UNIT 6 BIOLOGY

ecology and carbon cycle

biomass

biomass

total dry weight of organic matter in organisms or ecosystems

abiotic factor

non living factor eg) rocks, soil, light

biotic factor

living factor eg) other organisms

habitat

place where an organism or group of organisms lives and interact with its surrounding

Ecosystem

biotic and abiotic factors and their relationships with the area

Marram grass adaptations: tolerance to drought

deep roots allow access to water and nutrients during long periods of drought

Marram grass adaptations: tolerance to salt

high levels of salt in sand

Marram grass adaptations: root

strong or anchoring to resist erosion from wind or waves

Marram grass adaptations: leaf

strong and leathery rolled shape stomata tucked in curved side reducing water loss (transpiration)

Marram grass adaptations: sandbinding

traps sand particles in roots and stems to prevent erosion

Marram grass adaptations: Rhizomes

horizontal underground stems that grow bellow surface allows anchor and spread access water and nutrients and stabilise dune

Mangrove adaptations: Salt Tolerance

can tolerate high salinity levels in its habitat. leaves have mechanisms to excrete excess salt, preventing damage to sensitive tissues.

Mangrove adaptations: Aerial Root Systems

Roots emerge from the base of the trunk and extend above the water. Allow plant to breathe in oxygen even when submerged during high tides. helps it survive in the anaerobic conditions of mangrove swamps

Mangrove adaptations: Viviparous Propagules

develops green, cigar-shaped propagules within the calyx of its flowers. These propagules grow into new plants while still attached to the parent tree. Ensures successful reproduction in the challenging intertidal environment.

Mangrove adaptations: Bird-Pollinated Flowers

Large, pale yellow-green to pinkish-orange flowers attract birds. When probed by a bird, the petals release pollen explosively over the bird’s head, aiding in cross-pollination and reproductive success

Adaptations of Plants: Light

insufficient light: ferns and shade tolerant trees grow larger and thinner leaves and increase chlorophyll content to maximise light absorption

Adaptations of Plants: Light 2

too much light: succulents and cacti have thicker waxy skin that helps them retain water and reflect sunlight

Adaptations of Plants: temperature

extreme high: tomato plants have developed heat stock proteins to protect agains high temps

Adaptations of Plants: water

inadequate supply: during drought rice plants reduce water loss by closing their stomata

Adaptations of Plants: Soil

poor soil quality: legumes have developed symbiotic relationships with nitrogen fixing bacteria to obtain nitrogen from air

Adaptations of Animals: Temperature

extreme temps: polar bears + penguins have thick layers of fur or blubber to insulate from extreme cold

Adaptations of Animals: water

fluctuations in water level: camels + kangaroo rats store water in their bodies to survive dry environments

Adaptations of Animals: light intensity

changes in light: bats and owls are active at night to avoid predators and to take advantage of night active prey

Adaptations of Animals: Food

changes in food supply: herbivores adapted to have specialised teeth or digestive systems to extract nutrients from tough plant

Adaptations of Animals: Climate

climate patterns: bats + ground squirrels hibernate during winter months to conserve energy and survive colder temps

Type of Transect: REA

Rapid ecological assessments —> used to quickly document what species are present at a specific location

Type of Transect: BLT

Belt transects —> mainly used to count high numbers of small and abundant fish

Type of Transect: SPC

Stationary Point Counts —> used to count larger (<25cm total length) and more active fish species

Type of Transect: TDVS

Towed-Driver video Surveys —> used to count larger (<50cm total length) and more active fish species

Conditions for Coral Reef Formation: Water depth

light only penetrates to relatively shallow depths, zooxanthellae are photosynthetic

Conditions for Coral Reef Formation: Water temp

corals only survive in narrow range of water temps. Global warming is resulting in temperature that are too warm for corals to tolerate when too warm corals expel zooxanthellae —> coral bleaching

Conditions for Coral Reef Formation: Salinity

corals need correct amount of salt water around them, areas with freshwater run-off may not be of correct salinity.

