, broadly spaced low vegetation.

Answer 27

10

Question 28

The plant life in the desert ecosystem have _______ by developing waxy leaves to minimize water loss, deeply growing roots to tap into groundwater and becoming dormant in drier periods.

Answer 28

adapted

Question 29

Mosses and ________ tend to do this as a conservation and survival technique.

Answer 29

lichens

Question 30

There are three main types of _________ biomes are the tropical, temperate and tundra.

Answer 30

grassland

Question 31

The tundra or ______ grasslands are concentrated just south of the arctic polar cap. There is little precipitation (which falls as snow), is very cold and windy.

Answer 31

polar

Question 32

________ grasslands are typified by a prolonged dry season, low to medium rainfall and high mean temperatures.

Answer 32

Tropical

Question 33

This is the nature of grasslands and they can be found in a wide belt either side of the ________.

Answer 33

Equator

Question 34

A popular type of grassland biome is called a savanna, which is characterized by a year round ____ climate, two dry seasons and plentiful rainfall the rest of the year.

Answer 34

warm

Question 35

The largest savannas are found in Africa, __________ and South-East Asia.

Answer 35

Australia

Question 36

The _______ tropical savannas are home to large number of grazing and browsing animals who have adapted their eating habits in such a way as not to compete with other animals.

Answer 36

African

Question 37

Grazers eat grass and herbs and _________ eat leaves and shoots. The different animals eat different foods and hence reduce competition. For example, giraffes eat the top leaves and shoots, elephants eat those in the middle of the tree, wildebeests like short grass and zebras prefer longer grasses.

Answer 37

browsers

Question 38

Temperate grassland biomes have very cold winters, hot and dry summers with sparse and uneven rainfall that produces _______ soil.

Answer 38

fertile

Question 39

The grasses above ground die and decompose every year and this creates ___________ for the soil.

Answer 39

fertilizer

Question 40

The _________ biome has adapted to withstand and regenerate itself following occasional fires.

Answer 40

chaparral

Question 41

Many plants have adapted to storing food reserves in hardy roots and sprouting ______ only after fire.

Answer 41

seeds

Question 42

The main types of forest biomes are the tropical rain forest, temperate forest and ______ forest.

Answer 42

boreal

Question 43

_______ or taiga is one of the types of forest biome and has a sub-arctic climate with a skyline dominated by coniferous evergreen trees. There are not very many species living here as it is too cold.

Answer 43

Boreal

Question 44

Even though _____________ forests only cover 2% of the Earth’s land space, it is the habitat for an estimated 50% to 80% of all land species.

Answer 44

tropical rain

Question 45

The multiple layers of specific plants and animal life that can be accommodated in a tropical rain forest are considerable and hence permit extensive ______________.

Answer 45

biodiversity

Question 46

Mountain biomes are critical ecologically because they make up 20% of the Earth’s land surface and house forests, contain specific species not found anywhere else and play an important role in the __________ cycle.

Answer 46

hydrologic

Question 47

Mountain biomes also serve as a __________ for animals from low-lying areas who have been forced to higher ground and affect sea levels via the increase or decrease in glacial ice, stored in the mountains of Antarctica.

Answer 47

sanctuary

Question 48

The biosphere and its ecosystems can be divided into the _______ and biotic components.

Answer 48

abiotic

Question 49

The abiotic components refer to the __________ aspects of the environment, like water and air. The biotic components refer to the living parts like plants and animals.

Answer 49

nonliving

Question 50

The abiotic components of an ecosystem consist of the ________ and chemical factors that affect biomes and aquatic life zones.

Answer 50

physica

Question 51

The existence, number and spread of a species in an ecosystem are determined by the _________ level of that species to one or more physical or chemical factors

Answer 51

tolerance

Question 52

Every population in an ecosystem has a level to various physical and chemical factors. For example, some plants thrive in sunlight while others like the shade. Some species have a ______ range of tolerance and others a narrower range.

Answer 52

broad

Question 53

An important ecological principle tied to the law of tolerance is the ________ factor principle.

Answer 53

limiting

Question 54

This principle states that too much or too little of a particular ________ factor may stunt or stop population growth, even if the other factors are near their optimum levels of tolerance. For example, over-watering a plant can kill it.

Answer 54

abiotic

Question 55

The living organisms in an ecosystem can be classed as producers or _________.

Answer 55

consumers

Question 56

Producers are those living organisms that create their own food from the environment’s __________. Examples of producers are green plants (land), algae (water) and phytoplankton (water).

Answer 56

compounds

Question 57

Consumers can be categorized as herbivores, omnivores, carnivores, scavengers and __________.

