IB Biology HL review (with IB command terms)

Define Habitat

A place in which an organism, species, population, or community exists

Outline the adaptations of Lyme grass to its environment

Thick waxy cuticle on leaves reduces transpiration

Stomata in indentations to protect humid air during high winds

Leaves can roll up during droughts

Touch sclerenchyma to protect from wilting during droughts

Rhizomes that grow upwards as sand accumulates and extent deep in the dune to reach water

Accumulation of carbohydrates, fructans, in the root and leaf cells to increase osmotic potential

Outline the adaptations of Mangrove Trees to their environment

Secretion of excess salt from salt glands in the leaf

Root epidermis covered in suberin (Cork) which reduces permeability of salt

Cable roots growing close to the oxygen-rich soil surface

Pnematophores which are vertical roots that grow up into the air and absorb oxygen

Stilt roots that grow out in an arch from the trunk of the tree and buttress it

Large buoyant seeds

Accumulation of mineral ions and carbon compounds (mannitol) which increases the osmotic potential of leaf and root cells

List the abiotic factors that determine animal species distribution

Water availability and temperature

List the abiotic factors that determine plant species distribution

Temperature, water availability, light intensity, soil pH, soil salinity, and the availability of mineral nutrients

Define Range of Tolerance

A range of environmental factors in which an organism can survive in according to their adaptations to their environment

Outline the different ways to use Transects to investigate tolerances ranges of organisms

Line Intercept Sampling - a tape is laid along the ground between two poles and all of the organisms touching the line are recorded

Belt Transects - the abundance of a species is estimated in the area between two lines separated by a fixed distance

Observational Transects - the observer walks along the defined route and a defined pace and counts organisms

Outline the advantages of using data logging to monitor environmental conditions

Less expensive and easy to operate

Designed to be compact and powered with battery power

Available for measuring hundreds of parameters

Can take repeated measurements rapidly

Can be left to take measurements automatically for long periods of time

Store data can be transferred easily to computer

List the conditions required for Coral Reef formation

Less than 50 m deep

pH above 7.8

Salinity between 32-42 ppt (parts per thousand) of dissolved ions

Clear water, low turbidity

Temperature between 23-29 degrees C

Define Biome

All ecosystems of a specific type, characterized by similar temperature and rainfall patterns

List the abiotic conditions of the Tropical Forest biome

Temperature - high

Precipitation - high

Light Intensity - high

Seasonal Variation - minimal

List the abiotic conditions of the Temperate Forest biome

Temperature - medium

Precipitation - medium/high

Light Intensity - medium

Seasonal Variation - warm summers/colder winters

List the abiotic conditions of the Taiga biome

Temperature - low

Precipitation - medium/high

Light Intensity - medium/low

Seasonal Variation - short summers/long cold winters

List the abiotic conditions of the Hot Desert biome

Temperature - high

Precipitation - low

Light Intensity - high

Seasonal Variation - minimal

List the abiotic conditions of the Grassland biome

Temperature - medium/high

Precipitation - medium

Light Intensity - medium/high

Seasonal Variation - variation with a dry/cold season

List the abiotic conditions of the Tundra biome

Temperature - low

Precipitation - medium/low

Light Intensity - low

Seasonal Variation - very short summer/very cold winter

Outline the adaptations of the Saguaro cactus to its environment (hot desert)

Wide spreading root system to collect water 30 m deep

Deep tap roots to collect water from subsoil

Fat stems with water storage tissue

Pleated stems that allow shrinking in droughts and expanding after rainfall

Vertical orientation of stems to minimize sunlight during midday and maximize it during cooler times of day

Thick waxy cuticle on stem epidermis to reduce transpiration

Leaves reduced to spines to reduce transpiration and prevent herbivory

CAM metabolism allowing stomata to open at night and close during the day

Outline the adaptations of the Fennec fox to its environment (hot desert)

Nocturnal to avoid high temperatures

Underground den to stay cool during the day

Long thick hair for heat insulation for cold nights and hot days

Hairs covering feet pads to protect from hot sand

Pale coat to reflect sunlight

Large ears that radiate heat

Variable ventilation rate which can increase to cause heat loss by evaporation (panting)

