Bio - Test 2

Natural disturbance

a naturally occurring event that causes significant mortality or damage to organisms or habitat; alters the structure, composition, and function of an ecosystem

Succession

how species composition & community structure change overtime, esp after disturbance

• Primary succession: on newly exposed site not previously occupied by soil & vegetation

• Secondary succession: on a site that already supported life but has undergone a disturbance (ie fire, tornado, farming, flood)

Recent extinction locations

Pacific islands lost native bird species after Polynesian settlement

Freshwater ecosystems - due to pollution, overfishing, and damming

Examples of deliberate & accidental introduction of invasive species

deliberate: house cats brought from Asia and Africa; now major invasive predator in many regions

accidental: fire ants introduced accidentally in firewood and agricultural products; now invasive in the US

One reason why water hyacinth is able to invade

forms dense mats on freshwater surfaces, which block sunlight and reduce oxygen levels -->

• decline of submerged native plants and aquatic animals

• its rapid growth allows it to outcompete native species for nutrients and space

• extensive root system absorbs large amounts of nutrients

What sorts of species are successful invaders?

• Rapid reproduction and growth

• broad environmental tolerance

• generalist diet and habitat use

• strong competitive abilities

• phenotypic plasticity

• dispersers that can travel across the new area to find suitable habitats

Transporting species to new areas

most species do not successfully invade & establish themselves

Species that do not successfully invade

• Species with a high reproductive rate under favorable conditions

• Generalist species with broad habitat requirements and diet

• Good dispersers that can travel across the new area and find suitable habitats.

Types of places that are likely to be invaded

• Not all places are equally vulnerable to invasion, but most likely:

1. Early successional/disturbed areas

2. Remote islands with low diversity

   1. Few species have been able to colonize naturally

   2. Communities and food webs are often simple with potential empty niche space to be exploited

   3. No predators and naïve prey

Example of an introduced pathogen & similarities/differences to other invasive species examples

a disease‑causing microorganism (bacterium, virus, fungus, parasite) that has been brought into a new geographic area, host population, or environment where it was previously absent

• Dutch elm disease: introduced to N America via infected wood products, now threatens American elms; microbial invader that can kill entire trees, unlike most plant or animal invasive species that are themselves the invader

• sim/diffs?

Transgenic organism & implications for invasive species

organism whose genetic material has been deliberately altered using biotechnology to add, remove, or change specific genes to introduce desired traits

implications for invasive species: enhanced competitive ability, disrupts natural ecosystem

Sustainable use

the use of species or natural communities in such a way that ensures they will remain in a “healthy” state and be available for use by subsequent generations

How does the biology of each species factor into sustainable use?

• Species with slow growth, long lifespans, and low reproductive rates (large mammals, slow-growing trees) are more vulnerable to overexploitation

• Don’t overharvest keystone species or ecosystem engineers (pollinators, large predators, certain trees)

r-selected species

• high rate of per capita population growth (r), but poor competitive ability

  • Grow quickly, reach reproductive age early (weeds, many insects)

K-selected species

• K-selected species: +/- stable populations adapted to exist at or near carrying capacity, K

  • Devote energy to growth & maintenance (elephants, whales)

  • Vulnerable in a human-dominated world

Examples of aquatic overexploitation

• Whaling moratorium and recovery, fisheries, coral reefs

What kinds of pets and plants are most sought after (pet trade & plant poaching)?

• Pets: Exotic species, especially birds

• Plants: Ornamental plants - rare plant poaching inc cactus, orchids; also dudleya (everlasting succulent)

Trade in animal parts & trophy hunting - examples

• Charismatic vertebrate species (tigers, lions, bears)

  • Rhino horns, elephant ivory

• Status symbols, traditional medicine

Overexploitation of what kinds of species can have many indirect effects?

Keystone species, top predators, ecosystem engineers

Exploitation of what shared abiotic resource can endanger specific species and entire ecosystems?

freshwater

protected area

• an area of land +/or sea dedicated to the protection & maintenance of biological diversity, & of natural and associated cultural resources

• managed thru legal or other effective means

What determines which areas are protected?