Answer 57

detrivores

Question 58

Detrivores are made up of _________ feeders and decomposers. The former (for example, crabs and earthworms) consume the extracted nutrients from partially rotting organic matter. The latter (for example, types of bacteria and fungi) recycle organic matter in the biosphere).

Answer 58

detritus

Question 59

Producers, also known as ___________ organisms, are those living members of the ecosystem that manufacture their own food using simple inorganic materials.

Answer 59

autotrophic

Question 60

Examples of simple __________ materials include water, carbon dioxide and salts.

Answer 60

inorganic

Question 61

Examples of ___________ organisms include trees, plants and phytoplankton (algae).

Answer 61

autotrophic

Question 62

Producers are typically ________________ plants and they vary with the type of ecosystem.

Answer 62

photosynthetic

Question 63

Heterotrophs (_________) are living organisms that ingest other organisms.

Answer 63

consumers

Question 64

The vast majority of heterotrophic organisms are ________. They feed on the tissues of producers or on that of other consumers.

Answer 64

animals.

Question 65

An ecosystem will exist and thrive through a mixture of matter recycling and one-way ______ flow.

Answer 65

energy

Question 66

The main components of an ecosystem (chemicals, energy and organisms) are connected by matter recycling, as well as the one-way ______ energy and heat flow, via organisms and then into the environment as low-quality heat.

Answer 66

solar

Question 67

The ecosystem provides us with various valuable services like natural water purification, biological control over _____ that destroy crops and the natural greenhouse effect of keeping the Earth warm enough to live on.

Answer 67

pests

Question 68

The ecosystem has natural means of managing pests. For example, ladybugs eat aphids that would otherwise destroy our crops. This is a “________” service.

Answer 68

natural

Question 69

____________ can be defined as the range of life forms and life maintaining processes that survive best in the various conditions found on Earth

Answer 69

Biodiversity

Question 70

This is the definition of biodiversity and includes genetic, species, ecological and ___________ diversity.

Answer 70

functional

Question 71

The consequences of a loss of biodiversity are the reduction of the availability of _________ services and adaptability of species and ecosystems to altering environmental conditions

Answer 71

ecosystem

Question 72

The many different species on the planet have genetic codes that have evolved over millions of years as the environmental conditions have changed. Hence, this forms part of the groundwork for adapting to future changes. Loss of biodiversity will reduce this groundwork and hence affect ______________ in the future.

Answer 72

adaptability

Question 73

It is of fundamental importance to maintain a stable level of biodiversity on the Earth because the loss of species experienced in the last century will take _________ years to replace by speciation.

Answer 73

5 million

Question 74

Developing and establishing new species takes a very long time, especially in life forms that have longer ______________ cycles, like humans.

Answer 74

reproductive

Question 75

Ecologists and conservationists argue that the Earth’s biodiversity needs to be protected because the genes, ecosystems, species and ecological processes have an instrumental and _________ value.

Answer 75

intrinsic

Question 76

Intrinsic value means simply because it exists, regardless of the value provided to humans. The instrumental value relates to the ___________ of biodiversity to humans.

Answer 76

usefulness

Question 77

The instrumental value of ____________ includes supplying food, fuel, fiber, paper and medicine or lumber.

Answer 77

biodiversity

Question 78

Humans can appreciate the recreational beauty of nature in a non-___________ way by choosing eco-tourism when going on vacations.

Answer 78

consumptive

Question 79

Ideally eco-tourism should not cause any harm to the _____________, provide an income to the indigenous population as a motivation to maintain the area’s natural ecosystem and generate funds to run conservation programs.

Answer 79

environment

Question 80

_________ is one of the most popular hobbies in America.

Answer 80

gardening

Question 81

Surveys conducted during the past several years have consistently ranked gardening among the top ____ most popular American hobbies.

Answer 81

ten

Question 82

A food chain is a sequence of _________, where each member uses the next one in line as a source of food

Answer 82

organisms

Question 83

This is the definition of a food chain and shows how energy and nutrients move from one organism to another in an __________.

Answer 83

ecosystem.

Question 84

A __________ is made up of a number of trophic levels, with the producers at the first level and consumers at the subsequent levels

Answer 84

food chain

Question 85

A trophic level is a ________ level and this determines the position of an organism in a food chain. Primary consumers occupy the second level, secondary consumers the third and tertiary consumers the fourth. There are rarely more than four trophic levels in an ecosystem.

Answer 85

feeding

Question 86

A food ___ describes a series of food chains that are interlinked as a result of organisms participating in more than one food chain.