Outline the adaptations of the Meranti tree to its environment (tropical rainforest)

Grows to over 100 m tall to avoid light competition

Hard dense trunk for support during strong winds

Trunk buttressed at the bottom

Smooth trunk to shed rainwater rapidly

Broad oval leaves with pointed tips to shed rainwater rapidly

Evergreen leaves which photosynthesize year-round

Enzymes of photosynthesis adapted to function at high temps (35C)

Flowers and seeds produced in large quantities some years, and small amounts others to reduce herbivory

Outline the adaptations of the Spider monkey to its environment (tropical rainforest)

Long arms and legs for climbing and reaching fruit

Flexible shoulders for swinging

Large hook-like hands for grasping branches and vines

Feet that act like extra hands

Tail that can act like fifth hand

Highly developed larynx to communicate in dense rainforest

Sleeping at night and active during daytime for optimal vision

Breeding at any time of year due to constant supply of food

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Define Ecological Niche

The functional position and role of an organism within its environment. Consists of all biotic or abiotic interactions that influence growth, survival and reproduction. No two species can have the same niche.

Outline the result of two species competing for a shared ecological niche

Competitive exclusion - one species uses the resources more efficiently, driving the other species to local extinction

Resource partitioning - both species alter their use of their habitat to divide resources between them (niche separation)

Differentiate between fundamental niches and realized niches

Fundamental niche - the entire set of conditions in which can organism could survive

Realized niche - the set of conditions used by the organism after including interactions with other species

Define Obligate Aerobes

Organisms that cannot survive in the absence of oxygen and rely on aerobic respiration to produce ATP

Differentiate between Obligate Anaerobes and Facultative Anaerobes

Obligate Anaerobes - Single-celled organisms that cannot survive in the presence to oxygen (found oxygen-free environments like in deep sea, lower levels of soil, or within the bodies of certain organisms)

Facultative - Organisms that normally respire aerobically, but can switch to anaerobic respiration in the absence of oxygen (yeast, Ecoli)

Define Autotroph

An organism that synthesizes organic compounds from inorganic substances

Define Photoautotroph

Organism that derives energy from the synthesis of organic compounds from sunlight (photosynthesis)

Define Chemoautotroph

Organism that derives energy from the synthesis of organic compounds from the oxidation of inorganic chemicals (chemosynthesis)

Define Heterotroph

Organism that obtains organic molecules from other organisms

Define Holozoic Nutrition

Ingesting organic compounds and internally digesting the consumed material

Define Saprotrophic nutrition

Releasing enzymes to digest organic compounds externally and then absorbing the products

Outline the three main categories of Archaea

Phototrophs - use light energy to produce ATP, but they do not undergo photosynthesis or produce oxygen

Lithotrophs - use a variety of inorganic compounds to produce ATP

Organotrophs - use organic compounds to produce ATP, obtained via heterotrophic nutrition

Define Mixotroph

Organisms that can use both autotrophic and heterotrophic modes of nutrition, can be obligate or facultative

List examples of mixotrophic nutrition

Unicellular organisms, Euglena (protists) and Dinoflagellates (plankton)

Coral

Carnivorous plants, Venus fly trap

Outline the ways that plants adapt to harvest light

Lianas - Woody vines that climb on other trees to reach the canopy

Overstory - Trees grow taller than the canopy

Understory - Low-growing herbs and shrubs possess large leaves to maximize surface area

Shade Tolerant Plants - Contain different pigments for photosynthesis to absorb more wavelengths of light

Epiphytes - Plants that grow on the branches of other plants (can be strangler epiphytes, which grow roots into the soil and compete with the host for resources)

Outline the three categories of Holozoic Nutrition

Consumers - feed on living or recently killed organisms

Scavengers - feed on dead or decaying carcasses rather than hunting prey

Detritivores - feed on non-living organic matter, such as detritus or leaf litter

Outline plant adaptations to reduce herbivory

Physical Structures - spines and thorns act as deterrents, thick bark and waxy cuticles restrict ingestion