• level of biodiversity

• contain threatened or endangered species, critical habitats, unique ecosystems

• US Endangered Species Act: critical habitats are essential for conserving species

species richness

number of species in a community

relative abundance

how common a species is compared to others in the community

species diversity

combines the number of species and their relative abundance

Shannon diversity index

measures the species diversity of a community

Patterns of biodiversity and species richness

• Species richness

  • Increasing from polar → temperate → tropical areas

  • Increases w/ topographical variation

  • Decreasing along peninsulas away from large land area

Three hypotheses for latitudinal gradient in species richness

• Megadiversity countries: countries w/ greatest # of species

• Biodiversity hotspots: diverse & threatened (1500+ species of endemic vascular plants & loss of 70% of original habitat)

• Representative habitats: conserves some of every habitat (not just species-diverse ones)

• Last of the wild: protect areas w/ least human impact (intact ecological communities, even tho not always highly diverse)

diversity-stability hypothesis

• Species diversity & community stability

• Disturbances in a species-rich community would be cushioned by large #s of interacting species

• More drastic in less diverse communities

Indicator taxa (biodiversity)

• A taxonomic group (birds, mammals, flowering plants) that is easy to sample, well studied

• Patterns in its biodiversity used as an indicator or a surrogate of overall biodiversity

Taxonomic distinctiveness

• Measures the average taxonomic distance btw species in a community (how far back on fam tree you have to go for a common ancestor)

• Shows how evolutionarily spread out those species are

30 by 30 project

global conservation initiative aiming to protect 30% of Earth’s land and ocean by 2030

strengths and weaknesses of the protected area approach to conservation

• Strengths: Protects entire ecosystems & maintains biodiversity

  • helps prevent extinction

  • relatively easy to protect a set area as opposed to a species that might be spread out across the world

• Weaknesses: Only protects organisms in a specific area (leaves many other organisms vulnerable)

  • can have large edge effects, especially if far from other protected areas

Does the surrogacy approach to biodiversity assessment really work?

It can work, but def not always (often better than nothing and somewhat accurate, but not always a reliable form of measurement (depends on the situation))

What shape should reserves be? Why are they often not that shape?

• Ideal = circle bc minimizes edge effects

• Often not circles bc of land features (mts, river, etc), human presence (highways, etc), follows shape of natural habitat

When and why is management necessary?

1. Community is the result of long-term human activity

2. They are small fragments of the former ecosystem & therefore can’t support many of the species that formerly occurred

3. Isolated from other natural areas & the dynamics of colonization/extinction may not favor persistence of many species

4. Remnant areas will not experience the former frequency of natural disturbance (ie fires, floods)

5. Surrounded by a diff, fundamentally altered ecosyst, which may threaten the integrity of the area thru pollution or other disturbance

ex: Woodsman’s Butterfly (successful conservation in UK)

Single-species approaches

Protecting these often protects many others along the way

flagship

charismatic/culturally signif species (ie giant panda) used as a symbol to promote conservation awareness & funding

sentinel

species used as early warning systems to detect enviro hazards (toxic gases, pollutants, pathogens) (ie canaries in coal mines)

keystone

species has a disproportionately large impact on its ecosyst despite often being low in abundance

• Sea stars: Control mussel pops in intertidal zones, maintaining species diversity

umbrella

species whose large/complex habitat requirements mean that protecting it automatically protects many other species that share the same ecosystem

• Giant panda (bamboo forests in China)

How can one species occupy several categories (flag, sent, key, umb)?

categories describe different functions or strategic purposes rather than mutually exclusive ecological traits

Classes of rarity based on three parameters

• Geographical range: species confined to a small geographical range, but may be numerous where they occur

• Habitat specificity: may be geographically widespread but confined to very specialized habitats

• Population size: where a species occurs, there is always only a small population

minimum viable population (MVP) & challenges with estimating it

• smallest # of individs a species needs to persist over a defined period

• a tool in managing populations, based on two parameters set by the conservationist

  • probability of survival that is considered acceptable (100% probability of survival is not achievable)

  • the time period being considered

• Challenges: bad data, small pops are more vulnerable to fluctuation

Masked decline

decrease in the size/health of a population that isn’t immediately obvious bc the decline is hidden or offset by other factors

6th mass extinction

ongoing human‑driven loss of plant and animal species at rates far above natural levels, making it the latest in Earth’s history of major extinction events

Living Planet Index & how it can lead to over/underestimates of wildlife declines

• global biodiversity indicator that tracks trends in vertebrate populations

• average wildlife pop decline of 73% btw 1970-2022

Effective Population Size (Ne)

• size of an idealized pop that would experience the same amt of genetic drift or inbreeding as the real pop

• Differs from census population (N) - only includes individs capable of reproducing (not very old or young)

• Factors reducing Ne: large fluctuations generation to gen.; unequal sex ratio

Genetic bottleneck (examples & consequences)

• sharp reduction in pop size due to huge event (disease, hunting, enviro disaster, etc) that permanently reduces genetic diversity

• future gens are descended from a small, random sample of original gene pool

• ex: elephant seals

How can we use information on genetic diversity in conservation?