Answer 86

web

Question 87

This is the definition of a food web and occurs regularly as most species take part in ________ food chains.

Answer 87

several

Question 88

In a food web or chain, the chemical energy stored in biomass is transferred from one organism to another and the level of energy that is transferred from one trophic level to the next is called ecological __________.

Answer 88

efficiency

Question 89

The amount of usable energy that is transferred is called ecological efficiency and is typically 10% (90% loss). Hence, the greater the number of trophic levels, the greater the loss of _______ energy.

Answer 89

usable

Question 90

The rate at which producers and plants create more plant material (biomass) via ______________ is known as the GPP.

Answer 90

photosynthesis

Question 91

This is the definition of _______________ product (GPP), which varies around the world. The areas with the highest GPP levels are shallow waters near continents and coral reefs. Those areas with the lowest GPP levels are deserts and open ocean areas.

Answer 91

gross primary

Question 92

Coral reefs are among the most _______ ecosystems on earth.

Answer 92

diverse

Question 93

Coral reefs are among Earth’s most biologically diverse ecosystems, harboring hundreds of thousands of ________ worldwide

Answer 93

species

Question 94

As producers are the ultimate source of all food in an ecosystem, the number of consumers is limited by the Earth’s ___.

Answer 94

NPP.

Question 95

The _____________ productivity (NPP)is the biomass energy left for use by consumers after the producers expend some of that energy for their own respiration.

Answer 95

net primary

Question 96

Organic material that derived from plants as a result of ______________ is called biomass.

Answer 96

photosynthesis

Question 97

Biomass is not fossilized material (oil, coal, gas, etc) but fresh material that can _____ again after being harvested.

Answer 97

grow

Question 98

Biomass energy is derived from three distinct energy sources: wood, _____ and alcohol fuels.

Answer 98

waste

Question 99

Among renewable energy sources, only _______________ power provides more energy than biomass.

Answer 99

hydroelectric

Question 100

Between 60 and 70 percent of wood energy consumption comes from _______ liquor.

Answer 100

pulping

Question 101

Wood energy accounts for nearly 80 percent of all ________ energy consumption in the US. Pulping liquor (or black liquor) is a byproduct of the pulp, paper and paperboard manufacturing process.

Answer 101

biomass

Question 102

Municipal Solid Waste (MSW) and landfill ___ are the main contributors to waste energy.

Answer 102

gas

Question 103

The second largest source of biomass energy is waste energy. Unsorted household waste, including some plastics, can be combusted as a mixed fuel in large MSW ______________.

Answer 103

incinerators.

Question 104

Biomass alcohol fuel (ethanol) is derived almost exclusively from ____.

Answer 104

corn

Question 105

Ethanol is similar to methanol and can be produced from sugar cane, grain crops, wood and agricultural waste. Natural alcohol fuels can be added to gasoline in amounts up to 10 percent without making any _______ modifications.

Answer 105

engine

Question 106

Biogeochemical cycling refers to the cycling of the necessary ________ atoms, molecules and ions from the abiotic environment to living organisms and back again.

Answer 106

nutrient

Question 107

This is the definition of biogeochemical cycling and is also known as _________ cycles.

Answer 107

nutrient

Question 108

The main processes in the water cycle are evaporation, transpiration, condensation, precipitation, infiltration, ___________ and runoff.

Answer 108

percolation

Question 109

Infiltration concerns the movement of water in the _____ and is a step in the water purification cycle

Answer 109

soil

Question 110

Photosynthesis by producers and _______ respiration by living organisms cycles carbon in the biosphere.

Answer 110

aerobic

Question 111

The oxygen rich cells in living organisms break down various organic compounds and convert it back into ________________.

Answer 111

carbon dioxide

Question 112

Fossil fuels are created over ________ of years when buried dead plant matter and bacteria are compressed between sheets of sediment.

Answer 112

millions

Question 113

This is the process for the creation of fossil fuels and the ________________ is not released into the air until the fuel is mined and burned or these deposits are naturally exposed to the air by geological processes.

Answer 113

carbon dioxide

Question 114

The ________ cycle consists of the following stages: nitrogen fixation, nitrification, assimilation, ammonification and denitrification.

Answer 114

nitrogen

Question 115

Ammonification occurs when specialized bacteria convert nitrogen-rich organic compounds, wastes and dead organisms into ammonia and water-soluble salts containing ammonia _____.

Answer 115

ions

Question 116

__________ is cycled via the water, the Earth’s crust and living organisms.

Answer 116

Phosphorus

Question 117

Phosphorus is usually found in dust particles, rock formations and ocean bottom sediments. It enters the water from runoff, for example, from fertilizer or when it has been added into an ecosystem to promote ___________ growth.