Chemical Compounds - seeds and leaves may have toxic or bitter-tasting compounds

Outline herbivore adaptations for feeding on plants

Specialized mouthparts - beetles have jaw-like mouthparts for biting and chewing, and aphids have tubular mouthparts for piercing and feeding on sap

Digestive systems - animals have multiple components in their stomach to allow the regurgitation and breakdown of food

Microbiotic bacteria - helps break down plant sugars

Metabolic processes - animals produce chemicals capable of neutralizing toxic chemicals

Outline prey adaptations to resist predators

Physical Structures - tough exoskeletons and shells

Appearances - may be camouflaged, mimic predator structure, or processes bright warning colors

Chemical Compounds - toxins and scents may deter or harm predators

Behaviors - feigning death, puffing up, or grouping together to avoid predation

Outline predator adaptations for catching prey

Physical Structures - sensory organs to better detect prey and features such as sharp teeth and claws

Appearances - may be camouflaged or have a streamlined body

Chemical Compounds - neurotoxins and venoms can be used to paralyze and subdue prey

Behaviors - may lay in ambush or hunt in packs to catch prey

Define Hominidae

A family of greater apes that include gorillas, chimpanzees, and humans

Outline the relationship between dentition and the diet of members of the Hominidae family

Hominids that mostly feed on plant matter have broader jaw muscles, large premolars, and thick enamel

Hominids that feed on more meat have narrower jaws and smaller teeth, incisors and canines

The kind of teeth an animal has tells people what kinds of things they eat

Outline the requirements for stability in an ecosystem

Recycling of nutrients

Abiotic conditions must remain inside tolerance limits

Genetic diversity high

Energy supply consistent

(RAGE)

Define Mesocosm

An enclosed environment that allows a small part of an ecosystem to be observed under controlled conditions

Can be set up with a known factor altered to assess its effect

Define Keystone species

A species that has a disproportionately large impact on the environment relative to its abundance, prevents ecosystem from collapsing

List examples of Key stone species

Sea otters - exert top-down pressure on sea urchins which graze on kelp, preventing urchin overpopulation and kelp destruction

Honey bees - pollinate a wide variety of species

Beavers - build dams that transform environment

Define Sustainable Yield

The amount of natural resources that can be taken from an ecosystem without reducing the base stock

Outline the factors affecting sustainability of agriculture

Supply of fertilizers - organic fertilizers > chemical

Carbon footprint - land clearing, fertilizer production, and transportation of products increase carbon footprint

Agrochemical pollution - herbicides/pesticides harm native species

Leaching of nutrients - rainfall washes fertilizers into bodies of water, leading to eutrophication (killing plant and fish life)

Erosion - removal of trees makes the land less stable

Outline the effect of deforestation in the Amazon

If Amazon reaches a tipping point of deforestation:

The removal of trees will cause temperature and rainfall changes

Temperature and rainfall are critical factors for photosynthesis and nutrient cycling

Define Rewilding

Involves the use of conservation strategies to restore ecosystems to their natural conditions

Outline Rewilding strategies

Species reintroductions - keystone species and apex predators can control consumer populations and improve biodiversity

Improve habitat connectivity - wildlife corridors between habitats allows organisms to occupy larger areas and access more resources

Minimize human activity

State an example of Rewilding working

Hinewai Reserve in New Zealand

Define Ecological Succession

Describes the progressive change in the structure of a biological community over time

Outline the changes that can trigger ecological succession

Climate factors (wind, fire, natural disasters, erosion)

Changes to the activity of organisms (aggregation, migration, and competition)

Distinguish between primary and secondary succession

Primary - the development of a new ecological community in an environment without previous life

Secondary - the development of a new community following the disruption of a previous community

Outline the steps of primary succession

Pioneer species colonize (usually lichen or moss)

Intermediate species colonize (plants that change soil depth and mineral content

Larger plants are able to grow

Climax community is reached when succession is ended and the community has all of its characteristics

Define cyclical succession

When a climax community is not stable and is regularly and repeatedly replaced (caused by recurring events or changing interactions between animal and plant species)

Define arrested succession

When humans interfere with the succession process by altering environmental conditions, preventing climax communities from forming or creating alternative habitats

Define Phenology

The study of the timing of biological events and how these are influenced by seasonal variations or habitat factors

