3.6 HUMAN IMPACT

Endangered species

Species population size fallen to critical level at risk of extinction

Endangered species

Permanent loss of a species when no individuals remain

Selection pressure

Factor affects which organisms survive and reproduce

Causes of endargerment

Natural selection

Habitat destruction

Pollution

Hunting and collecting

Competition from Domestic animals

Natural selection and endargement

Environment changes → new selection pressure

Individuals without favourable alleles die

Population size decrease

• Small population → reduced genetic diversity → less able to adapt → extinct

Habitat destruction and enddargement

Destruction of habitat by human activity

• Deforestation

• Removal of hedgerows

• Urbanisation

Effects

• Loss of food sources

• Loss shelter and breeding sites

• Population fragmentation

Smaller isolated populations → interbreeding → reduced genetic variation

Pollution and endangerment

Release harmful substances into environment

• PCBs

• Oil spills

• Fertilisers

Effects

• Toxicity → death

• Bioaccumulation → toxins build up in organism

• Biomagnification → concentration increase up food chain

Hunting and collecting

Removal of organisms by humans

• Poaching

• Overfishing

• Collecting rare plants

Effects

• Reduce population size

• Remove breeding individuals

Competition from domestic animals - endargement

Livestock compete with wild species

• Food

• water

• Space

Wild species outcompeted → population decline

Conservation definition

Sensible management of biosphere to maintain and enhance biodiversity

Why is conservation important

Ethical

• All species have intrinsic value

• Humans have moral responsibility to prevent extinction

Genetic

• Species contain unique alleles

• Potential medicine use

• Agriculture use

• Future adaption

Loss of species → irreversible loss of genetic information

Ecosystem stability

High biodiversity → Stable ecosystems

• More species → more complex food webs

• Less risk of ecosystem collapse

SITU conservation

Conservation of species in their natural habitat

Methods of conservation SITU

Nature reserves

• Protected areas

• Limit human activity

SSSI (Sites of special scientific interest)

• Areas protected to ecological importance

Habitat protection

• Prevent habitat destruction

• Restore damaged ecosystems

International cooperation

• Counties restrict trade in endangered species

EX SITU Conservation ( in captivity)

Conservation of species outside their natural habitat

Methods of EX SITU conservation

Zoos

• Protect endangered control breeding

Botanic gardens

• Protect rare plant species

Breeding programmes

• Maintain genetic diversity

• Increase population size

Gene Sperm and Seed banks

Reintroduction programme

• Release species back into wild

Conditions needed for reintroduction programme

Suitable habitat

Threats removed

Gene banks

Preserve alleles and genetic diversity

Storage of genetic material for future

• Sperm and seed

Gene pool definition

Total number of alleles in a population

Why must gene pools be conserved

Maintain genetic diversity

More alleles → more variation

Why prevent interbreeding?

Small populations → increased breeding

• Increased expression of harmful alleles

• Reduced fitness

Why is allowing adaption beneficial?

Greater variation → Higher chance of survival under environmental change

Gene pools in the wild

Large populations

Natural selection maintains variation

Gene pools in captivity

Smaller populations

Must be managed carefully

Agricultural exploitation

The use of land and natural resources to produce food and materials for human use

Conflict production vs conservation

Production

• Increasing food, resources to meet human demand

• Damage ecosystem

Conservation

• Protecting human ecosystems and biodiversity

• Limits production

Deforestation definition and reasoning

Large scale removal of trees

• Agriculture (farming and gazing)

• Timber production

• Urbanisation

• Biofuel

Consequences of deforestation

Loss of biodiversity

• Habitats destroyed

• Species become endangered → extinct

Increased CO₂ → global warming

• Less photosynthesis absorb

• Burning release

Soil erosion

• No roots to hold soil

• Nutrients lost → less fertile land

Disrupted water cycle

• Less transpiration

• Reduced rainfall

Sustainable forest management

Replanting - after cut

Regeneration - allow natural recovery

Protected areas - forest area no cutting

Preserving natural woodland - maintain biodiversity and gene pool

Overfishing definition and consequences

Removal of fish at a faster rate than they can reproduce

Decline in fish stock

• Rapid population decrease

Reduced gene pool

• Fewer individuals → less genetic diversity

Ecosystem imbalance

• Food chain disrupted

Population collapse - may not recover

Methods to regulate fishing

Catch quotas - limit number caught

Net mesh size - allow young juvenile escape

Closed seasons- fishing banned during breeding periods

Exclusion zones - allow fish reproduce

Landing size regulations - allow fish of a certain size to be caught

Fish farming definition and advantages

Breeding and raising fish in controlled environments

• Increased fish population

• Reduces pressure on wild fish stocks

Problems with fish farming

Disease spread

• high density -. infections spread easily

Waste pollution

• Accumulates → water pollution

Reduced genetic diversity

• Inbreeding in farmed fish

Escape of farmed

• Interbreed → weaken gene pool

Why are fish escaping fish farms bad

• Foreign species into → new space decrease biodiversity reduce wild fish numbers