• Prioritize pops for conservation, detect isolation, gene flow, & centers of diversity

• low genetic diversity increases vulnerability to inbreeding, reduces reproductive success, and heightens the risk of extinction —> try to find diverse pops for more successful conservation

Isolation and gene flow —> implications for conservation

• Low gene flow → loss of any one pop is more serious

  • Total gene pool of the species eroded

  • Recolonization is unlikely

  • Hard to find similar donor population, success less likely

• High gene flow → loss of any one pop is probably recoverable

  • Total gene pool of the species hasn’t been eroded;

  • The site might be recolonized naturally bc mvmt btw sites has recently occurred

  • If not, the species can be re-established using a donor pop that is very similar to the original

How is isolation & gene flow related to speciation & hybridization, & can that affect conservation of certain species?

• Isolation reduces/stops gene flow, which can drive genetic divergence & speciation

• Hybridization can reintroduce gene flow btw distinct lineages

• Both processes have major implications for species conservation

Culture, religious practices, folk medicines

Nature, esp plants, is intimately integrated into culture, religious practices, folk medicines

eye of newt

old herbal code name for mustard seed

Many plants are poisonous but also used in rituals and medicines, why?

their harmful compounds can (in controlled or symbolic ways) provide therapeutic effects, psychological experiences, or symbolic meaning

Have you seen any poisonous but ritualistic plants in lab?

angel’s trumpet: hallucinogenic but can cause seizures & more

Foxglove is growing outside Tranquada Student Services Center, why might landscape designers have chosen to plant it there?

idk its cute

ex situ conservation and when is it necessary

• removal of individs/groups from their natural habitat into captivity, either to breed or to maintain a genetic stock

• Zoos & aquaria for animals, botanic gardens & herbaria for plants

• Necessary when species face immediate, severe threats in the wild that make survival in their natural habitat unlikely w/out human intervention

ex-situ v in-situ conservation

• In situ: protects species w/in their natural habitats (national parks, wildlife sanctuaries)

• Ex situ: protects species outside their natural habitats in controlled enviros(zoos, botanical gardens, seed banks)

What types of plant material are conserved ex situ?

• seeds - seed banks!

• pollen - less common; freeze dried

• tissue - effective in species that exhibit clonal growth & normally reproduce vegetatively (potato, banana)

Captive breeding programs: advantage and challenges

Advantages:

1. Increasing pop size for re-establishment in wild

2. Enables research on basic biology of species

3. Can eventually reduce need to collect individuals from the wild

4. Captive colonies can be used to educate the public abt the species

Challenges:

1. Initial source of stock: can endanger remaining small wild pops

2. Facilities for breeding: needs zoos & aquaria

3. Maintaining a large enough population

4. Captive pops may undergo selection & adapt to their captive conditions; loss of learned behavior

5. Susceptibility to disease due to artificially high concentration of individs

6. Can be difficult to get species to breed under captive conditions

Species reintroductions, translocations, & population reinforcement (examples & goals, mixed track record)

Reintroduction: reintroduce species to their natural habitat in self-sustaining (viable) pops

• Attention-grabbing → raises awareness, but very difficult & expensive

• Ex: black-footed ferret - all ferrets captured from wild, then breeded & released; increased the pop but lack of learned behaviors (couldn’t hunt well or avoid predators)

Translocation: moving individs from one location to another

• Useful in fragmented landscapes where many pops are isolated from each other

• Good if new individuals are from the same species bc decreased risk of inbreeding & bad recessive traits; can introduce good genes

• Bad if new individs are from diff species bc might not be able to produce fertile offspring (can only produce hybrids that’re diff from the species conservationists are trying to save)

• Ex: American bison in Montana

Population reinforcement: intentional addition of individs to a small, declining, or genetically vulnerable wild pop to improve its size, genetic diversity, & long-term viability

• Risks: hybridization w/ unrelated pops, low survival, impact on ecosystem, expensive

• Ex: CA condors - raised birds in captivity & slowly released them

What are some plants we learned about in lab? Did we learn about any plants that showed up in lab and lecture?

• Lecture & lab: orchids (rare plant poaching & hard to collect seeds for seed banking)

What is phenology? What are phenological phases in plants?

Phenology: study of cyclic & seasonal natural phenomena, esp in relation to climate & plant/animal life

Phen phases in plants: timing of recurring biological events (bud break, leafing, flowering, fruiting, leaf fall) & how these events are influenced by seasonal climate factors (ie temp, rainfall, day length)

What is an herbarium? Benefits and challenges to seed banking?

Herbarium: preserved collection of plant specimen w/ detailed data on its identity, location, date, habitat, & more

• Benefits: keeps track of plants, accurate representation of plants; species monitoring

• Challenges: data gaps, stored plants might no longer exist in wild, preservation & access issues