Outline examples of phenology

The seasonal development of buds (bud set) and the subsequent emergence of new leaves (bud burst)

The blooming of flowers to coincide with the activity of pollinators or weather conditions conducive to pollination

Migration of birds in concordance with annual changes in climate

The timing of nesting to ensure that eggs hatch during a time with abundant resources

The suppression of metabolic activity during winter months to limit energy expenditure in cold climates

Outline the disruption of phenological events due to climate change

Climate change alters environmental cues that trigger the events (mostly temperature and sunlight during a day, photoperiod)

Outline the impact to the number of insect life cycles within a year due to Climate Change

Life cycle of the Spruce Bark Beetle is regulated by temperature

Climate Change is increasing the number of life cycles per year causing the beetles to feed on and damage more trees

Outline evolution as a consequence of climate change

Climate Change affects the environmental pressures that drive natural selection, different traits become more common that help them better survive in a new environment

Define Eutrophication Out

The enrichment of of an ecosystem when chemical nutrients

Outline the consequences of eutrophication of bodies of water

Algal blooms occur rapidly

As algae dies, saprotrophic microbe populations spike, leading to an increased oxygen demand

Water is deoxygenated, turbidity I'd increased, killing plants and fish

Define Biomagnification

The process in which chemical substances become more concentrated at each trophic level

This is because organisms at higher levels must consume more biomass to meet requirements

Distinguish between macroplastics and microplastics

Macroplastic - debris >1mm

Microplastic - debris <1mm

Both are ingested by marine animals

Outline the greenhouse effect

Sun emits short wave radiation- absorbed by earth and re-emitted in long form radiation

Greenhouse gasses in the atmosphere reflect that light back down on earth, heating the planet

Outline the main anthropogenic cause of climate change

Increased combustion of fossil fuels, leading to higher levels of CO2 in atmosphere

Leads to greenhouse effect

Outline the 4 positive feedback cycles that contribute to climate change

Oceans as carbon sink - CO2 in water becomes less soluble as the water heats up, leading to more CO2 being released as temps rise

Loss of reflective ice/snow - light colored surfaces have a higher albedo (they reflect more light) than rock or soil. When ice melts, rock is exposed, leading to more temperature absorption.

Decomposition of permafrost - permafrost (ground that is frozen for two or more years straight) melts and exposes matter. The decomposition of matter releases CO2 and the melting of the permafrost releases methane.

Droughts/fires - higher temperatures increases the likelihood of droughts, which increases the likelihood of fires, which release more CO2 in the atmosphere

Outline the example of the Boreal Forest as a carbon sink

Boreal Forest has a decomposition rate lower than its photosynthesis rate - carbon sink

Increasing temps and less snowfall increases the rate of decomposition, and less water availability and droughts decreases photosynthesis

Could trigger tipping point, where climate change is irreversible

Outline how polar habitats are affected by climate change

Melting ice creates less space for emperor penguins to lay their eggs and raise their young - leading to decreased populations of penguins

Arctic ice used to provide a space for walruses to nurture their young next to the ocean. Now they have to nurture them farther from the ocean, leaving them unprotected

Outline poleward and upslope range shifts

Range shift - when species must migrate to new locations due to their previous locations falling outside of their range of tolerance

Poleward - shifts towards the poles, creating more competition for native species there

Upslope - shifts to higher elevations

Outline the impact of climate change on nutrient upwelling

Nutrient upwelling - when colder nutrient-rich water from lower down rises to the surface of oceans

When ocean temps rise, it prevents upwelling and decreases ocean primary production, compromising ecosystem stability

Outline the process of coral bleaching

Coral and zooxanthellae have a mutualistic relationship (coral gives algae protection, algae gives coral nutrients)

Higher temperatures lead to the explosion of zooxanthellae and prevent coral from reproducing

This results in coral bleaching

Outline the process of ocean acidification and its effect on coral reefs

Most CO2 absorbed by oceans combines with water to make carbonic acid which dissociates into hydrogen carbonate ions and protons (lowers pH of water)

Free carbonate ions will bind to protons to reduce the effect of the acidification, but this reduces the availability of carbonate ions, which are necessary for Coral Reef exoskeleton production

