Understanding Biodiversity

Biodiversity

• Variety of life in a specific area is biodiversity
• Resilient ecosystems depend on biodiversity as more biodiverse ecosystems are more stable and resistant to change

Ecosystem Biodiversity

• High biodiversity is associated with many different habitats
• Low biodiversity is associated with one or two different habitats

Species Biodiversity

• Species richness refers to the number of species within an ecosystem
• Species evenness refers to the number of individuals of each species within an ecosystem
• High species diversity leads to both high species richness and evenness
• Ecosystems are more stable and resilient to environmental changes if they have high species diversity

Genetic Biodiversity

• Genetic biodiversity refers to the number of different alleles of genes that are present
• Genetic diversity is affected by the proportion of genes with more than one allele and the number of different alleles that each gene has
• Genetic differences or diversity can exist between populations due to factors, such as differing selection pressures in different areas that affect allele frequencies
• Genetic diversity helps populations adapt and survive environmental changes

Estimating Species Numbers

• Around 8.7 million species are estimated to exist on Earth

Mass Extinction

• The number of species on Earth has varied over time
• Extinction is the disappearance of species that once existed
• Earth have experienced at least 5 mass extinction events
• There are more species alive today than in the past
• Speciation increases the number of species, and occurs at a higher rate than extinction, thus increasing global biodiversity
• Global diversity levels are higher than ever due to periods of speciation in the past

Anthropogenic Extinction

• Extinction caused by human actions is anthropogenic extinction
• Human activities play a significant role in the current mass extinction event

Case Study: North Island Giant Moa

• The North Island giant moa (Dinornis novaezealandiae) was a large, flightless, herbivorous bird in New Zealand which was extinct by the year 1300
• The moas in New Zealand were likely hunted to extinction by humans by 1300, after human arrival between 1200-1300

Case Study: Caribbean Monk Seals

• Caribbean monk seals (Neomonachus tropicalis) lived in the oceans around the Gulf of Mexico and the Caribbean, and were declared extinct in 2008
• The Caribbean monk seals may have gone extinct prior to 2008
• European colonists easily hunted these seals for their oil and meat due to their docile nature and habit of lying on rocks

Case Study: Passenger Pigeon

• The Passenger pigeon (Ectopistes Migratorius) was a migratory bird that was hunted to extinction by humans
• Billions of passenger pigeons once inhabited eastern North America in the early 1800s
• As settlers moved westward, passenger pigeons were slaughtered by the millions yearly and shipped for sale in city markets
• The passenger pigeon’s decline was officially classified as extinct from 1870, when the last known representative died on September 1, 1914

Case Study: Mixed Dipterocarp Forest

• Dipterocarps are a family of trees in the tropics
• More than 50% of southeast asia's rainforests have been gradually lost
• Forest loss in southeast asia is often caused by clear cutting, excavation for mining, and deforestation for valuable hardwood timbers
• Human-caused climate change impacts rainfall patterns as a factor contributing to forest loss
• Agriculture, specifically the development of palm oil plantations, contributes to the loss of these forests as palm oil plantations do not support biodiversity
• Overhunting, driven by meat, skin, trophies and medical practices leads to overhunting, disrupting the ecological balance

Case Study: Great Barrier Reef

• The Great Barrier Reef is the world's largest and most diverse reef ecosystem
• One of the seven natural wonders of the world and visible from space
• It is 2,300 kilometers long and covers an area larger than New Zealand
• Habitats from wetlands and rivers to beaches and coral reefs house various species
• The reef is threatened by human activities and natural events
• Climate change is the biggest threat, with other challenges including poor water quality from land-based pollution, pests, and coastal development

Evidence for the Biodiversity Crisis

• Reliable biodiversity surveys are needed across habitats, including repeat surveys
• Data analysis require assessment of species richness and evenness
• Organizations like IPBES and IUCN compile evidence for the biodiversity crisis
• IPBES is the Intergovernmental Science Policy Platform on Biodiversity and Ecosystem Services
• IUCN is the International Union for the Conservation of Nature, which publishes a list of the world's most threatened species