Answer 117

biological

Question 118

Sulfur dioxide reacts with certain chemicals in the atmosphere and sulfur trioxide reacts with the water droplets in the atmosphere and falls as ____ rain.

Answer 118

acid

Question 119

These are components of acid deposition and can _____ plant and water life.

Answer 119

harm

Question 120

The two fundamental principles to achieving ecosystem sustainability are the use of renewable _____ energy and the recycling of chemical nutrients necessary for sustaining the growth, development and reproduction of its organisms.

Answer 120

solar

Question 121

Solar energy is the Earth’s most critical energy source and it is constant and renewable. We should make full use of it to achieve ________________.

Answer 121

sustainability

Question 122

Scientists believe that the Earth went through a biological and ________ evolution billions of years ago that led to the development of the very diverse planet that we are today.

Answer 122

chemical

Question 123

This relates to the evolution from single-celled prokaryotic _________ to single-celled eukaryotic and then multicellular organisms.

Answer 123

bacteria

Question 124

The theory of _________ states that all species originated from earlier species.

Answer 124

evolution

Question 125

This is the theory of evolution and explains why life is so ________ today that all species originated from previous, ancestral specie

Answer 125

diverse

Question 126

According to scientific research evolution alters the genetic makeup of a __________ over time.

Answer 126

population

Question 127

The __________ changes over time to adapt to changes in the environmental conditions.

Answer 127

gene pool

Question 128

The term microevolution describes minor genetic changes in a population over time; whereas macroevolution indicates a long-term, major change where new species are formed and others are made _______.

Answer 128

extinct

Question 129

Over time, species do become extinct for various reasons, for example when they are unable to ______ to new changes in the environment.

Answer 129

adapt

Question 130

Variations in the genetic ____ are a consequence of mutations which can occur at random and are the only source of totally new genetic raw material.

Answer 130

code

Question 131

Mutations change the genetic code and result from exposure to _________, for example radioactivity, and are passed on to the next generation where those mutated cells are reproductive cells. Some are harmless and may even benefit a species but some are not.

Answer 131

mutagens

Question 132

The term natural selection means that certain members in a population possess genetic traits that _______ their odds of survival and reproducing.

Answer 132

improve

Question 133

Natural selection causes an _______ (a special gene that has more than one molecular form), that has beneficial traits to become increasingly common in future generations. This trait must be heritable and lead to differential reproduction, so that this group can be more successful at reproducing than other groups.

Answer 133

allele

Question 134

When a population of a species is faced with a change in environmental conditions it can adapt through natural _________, migrate or become extinct.

Answer 134

selection

Question 135

By migrating to a new _________ with more habitable conditions for that population, they can continue surviving.

Answer 135

location

Question 136

Artificial selection occurs where humans intervene through selective breeding to change the _______ makeup of a population of a species.

Answer 136

genetic

Question 137

This is used to create species that possess traits viewed as desirable by humans. For example, this method has been utilized to _____________ wild animals.

Answer 137

domesticate

Question 138

Interactions between species can result in a microevolution known as ___________ as alterations in the gene pool of one of the interacting populations causes the gene pool of the other population to also change.

Answer 138

coevolution

Question 139

This is the theory propounded by some biologists. It results in a kind of “arms race” between two populations consisting of adaptation after adaptation to gain the upper hand in the __________.

Answer 139

ecosystem

Question 140

An ecological _____ refers to all the factors that affect the life and reproduction of a particular species.

Answer 140

niche

Question 141

An ecological niche can include the species level of tolerance, its role in energy flow and matter recycling and its quantity and consumption of natural __________.

Answer 141

resources

Question 142

A generalist species has a broad niche in that it can live in many places, eat many different things and tolerate a wide range of environmental conditions; whereas a __________ species has a narrow niche and has to live in certain places, eat particular things and has a low tolerance to environmental conditions.

Answer 142

specialist

Question 143

Generalist species examples include cockroaches, rats and humans. Examples of ___________ species include pandas, which can only eat bamboo and tiger salamanders that can only breed in fishless ponds.

Answer 143

specialist

Question 144

Adaptations have evolutionary limitations as it can only occur in genes already present in the species makeup and is restricted by the ____________ capacity of that species.

Answer 144

reproductive

Question 145

Animals that reproduce speedily can speedily adapt to a change in environmental conditions whereas a slower reproducing species such as elephants or humans cannot adapt so quickly and so the process takes a long time, usually _________ of years.