Define carbon sequestration

The process of capturing and storing carbon dioxide from the atmosphere into carbon sinks

List methods to increase carbon sequestration in forests

Forest regeneration - planting trees in deforested regions

Afforestation - planting new forests

Differentiate between discreet and continuous variation within populations

Discrete - traits that can be organized into specific categories (blood type)

Continuous - traits that fall on a spectrum (height or body weight)

Outline the binomial system of nomenclature

Formal system under which all species are classified

Consists of two names, genus and species (Homo sapiens)

Define species (according to the biological species concept)

A group of organisms that can interbreed and produce fertile offspring

Outline the problems with the biological species concept

Populations that are reproductively isolated from the rest of the species can diverge into a new species (speciation)

Asexual organisms

Sometimes genetic compatibility cannot be confirmed due to distance between populations

Ring species

Outline the hypothesis that humans diverged from chimpanzees during a fusion event

Chromosomes 12-13 on chimpanzees merged to form human genetic code

Combined length of 12-13 matches the length of human chromosome 2

The centromere location on human chromosome 2 matches matches chromosome 12

Human 2 contains telomere information where 12-13 would have fused together

Define Karyotyping and outline the process

The process of pairing and ordering the complete set of chromosomes in a cell to get a snapshot of an organisms genetic profile (karyogram)

Chromosomes become visible during mitosis, cells strained and put on slide and burst to spread chromosomes

Chromosomes are organized in pairs according to size, banding pattern, and position of the centromere

Can be used to determine species, sex, and if there are any chromosomal abnormalities

Define Genome

The totality of genetic information within an organism

Describe the comparison of genome sizes between species

Genome size varies significantly between species

Viruses and bacteria have small genomes, while eukaryotes have larger genomes

The size of a genome is not always an indicator of the organisms actual size

Some organisms can have a small genomes but a large number of chromosomes and vice versa

Define Single Nucleotide Polymorphism

A mutation that affects a significantly large percentage of the population >1%

Define Whole Genome Sequencing

The process of determining the DNA sequence of an organism’s entire genome at one time using a sample of DNA (hair, saliva, blood)

Outline the applications for whole genome sequencing

Can be used to determine ancestral relationships

Predict disease predispositions and create personalized medicine

Define DNA Barcode

Short section of DNA distinct enough to ID species

Define Dichotomous Key

A method of identification where where groups of organisms are divided into two categories repeatedly. Each division reveals more information about the species.

Define Clade

Every organisms evolved from common ancestor included in same taxonomic group

Define Synapomorphy

Shared traits with a common ancestor

Outline the process of creating a Cladogram

Computers do sequence analysis

Uses base sequences of genes or amino acid sequences of proteins - differences can be used to calculate how long ago species diverged

Uses principle of parsimony (looking for the simplest solution)

Outline how you would analyze a Cladogram

Branches represent individual clades

Branching points (nodes) represent hypothetical common ancestor

Base of the cladogram is the root

Outline examples of using cladograms to investigate classification

Figwort family - had a lot of organisms sorted into it, used chloroplast DNA to investigate the relationships between organisms leading to major reclassification

Mustelidae family (weasels, badgers, and otters) - same thing

Outline the three levels of biodiversity

Ecosystem diversity - variety the habitat types within a within a given area

Species diversity - variety of different species found within a particular habitat or ecosystem

Genetic diversity - the variety of genes and characteristics within one population

State how many mass extinction events there have been and when the last one was

5 mass extinction events

Last one was 66 million years ago

Outline the anthropogenic causes of species extinction

Overharvesting - hunting, harvesting, logging, and fishing at a faster rate than a species can reproduce

Habitat destruction - agriculture and the construction of towns and cities

Invasive species - non-native species introduced drive out endemic species and endemic species can hybridize with aliens

Pollution - self explanatory

Climate Change - species cannot adapt fast enough to keep up with abiotic changes due to climate change

List the causes of ecosystem loss

Land use change for agricultural expansion

Urbanization

Overexploitation

Mining and smelting

Building of dams and extracting of water for irrigation

Drainage or diversion of water

Eutrophication

Climate Change