CIE AS/A Level Biology -18.3 Conservation- Study Notes- New Syllabus

CIE AS/A Level Biology -Conservation- Study Notes- New Syllabus

Ace A level Biology Exam with CIE AS/A Level Biology -Conservation- Study Notes- New Syllabus

Key Concepts:

explain why populations and species can become extinct as a result of:
- climate change
- competition
- hunting by humans
degradation and loss of habitats
outline reasons for the need to maintain biodiversity
outline the roles of zoos, botanic gardens, conserved areas (including national parks and marine parks), ‘frozen zoos’ and seed banks, in the conservation of endangered species
describe methods of assisted reproduction used in the conservation of endangered mammals, limited to IVF, embryo transfer and surrogacy
explain reasons for controlling invasive alien species
outline the role in conservation of the International Union for Conservation of Nature (IUCN) and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)

CIE AS/A Level Biology 9700-Study Notes- All Topics

Causes of Extinction in Populations and Species

❄️ 1. Climate Change

Definition: Long-term changes in temperature, rainfall, or seasonal patterns.
Impact on species:
- Alters habitats and availability of food and water.
- Species unable to adapt quickly or migrate may die out.
Example: Polar bears are at risk due to melting Arctic ice reducing hunting grounds.

⚔️ 2. Competition

Definition: Struggle between organisms for limited resources such as food, water, or territory.
Impact on species:
- Stronger or better-adapted species may outcompete weaker ones, leading to local or total extinction.
Example: Native species in New Zealand declining due to introduced mammals like rats and stoats.

🔫 3. Hunting by Humans

Definition: Direct removal of species by humans for food, sport, or trade.
Impact on species:
- Populations decline faster than their reproductive rate, leading to extinction.
Example: Passenger pigeons went extinct due to excessive hunting in the 19th century.

🏞️ 4. Degradation and Loss of Habitats

Definition: Destruction or alteration of natural habitats through human activity (deforestation, urbanization, pollution).
Impact on species:
- Loss of shelter, breeding sites, and food sources.
- Species unable to relocate or adapt may die out.
Example: Orangutans are critically endangered due to rainforest destruction in Borneo and Sumatra.

📊 Summary Table: Causes of Extinction

Cause	Mechanism	Example
Climate change	Alters habitats; species fail to adapt	Polar bears
Competition	Outcompeted by other species	Native birds vs. invasive rats
Hunting by humans	Population reduced faster than reproduction	Passenger pigeons
Habitat degradation/loss	Loss of shelter, food, breeding sites	Orangutans in rainforests

🧠 Key Takeaways:
Extinction often results from a combination of factors rather than a single cause.
Human activities greatly accelerate natural extinction rates.
Conservation efforts (protected areas, anti-poaching laws, habitat restoration) are essential to prevent further loss of species.

Reasons for the Need to Maintain Biodiversity

🌎 1. Ecological Stability

Biodiversity ensures healthy ecosystems.
Different species interact to recycle nutrients, pollinate plants, control pests, and maintain balance.
Loss of species can disrupt food chains and ecosystem functioning.

💰 2. Economic Benefits

Many species provide resources for humans:
- Food (crops, fish, livestock)
- Medicines (plants, fungi, microorganisms)
- Raw materials (timber, fibers)
Reduced biodiversity can lead to loss of these resources.

🌱 3. Cultural and Aesthetic Value

Biodiversity contributes to recreational, spiritual, and cultural experiences.
Nature inspires art, tourism, and well-being.

🔬 4. Scientific and Medical Research

Diverse species are used in research and biotechnology.
Genetic diversity helps in developing new medicines, crops, and treatments.

☀️ 5. Climate Regulation and Environmental Services

Forests, wetlands, and oceans regulate climate and store carbon.
Biodiversity supports soil fertility, water purification, and flood control.

📊 Summary Table: Importance of Biodiversity

Reason	Benefit to Humans and Ecosystem
Ecological stability	Maintains balanced ecosystems, nutrient cycling
Economic benefits	Food, medicine, raw materials
Cultural & aesthetic value	Recreation, tourism, inspiration
Scientific & medical research	Development of drugs, crop improvement
Climate & environmental services	Carbon storage, soil fertility, water purification

🧠 Key Takeaways:
Biodiversity is essential for life on Earth.
Loss of biodiversity can lead to ecosystem collapse, economic loss, and reduced quality of life.
Conservation efforts like protected areas, sustainable use, and habitat restoration are critical.

Roles of Conservation Facilities and Strategies in Protecting Endangered Species

🐅 1. Zoos

Maintain captive populations of endangered species.
Enable breeding programs to increase population numbers.
Educate the public about wildlife conservation.
Example: Breeding of the black-footed ferret in North American zoos.

🌺 2. Botanic Gardens

Preserve rare and endangered plant species.
Provide material for research, education, and reintroduction into the wild.
Example: Royal Botanic Gardens, Kew, maintains a collection of threatened plant species.

🏞️ 3. Conserved Areas (National Parks & Marine Parks)

Protect natural habitats and biodiversity in situ.
Allow species to live in their natural environment with minimal human interference.
Example: Yellowstone National Park (USA) protects wildlife like wolves and bison.
Marine parks: Protect marine biodiversity, e.g., Great Barrier Reef Marine Park.

❄️ 4. Frozen Zoos

Preserve genetic material (sperm, eggs, embryos, DNA) of endangered animals.
Provide material for future breeding programs or cloning.
Example: Frozen zoo at the San Diego Zoo maintains genetic samples of rare species.

🌱 5. Seed Banks

Store seeds of endangered or economically important plants at low temperatures.
Ensure future availability for reintroduction or agriculture.
Example: Svalbard Global Seed Vault in Norway.

