Unit 5 - Biology

species

A group of similar organisms capable of breeding and producing fertile offspring

variation

Differences in any aspect of an organism

classification

A system of organising knowledge on all living things based upon their characteristics and more recently their DNA

binomial nomenclature

Naming system for living organisms using two names for each species; the genus followed by the species

sexual dimorphism

When the male and female of a species look significantly different. Often having completely different features and appearance

interbreed

Breeding between species. Produces infertile hybrid offspring

hybrid

The result of breeding between members of two different species; usually infertile

speciation

The formation of new species by the splitting of one pre-existing species into two or more new species

population

A group of organisms of one species, living in the same area at the same time

biodiversity

The variety of life on Earth, or in a particular habitat or ecosystem

Inbreeding

Breeding between closely related individuals

genetic diversity

The diversity seen in the genes (alleles) within a population of a species

species diversity

The number and types of organisms that existed during a specific amount of time

ecosystem diversity

Variety in ecosystems in a given area

community

A group of interacting species in a particular environment (for example, a forest – with its trees, plants, animals, bacteria and fungi)

dichotomous key

A tool used to identify species found in the field based on observations. A series of questions with two possible answers that leads to the correct identification of a species

DNA barcoding

A method of environmental sampling that allows for the identification of species and the determination of biodiversity from traces of DNA

anthropogenic

Relating to humans and human activity

megafauna

Very large animals that exist in a particular area, habitat or geological period

habitat

The place in which a community, species, population or organism lives

ecosystem

A community of living organisms and its abiotic (non-living) environment

biome

Communities of living organisms spread over a large geographical area. They are often named based on the dominant vegetation

biotic

The living components of an environment, such as plants and animals

abiotic

The non-living components of an ecosystem

symbiotic

A relationship between two or more organisms in which the presence of each organism helps the other organism to survive and thrive

convergent evolution

Pattern of evolution where distantly related organisms evolve similar traits in response to environmental similarities

ecological niche

The role of a species within an ecosystem or community and its interrelationships with both biotic and abiotic factors

obligate anaerobes

Organisms that can only survive in environments that lack oxygen

obligate aerobe

Organisms that can only survive in environments that contain oxygen

facultative anaerobe

Organisms that can survive in environments that contain or lack oxygen

autotroph

An organism that can produce its own chemical energy using light, inorganic compounds or other energy sources (also referred to as Producers)

heterotrophic

Organisms that cannot produce their own food, consumers; they must ingest nutrients from other organic sources (also referred to as Consumers)

holozoic

Organisms that consume food via the process of ingesting, digesting and assimilating the nutrients

mixotrophic

An organism that can use a mix of different sources of energy and carbon, instead of having a single trophic mode on the continuum from complete autotrophy at one end to heterotrophy at the other

saprotroph

Organisms that obtain nutrients by secreting digestive enzymes followed by absorbing and assimilating the nutrients

decomposer

Organisms that break down dead matter into simpler substances

Archaea

A domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. They are known for their ability to live in harsh environments

chemoautotrophs

An organism that derives energy from the oxidation of inorganic compounds via chemosynthesis

photoautotrophs

An organism that can make its own energy using light and carbon dioxide via the process of photosynthesis

hominids

A primate of the family Hominidae that includes humans and their fossil ancestors including some of the great apes (such as gorillas, chimpanzees, and orangutans)

herbivore

An organism that obtains its nutrition by consuming plants or plant material

carnivores

An organism that relies on eating other organisms for nutrition

omnivores

An organism that is adapted to eat both plant and animal material for nutrition

predator

Organism that kills and consumes other organisms

prey

An organism that is hunted, captured and consumed by another organism (predator) as a source of food

parasitism

Relationship where one species benefits and the other is harmed

mutualism

Relationship where both species benefit

commensalism

A relationship where one organism benefits without affecting the other

competition

Interaction between organisms competing for the same limited resource

proboscis

An elongated sucking mouthpart found in insects that is typically tubular and flexible

phytochemicals

Chemical compounds produced in plants

epiphytes

Plants that grow on the surface of other plants using them only for support. For example, orchids

lianas

A climbing plant common to tropical rainforests. They have long winding aerial roots that enable them to climb trees of the rainforest

fundamental niche

The range of environmental conditions in which a particular species can live

realised niche

The environmental condition in which the species actually lives

competitive exclusion principle

States that if two species with identical niches compete, then one will inevitably drive the other to extinction

niche/resource partitioning

The process by which competing species use the environment differently in a way that helps them to coexist. This may be spatial or temporal

carrying capacity

The maximum number of individuals of a species an environment can sustain

reproductive isolation

A mechanism that prevents individuals of different species from mating and producing viable offspring

geographical isolation

The physical separation of populations of a species by geographic barriers, such as mountains, rivers or oceans, which restrict gene flow between populations

behavioural isolation

Type of reproductive isolation in which differences in behaviour, such as mating rituals or courtship displays, prevent individuals from breeding

temporal isolation

Type of reproductive isolation in which individuals of the same species have different mating seasons or times of reproductive activity, preventing them from breeding with individuals from other populations

random sampling

A method of selecting a subset of individuals from a larger population in a way that each individual has an equal chance of being selected

quadrat sampling

Sampling technique in which a quadrat, typically a square or rectangular frame, is placed in a specific area to study the distribution and abundance of organisms within that defined area

quadrat

A square or rectangular frame used for sampling in ecological studies

total abundance

The total number of organisms in all species in an area

sessile

An organism that is fixed to one location

motile

An organism that is able to move its whole body from one location to another

food chain

Feeding relationship where energy passes from producers to consumers

food web

A network of interconnected feeding relationships

keystone species

A species with a disproportionately large effect on its community

domain kingdom phylum class order family genus species

Levels of classification (name all)