Reasons for Biodiversity Crisis Due to Human Population Growth

• The overexploitation of resources is caused by overfishing leading to a decline in fish population and by hunting animals for resources
• Loss of habitat for buildings caused by urbanisation
• Habitat fragmentation and less land available for agriculture result from urbanisation
• Deforestation and habitat loss is caused by clearing land for human activities
• Microplastics found in remote environments represent a form of pollution
• Increase in pest species is associated with biodiversity loss where higher biodiversity increases the number of pests predators
• Pests will gather in larger numbers in areas of monoculture as a consequence of biodiversity loss
• Alien species introduced by humans causes damage to habitats and is termed invasive species
• Diseases wipe out large numbers of species, as human-caused climate change increases the range of some diseases

In-Situ Conservation

• In-situ conservation is protecting species within their natural habitats, e.g. government-controlled national parks

Protected Areas

• National parks are government controlled areas where wildlife and the environment are protected
• Geographical space managed and protected, with strictly controlled human access
• Industrial activities like agriculture and building are tightly regulated and hunting is limited or prohibited

Rewilding

• Rewilding allows for restoration of ecosystems to a point where they can sustain themselves
• Active rewilding involves human interactions
• Passive rewilding means leaving an area alone to allow ecological processes to occur

Ex-Situ Conservation

• Ex-situ conservation is protecting species outside their natural habitats, such as in zoos and botanic gardens

Zoos

• Zoos increase the number of individuals of a species through captive breeding programs
• Artificial insemination to allow flow of genes
• Releasing individuals back into the wild is enabled by captive breeding
• Scientific research greatly benefited by in-situ conservation in zoos

Botanic Gardens

• Cuttings and seeds collected to establish species
• Captive populations of endangered species can be used in the future for reintroduction into habitats
• Major role of a Botanic garden is research

Reclamation

• Reclaiming and restoration of areas damaged by human activities

Seed Banks

• Seed banks are the process of drying and storing seeds in a temperature-controlled environment
• Seeds of the same species seed banks are collected from different sites to maintain genetic diversity
• Cool and dry conditions increase how long seeds stay viable

Tissue Banks

• Storing genetic materials from animals at very low temperatures
• Samples are collected from different individuals of the same species to maintain genetic diversity
• Germplasm in tissue banks: reproductive and somatic tissues
• Reproductive tissues can be used by a zoo in captive breeding programmes
• Somatic tissue contains the cell type contains full genome of the species and can be used for research

Advantages of Ex-Situ Conservation

• Protection from predators
• Greater control of conditions is required for breeding can ensure that the offspring survive after birth
• Technologies can increase the numbers of offspring produced

Disadvantages of Ex-Situ Conservation

• Captive populations have limited genetic diversity
• Organisms live outside of their natural habitats and lack required survival strategies
• Does not prevent destruction of the natural habitat

Advantages of In-Situ Conservation

• Organisms are not held in captivity, allowing them to develop survival strategies
• Other species are also protected in the protected habitat
• Preserve biodiversity of the ecosystem

Disadvantages of In-Situ Conservation

• Many endangered species need large areas for population survival
• Difficult to prevent poaching of endangered animals
• Genetic variety is damaged

Prioritising Species for Conservation

• Evolutionarily distinct species : those with few close relatives, unusual appearance, and those that represent a unique part of Earth's evolutionary tree
• Globally endangered species are the IUCN red list species at threat and at risk
• The EDGE Programme's focus involves protecting unique species which is Evolutionarily Distinct and Globally Endangered
• Conservation efforts for EDGE species need local, environmental, and international support

Ecological Niches

• The place where a species lives is its habitat
• A species occupies a specific niche within a habitat
• A niche is the role of a species within its habitat
• No two species can occupy the same niche within a habitat
• There will be direct competition where 2 species compete causing one to die out

Adaptations to Ecological Niches

• Species can only survive in habitats to which they are well adapted
• Abiotic factors are non-living factors of a habitat
• Biotic factors refer the living factors of a habitat

Oxygen Needs

• Obligate aerobes require continuous oxygen supply and live in oxic environments in order to metabolise substances and produce ATP through aerobic cellular respiration; oxygen serves as the final electron acceptor
• Obligate anaerobes are inhibited or killed by oxygen, live in anoxic environments, and produce ATP via anaerobic cellular respiration or fermentation and die in the presence of O2 because they lack the enzymes needed to break down toxic forms of oxygen
• Facultative anaerobes can live in either oxic or anoxic environments and produce ATP via either aerobic cellular respiration, anaerobic respiration, or fermentation