• Compete for food, mates, habitat disrupt food chains

• Breed with wild fish reduce genetic diversity dilute gene pool (wild→ extinct)

Fish farms and parasites

Closely packed parasites spread easily fish to fish

Cannot be easily killed as resistant to pesticides

Concerns about illegal unregulated introduction

Diseases introduction (TB)

Destruction of habitat

Wrong species not so well adapted introduced

Factors to be considered when introducing species

Research: Resources and expertise on protection

Consultation: Neighbouring land owners

Correct species: Suitable disease free donor population

Human pressures on the environment definition

The impact of human activities on ecosystems and the environment

Examples of human pressures on environment

Population growth

Increased food demand

industrialisation

Pollution

Deforestation

Overfishing

All increase resource use → reduce biodiversity

Sustainability definition

Meeting present needs without compromising ability of future generations to meet their own needs

Why is sustainability needed

Natural resources are finite

Ecosystems can be damaged permanently

Biodiversity loss irreversible

How is sustainability achieved

1. Change human attitude

Awareness issue valuing conservation (reduce waste, sustainable products)

2. Informed choices

Decisions based on environmental impact

(Buying sustainably sourced products, reduce meat consumption, renewable energy)

Consumers influence environmental → informed decision-making

Environmental monitoring

The systematic measures and recording of environmental conditions over time

Purpose of environmental monitoring

Detect changes in ecosystem

Identify pollution levels

Track biodiversity

Why is environmental monitoring needed

Provide data to

• Asses human impact

• Inform conservation strategies

• Guide decision-making

Role of science and tech

Allow to predict and manage environmental impact

Uses of science and tech

Prediction

• Climate change

• Species decline

• Pollution effects

Data

Satellites → deforestation monitoring

Sensors → pollution levels

Planning

• Policies

• Manage resources

• Reduce environmental damage

Countermeasures definition

Action taken to reduce or prevent environmental damage

Types of countermeasures

1. Preventative measures - stop damage before

Limiting deforestation, Fishing quotas, Pollution controls

2. Replacement of Activities - Replace activities with less damaging alternatives

Renewable energy (not fossil fuels) Sustainable farming (not intensive) Fish farming

Multidimensional thinking definition and factors to consider

Considering multiple factors when making decisions

• Environmental impact

• Economic cost

• Social impact

Interdisciplinary collaboration definition

Different fields working together to solve problems

• Scientists

• Governments

• Economists

• Environmentalists

Political decision making

Government decide environmental management

Based on sound scientific evidence

Why is political decision making important

Accurate predictions → Climate change, species decline, pollution effects

Informed policies → Set regulations, protect ecosystems, manage resources

Decisions without science

Be inaccurate

Cause further environmental damage

Planetary boundaries

Define safe operating space for humanity based on earth system limits

• Within boundaries → Stable

• Crossed → irreversible environmental change

Tipping point definition

Critical threshold beyond which environmental change become rapid and irreversible

Main driver of previous environmental change

Industrial revolution main driver environmental change

Many boundaries already or close to being crossed

Biodiversity boundary (CROSSED)

Rate of extinction too high

Causes

• Habitat destruction (Marine, coral reef)

• Climate change

• Pollution

Effects

• Species extinction

• Loss of gene pools -. reduced genetic diversity

Management of biodiversity

Biodiversity monitoring

Gene banks

Public awareness

Climate change boundary (Crossed)

Increase in greenhouse gas

Source

• Fossil fuels

• Deforestation, agriculture

Effects

• Rising sea Extreme weather, food shortage

• Habitat shift, extinction

Biofuel alternative energy source

• Compete with food production

• Cause deforestation

Nitrogen cycle

Nitrogen fertilisers → excess in water

Eutrophication → excess algal bloom

Eutrophication

Nitrogen and phosphorus in water

Algal bloom on water surface block sunlight

Plants at bottom die no photosynthesis

Decomposers (bacteria and fungi) decompose dead organic matter

Aerobic respiration use up oxygen in water

Water becomes deoxygenated - oxygen requiring species die

Denitrification anaerobic bacteria reduce nitrates

Land use boundary (Crossed)

Land for agriculture

Food production vs conservation

• Intensive farming

• Deforestation

Political - food demand and economic pressure

Fresh water boundary (Avoidable) importance and solution

Importance

• Drinking

• Agriculture

• Industry

Sources → Rivers, lake, ground water

Solution- Desalination remove salt from seawater

• Expensive and energy- intensive

Chemical pollution (Unquantified) effects

SO₂ and Nitrogen oxides

• Air pollution

• Acid rain

Aerosols (Unquantified) effects

Tiny particles in the air

• Respiratory problems

• Climate change effects

Ocean acidification (avoidable) effects

CO₂ dissolved → Carbonic acid

• Damage shells (calcium carbonate)

• Harms marine life worsen local water conditions (fish farming)

Ozone layer (avoided) process and solution

CFCs

Release chlorine → destroy ozone

Montreal protocol ozone depletion reduced → boundary avoided

Natural selection and extinction

Changing environment some species unsuitable and not adapted

Cannot evolve in short period of time

Slow mutation rates

Increased human population causing environmental change