Population

A group of organisms of 1 species, living in the same area at the same time

Speciation

Formation of new species by the splitting of one preexisting species into 2 or more new species

• Possible causes for species splitting:

  • Reproductive barriers limiting/preventing interbreeding between 2 populations

  • Physical barriers prevent interbreeding

  • Change in behavior/timing around reproductive cycles

  • Sudden event changes chromosome number, resulting in new species (errors in cell division)

• Occurs gradually (take long time after physical splitting of population), with populations slowly showing different traits from selection pressure ---> becoming more and more isolated --> less likely to gene flow --> more clear differences between the populations --> formation of new species

• Possible causes for species splitting:

  • ________ barriers limiting/preventing _______ between 2 populations

  • Physical barriers prevent interbreeding

  • Change in _____/timing around reproductive cycles

  • Sudden event changes chromosome number, resulting in new species (errors in cell division)

• Occurs ___quickly/gradually____ (take long time after physical splitting of population), with populations slowly showing different traits from selection pressure ---> becoming more and more isolated --> less likely to _____ flow --> more clear differences between the populations --> formation of new species

Karyotyping

Isolating condensed chromosomes taken from actively dividing cells, allowing for comparison of chromosomes

DNA barcoding

Unknown specimen/environmental sample, often water or soil, is collected and DNA is extracted. From the sample, certain specific sequences are identified, creating a unique "barcode" for the specimen

Pros and Cons of eDNA:
Pros: Non-invasive, can detect rare/cryptic species, rapid assessment of large areas cheaply

 

• Cons: DNA degrades, inaccurate gauge of population sizes, potential contamination, won't identify any species not in the database.

Pros and Cons of eDNA:
Pros: Non-_______, can detect ____/cryptic species, _____ assessment of large areas cheaply

 

• Cons: DNA degrades, inaccurate gauge of population _____, potential ___________, won't identify any species not in the database.

Biodiversity

Variety of living organisms, including plants, animals, and microorganisms. Occurs in 3 levels: Genetic, species, and ecosystem.

Genetic, species, ecosystem

Levels of biodiversity: (3)

Genetic diversity

Variation of existing genes between individuals of a population, caused by variations in the genes

Species diversity

Variety of species seen in a particular habitat, which influences species diversity. Result of the community of organisms (the biotic) and their interaction with the abiotic environment

species richness and species evenness

Species diversity depends on 2 factors:

Ecosystem diversity

Variety of ecosystems (both terrestrial and aquatic) found in a given geographical area

Ecosystem

Community of organisms and their interaction with the abiotic environment, varying in size.

• overexploitation from overhunting and overharvesting

• habitat destruction

• invasive species

• pollution

• climate change

Causes of anthropogenic species extinction (5)

Giant moas and carribean monk seal

2 Case studies of anthropogenic species extinction: (2)

Ecosystem Services

The processes and outputs of the ecosystem that directly or indirectly benefit humans.

• Supplying resources (water, food, timber, medicine)

• Providing basic services essential for survival

Keystone species

A species that plays a critical role in maintaining the structure and functioning of an ecosystem. The presence or absence can significantly impact the overall biodiversity and stability of the ecosystem

Dipterocarp trees and coral reefs

2 case studies of ecosystem services:

IPBES and IUCN

2 databases to identify biodiversity crisis:

In situ conservation

• Way of conserving animals and plants in their natural habitat whilst maintaining the original biodiversity of the area

• Involves designing, managing, and maintaining areas for the protection of plant and animal species

• Conserves plant/animal species AND their habitat

• Preserves normal behavior

• Prevents disruptions of the food chains

• Cost efficient

Ex situ conservation

• Plants/animals conserved outside natural habitats

• Include zoos, botanical gardens, aquariums

• For some species, numbers are too small to sustain species, or risk of poaching is high = Gene banks to store "biodiversity" = storage of germplasm

• Seed banks: Dehydrate and cool seeds prior to storage

• Tissue banks: Store tissue samples from plants

  ex

Captive breeding

○ Conservation technique for preventing the extinction of species whose populations are small, fragmented, and on the verge of extinction

○ Encouraged to breed + reintroduced into the wild

○ BUT, small populations = lower genetic diversity = Increased chance of passing on unfit genes

Ex. Arabian oryx: Antelopes existed in zoos, which captive breeding ensured species could be released into the wild

Rewilding

○ Conservation technique by which wildlife and natural processes are allowed to reclaim areas, bringing back biodiversity

○ Habitat is restored to what it would've been if human disturbance hadn't happened

Rewilding happens with human intervention, as plant/animal species that have disappeared from the habitat are reintroduced = Helps rebuild ecosystems

Reclamation of degraded ecosystems

land restoration and management with support from local communities and indigenous people yields higher results as they have a deep knowledge of the land

Evolutionarily Distinct and Globally Endangered

EDGE stands for:

Habitat

Place where an organism/group of organisms lives and interacts with its surroundings

• Geographical or physical location that provides the necessary resources for an organism's survival and reproduction

• Consists of biotic and abiotic factors

Adaptation

Genetic change that increases an organism's chances of survival + reproduction in a particular environment

• Can occur randomly via mutation or via selective pressures

• Developed to cope with physical/abiotic conditions of habitat (ex. Temp, moisture, light)

Natural selection

Mechanism that drives the spread of beneficial genetic mutations throughout a population

• Individuals with advantageous traits more likely to survival and pass on genes to next generation

• Over time, advantageous traits become more common in population