Methods of Nutrition

• Organisms need energy in the form of ATP to survive and ATP is transferred during cellular respiration
• Autotroph organisms can synthesis organic molecules from inorganic
• Heterotroph organisms gain organic molecules from the tissues of other organisms to capture chemical energy obtained from the breakdown of food molecules

Photosynthesis

• Use light energy to convert carbon dioxide
• Pigments such as chlorophyll absorb light energy to make their own organic molecules
• Transfers light energy into a chemical form that can be used by living organisms
• Release of oxygen into the atmosphere enables aerobic respiration

Holozoic Nutrition

• Heterotrophs use holozoic nutrition to gain their organic molecules from the tissues of other organisms by ingesting, digesting, absorbing and assimilating molecules
• Holozoic nutrition involves internal digestion

Mixotrophs

• Some organisms can use more than one method of nutrition
• Obligate mixotrophs must constantly have access to both methods of nutrition
• Facultative mixotrophs can survive using one method of nutrition supplemented by the other

Saprotrophs

• Heterotrophs ingest tissues of dead organisms by secreting enzymes and digesting the enzymes externally
• Saprotrophs secrete digestive enzymes to hydrolyse a large variety of biological molecules
• Decomposers leaves minerals in the surrounding soil
• The nutrients locked up in dead and waste matter would never be released without saprotrophs

Nutrition In Archaea

• Single-celled organisms comprising one of the three domains
• Phototrophic archaea use energy from light is used to generate ATP
• Halobacterium uses a pigment to absorb light energy and to pump H ions across a membrane and produces ATP by the enzyme ATP synthase in a similar way to oxidative phosphorylation and photophosphorylation
• Chemotrophic archaea produces their own carbon compounds using energy released from chemicals, which is then transferred to carbon compounds, and used for ATP production
• Some chemotrophic archaea uses energy from chemicals to directly drive ATP production
• Chemoheterotrophs: use energy released from chemicals but gain carbon compounds from other organisms
• Heterotrophic archaea: gains carbon compounds from other organisms and then use it for ATP generation

Nutrition in Hominidae

• The most existing hominids are omnivores
• Chimps are mainly frugivores
• Gorillas are mainly herbivores

Herbivory Adaptations

• Herbivores are heterotrophs that feed on plants
• Different adaptation allow organisms to survive on plant tissues
• Organism’s characteristics aids survival in its environment

Herbivory In Insects

• Aphids have specialised mouths (stylets) to pierce plant tissues and reach into the sap
• Caterpillars, grasshoppers and beetles have mouth parts (mandibles) allowing them to cut through leaves

Herbivory in Mammals

• They use flat teeth to grind plant matter
• Ruminant mammals have digestive system like a stomach with several compartments and bacteria communities to regurgitate food
• Herbivores neutralise toxins produced by plants
• Mammals use cautious sampling when they encounter a new plant

Plant Adaptations Against Herbivory

• Mechanical deterrents like cacti sharp spines and nettles toxins, and thick bark
• Toxic secondary compounds like heartbeat causing atropine and digitalis is a result of nerve inhibitors

Predator And Prey

• Predator hunts and eats animal
• Prey are animals that are hunted and consumed by predators
• Their adaptation help

Predator Adaptation

• Predator can use chemical mimicry to attack prey
• Chemicals which can subdue and capture prey
• Keen sensory organs help to search for prey
• Special body structure to kill prey

Prey Adaptation

• Their sense allows them to feel when being attacked
• Body parts help to deter and avoid
• Prey animals can mimic to either camouflage, imitate poisonous animal, or scare predators

Plant light Adaptation

• Leave adopt to carry out photosynthesis
• The plant maximize the ability absorb light energy
• Tree use uppermost layer
• The Strategy of maximizing height helps gaining light and photosynthesis
• They use trunks
• Vines help to support, and gain energy
• Epiphytes use height
• Strangler epiphytes
• Herbaceous plants and shrubs help gain light

Niches

• Role within environment
• The use of a community which is the abiotic and biotic part

Fundamental Niche

• Range where species can survival and produce

Realised Niche

• Actual Condition which can exist in environment
• Interaction due to species

Competitive exclusion

• A community can only adopt by single animal
• Speices complete for resource and one survive more than the other
• Eliminate an species is competitive exclusion

The Four Community Dynamic

• Group interacting and exchange
• Investigation
• Study of species
• Area the population of habitat