📊 Summary Table: Conservation Strategies

Facility / Strategy	Main Role	Example
Zoos	Captive breeding, education	Black-footed ferret breeding programs
Botanic gardens	Plant conservation, research, reintroduction	Kew Gardens threatened plant collection
National / Marine Parks	Habitat protection, in situ conservation	Yellowstone NP, Great Barrier Reef MP
Frozen zoos	Genetic preservation for future breeding/cloning	San Diego Zoo Frozen Zoo
Seed banks	Long-term storage of plant genetic material	Svalbard Global Seed Vault

🧠 Key Takeaways:
Conservation of endangered species requires both in situ and ex situ strategies.
Zoos, botanic gardens, and parks protect species directly in their habitats or in captivity.
Frozen zoos and seed banks preserve genetic diversity for future restoration efforts.
Combining these approaches increases chances of survival for threatened species.

Assisted Reproduction in the Conservation of Endangered Mammals

🌱 Purpose

To increase population numbers of endangered mammals.
Helps overcome breeding difficulties in captivity.
Maintains genetic diversity.

🔬 1. In Vitro Fertilization (IVF)

Eggs (ova) are collected from a female.
Fertilized with sperm outside the body in a laboratory.
Resulting embryos are grown for a short period before transfer.
Use in conservation: Produces offspring when natural mating is difficult.
Example: IVF has been used for the giant panda.

🐄 2. Embryo Transfer (ET)

Embryos are created via natural mating or IVF.
Embryos are transferred into the uterus of a healthy surrogate female.
Allows a female to produce more offspring than she could naturally.
Use in conservation: Increases reproductive output of endangered females.
Example: African wildcat embryos transferred into domestic cats.

🤰 3. Surrogacy

An embryo from one female (genetic mother) is implanted into another female (surrogate).
The surrogate carries the pregnancy to term.
Use in conservation: Helps species with low reproductive rates or when females cannot carry pregnancies.
Example: Northern white rhino embryos implanted into southern white rhino surrogates.

📊 Comparison Table: Assisted Reproduction Methods

Method	Process Summary	Conservation Use	Example
IVF	Egg + sperm fertilized in lab	Produces offspring when mating is difficult	Giant panda
Embryo Transfer (ET)	Embryos implanted into surrogate females	Increases reproductive output	African wildcat
Surrogacy	Embryo carried by a different female	Overcomes pregnancy issues in endangered species	Northern white rhino

🧠 Key Takeaways:
Assisted reproduction enhances breeding success of endangered mammals.
IVF, embryo transfer, and surrogacy help maintain genetic diversity and boost population numbers.
These methods are complementary to in situ and ex situ conservation efforts.

Reasons for Controlling Invasive Alien Species (IAS)

🌱 1. Protect Native Biodiversity

Invasive species compete with native species for food, space, and resources.
Can outcompete or prey on native species, leading to population decline or extinction.
Example: The cane toad in Australia reduces populations of native frogs and small reptiles.

⚖️ 2. Prevent Ecological Imbalance

IAS can alter habitats and disrupt natural ecological processes.
May change nutrient cycling, water availability, or fire regimes.
Example: Water hyacinth blocks sunlight in rivers, affecting oxygen levels and aquatic life.

💰 3. Protect Agriculture and Economy

Some invasive species damage crops, livestock, or fisheries.
Control is necessary to reduce economic losses in agriculture and fisheries.
Example: Fall armyworm attacks maize crops, reducing yields.

🩺 4. Protect Human Health

Some invasive species carry diseases or are toxic to humans.
Example: Mosquito species like Aedes aegypti spread dengue and Zika viruses.

📊 Summary Table: Reasons for Controlling IAS

Reason	Impact of Invasive Species	Example
Protect native biodiversity	Outcompete or prey on native species	Cane toad in Australia
Prevent ecological imbalance	Alter habitats and natural processes	Water hyacinth in rivers
Protect agriculture & economy	Damage crops, livestock, fisheries	Fall armyworm on maize
Protect human health	Spread diseases or toxic effects	Aedes aegypti mosquitoes

🧠 Key Takeaways:
Invasive alien species threaten native species, ecosystems, economy, and human health.
Effective control (mechanical removal, chemical treatment, biological control) is essential to maintain ecological balance and protect resources.

Role of International Organisations in Species Conservation

🐾 1. International Union for Conservation of Nature (IUCN)

Purpose: Global authority on the status of the natural world and species conservation.
Roles in Conservation:
- Assess species’ risk of extinction and maintain the IUCN Red List (Least Concern, Vulnerable, Endangered, Critically Endangered, etc.).
- Advise governments and organisations on conservation policies and strategies.
- Promote habitat protection, biodiversity research, and sustainable use of resources.
Example: Conservation strategies for the Amur leopard listed as Critically Endangered on the Red List.

🌱 2. Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)

Purpose: International agreement to regulate trade in wild plants and animals to prevent species extinction.
Roles in Conservation:
- Control and monitor international trade of endangered species through a system of permits.
- Protect species from over-exploitation due to commercial demand.
- Classify species into Appendices I, II, and III based on the level of protection required.
Example: Trade in ivory from elephants is heavily restricted under CITES regulations.

📊 Summary Table: IUCN vs CITES

Organisation	Main Role	Mechanism	Example
IUCN	Assess extinction risk, guide conservation	Red List, policy advice, research support	Amur leopard – Critically Endangered
CITES	Regulate international trade of species	Permit system, trade monitoring, Appendices	Elephant ivory trade restrictions

🧠 Key Takeaways:
IUCN focuses on assessing species’ conservation status and advising on strategies.
CITES ensures sustainable trade to prevent exploitation of endangered species.
Both organisations work internationally to protect biodiversity and prevent extinction.

CIE AS/A Level Biology -18.3 Conservation- Study Notes