Answer 145

millions

Question 146

The process of __________ leads to the development of a new species by natural selection.

Answer 146

speciation

Question 147

This is the definition of speciation; where two species come from one. The two steps for speciation are ___________ isolation and reproductive isolation.

Answer 147

geographic

Question 148

Speciation and extinction have been affected by the major movement of the continents, gradual climate change and alterations in the Earth’s orbit around the sun and rapid climate change resulting from ____________ events.

Answer 148

catastrophic

Question 149

These events, like major volcano eruptions or meteorite crashes, seriously affect the energy flow and _______ and nutrient cycles. Hence, it has a serious impact on speciation and extinction.

Answer 149

matter

Question 150

Background extinction differs from mass extinction in that the former describes the _______ disappearance of species whereas the latter refers to a widespread elimination of many species.

Answer 150

gradual

Question 151

Biodiversity increases with speciation and decreases with __________.

Answer 151

extinction

Question 152

___________ creates new species and hence increases biodiversity whereas extinction reduces the number of species and results in a loss of biodiversity.

Answer 152

Speciation

Question 153

Ecologists explain the community structure of an ecosystem by its physical appearance, _____ structure, species diversity and quantity.

Answer 153

niche

Question 154

This is one of the key descriptive factors of an __________ and assists ecologists from differentiating one ecosystem from another.

Answer 154

ecosystem

Question 155

The factors that determine species diversity are latitude in ___________ communities and depth and pollution in aquatic communities.

Answer 155

terrestrial

Question 156

The latitudinal species _________ shows that species diversity is greatest in the tropical rain forests and lowest in the polar regions like the arctic tundra.

Answer 156

gradient

Question 157

Native species refers to those species that normally reside and thrive in a particular _________.

Answer 157

ecosystem

Question 158

Exotic species describes species that were ____________ or deliberately introduced by humans into an ecosystem or those that had migrated there.

Answer 158

accidentally

Question 159

For example, where a few specimens of plant material attach itself to a vehicle and is released into another ecosystem. With widespread air travel, the ___________ introduction of new species into new ecosystems will become more prevalent.

Answer 159

accidental

Question 160

An _________ species describes a species that reacts to changes in the ecosystem speedily and hence acts as an early warning signal for potential damage.

Answer 160

indicator

Question 161

_____ are a good indicator species because they are abundant, found virtually everywhere and react quickly to environmental changes.

Answer 161

Birds

Question 162

Some ecologists believe that ________ species play a pivotal role in ecosystems, proportionally greater than other species.

Answer 162

keystone

Question 163

The keystone species have a greater _____________ with other species and can affect their health and survival. They may also process proportionally more matter than other species relative to their size.

Answer 163

interaction

Question 164

Pollination, cycling of animal waste, dispersing undigested seeds scattered by certain animals and _________ to keep the numbers of certain species in check are some of the key functions performed by keystone species.

Answer 164

predation

Question 165

Carnivores eat other animals and this helps to keep their population under control. Top predator keystone species such as the shark, wolf and alligator stabilize ecosystems by ___________ the populations of certain species.

Answer 165

regulating

Question 166

The great white shark is an example of an ____ predator.

Answer 166

apex

Question 167

Apex predators are animals which have no ________ predators in their ecosystem.

Answer 167

natural

Question 168

Loss of keystone species can start a ______ effect on an ecosystem, which could lead to species extinction and population crashes.

Answer 168

ripple

Question 169

The ripple effect, is also known as cascade or _______ effect. The consequences are not limited as loss of keystone species has a disproportionately negative impact on an ecosystem.

Answer 169

domino

Question 170

Species within an ecosystem may have to interact with each other and these interactions can be classified as _____________ competition, predation, parasitism, mutualism and commensalism.

Answer 170

intraspecific

Question 171

Mutualism occurs when two species interact to mutually ________ each other. Examples include pollination, receiving food and protection.

Answer 171

benefit

Question 172

When members of the ____ species compete for the same resources, intraspecific competition exists.

Answer 172

same

Question 173

Intraspecific competition can be very fierce. Examples include plants secreting chemicals to restrict the growth of new plants around it and ________________ where some organisms, like lions mark their territory and protect it against other lions and other animals.

Answer 173

territoriality

Question 174

There two types of competition for resources by species are interference competition, where a species limits the resources that can be accessed by another species and ____________ competition, where the various species have about the same access to the resource but differ in the speed and efficiency in which they can obtain it.

Answer 174

exploitation

Question 175

An example of exploitation competition occurs when Humans’ use of land and resources outstrips that available for other species and hence _________ these species of the right to life.

Answer 175

deprives