Conditions for Coral Reef Formation: Water clarity

water needs to be clear for light to pass through, if there is a lot of sediment or pollution in the water the clarity decreases and zooxanthellae may not receive enough light

Conditions for Coral Reef Formation: Water pH

increased CO2 from fossil fuel emissions is being absorbed into ocean water resulting in a lowered pH that is detrimental to coral growth, acidification results in less calcium carbonate compounds being available in water from corals to use when building reefs

Zooxanthellae

algae that live in corals and provides nutrients - mutualistic relationship with coral

Biomes

large geographical area that contains communities of plants and animals that are adapted to living in that environment

Life in Hot Deserts: Plant Species

Saguaro Cactus: native to Sonoran desert in southwestern United States

Adaptations:

• thick waxy skin (waterproof)

• bristles for defence

• single long taproot to collect water when available

• water stored in sponge like material

Life in Hot Deserts: Animal Species

Fennec Fox: native to desert areas of Sahara North America

Adaptations:

• very large eats, highly vascularised to help remove heat and to help locate small prey animals underground

• nocturnal hunters

• spend day in underground dens (for shade)

• kidneys reabsorb most of water that passes through and rarely urinates

Life in Rainforest: Plant Species

Kapok tree: located in Costa Rica and the Amazon

Adaptations:

• competition for rain water and sunlight is high in rainforests

• grow very tall and create part of canopy layer

• large buttress roots form strong foundation for rapid growth of tall trunk or shallow soil

Life in Rainforest: Animal Species

Harpy Eagle: native to Central and South America

Adaptations:

• binocular vision allows accurate judge of distances and tracking of fast moving prey

• strong and sensitive hearing allow detection of sound of prey moving

• sharp beak allows capture and feeding on large prey

• broad strong wings enable movement through dense forest canopy with ease and glide through air silently

• strong talons to crush skulls of prey

Niche Paritioning

process by which competing species use the environment differently in a way that helps them coexist (may be spatial or temporal)

Competition

occurs when two or more organisms fight for the same limited resource (such as food, space, light, or mates) in an ecosystem.

Intraspecific Competition

within the same specie

Interspecific Competition

between different species

Predation

biological interaction where one organism, the predator, hunts, kills, and eats another organism, the prey. This interaction benefits the predator but is fatal for the prey. Killing + eating prey or eating something that has recently died (scavenging)

Mutualism

2 species providing food or other resources where both benefit

Parasitism

Symbiotic relationship where one organism, the parasite, lives on or in a host organism and derives its nutrients at the host's expense. The parasite benefits, while the host suffers harm, though it is usually not immediately killed.

Obligate Anaerobes

single celled organisms that have no tolerance in the presence of O2, live in places like soil, deep water, animal intestines, use alternative elements for electron acceptor

Facultative Anaerobes

carries out both anaerobic and aerobic respiration, can switch depending on availability of O2

Obligate Aerobes

require oxygen and cannot convert food nutrients into energy without it —> fish

Autotrophs

produce their own food through photosynthesis or chemosynthesis

Heterotrophs

consume food source

Holozoic nutrition

ingesting all or part of an organism, type of Heterotrophic nutrition

Mixotrophic Nutrition

Can make and ingest their own food, type of Heterotrophic nutrition

Faculative Mixotrophs

can survive in 1 system but use other as supplement

Obligate Mixotrophs

need both auto and heterotroph systems to thrive

Saprotrophic Nutrition/Saprotrophs

secrete digestive enzymes and then absorb the products of digestion, capable of breaking down dead organic material, decomposers

chemosynthesis

generating energy from reactions involving chemical compounds (chemoautotrophs)

Incisors

cut into food

Canines

used for ripping and tearing tougher materials

Premolar

crushing or slicing food

Molar

grinding food and reducing it to a paste before swallowing

Adaptations of Predators: Chemical

some predators inject chemicals into their prey while others use chemicals to attract prey to their hunting grounds

Black mamba: injects prey with paralysing neurotoxins

Orb-weaver Spiders: release a chemical that mimics sex pheromones of moths then wait for prey to arrive

Adaptations of Predators: Physical

predators have adapted sensory organs that provide advantages to catching prey

Owls: low light vision for night hunting

Bats + Dolphins: echolocation

Vultures: keen sense of smell

Sharks: organs called ampullae of Lorenzini register electromagnetic fields for finding prey

Adaptations of Predators: Behavioral

Ambush predators: hiding and waiting for prey then attacking, web building spiders, angler fish with illicium

Pack hunting: teamwork to attack prey often larger than predator, wolves must have a leader to create trust, wasps, ants, bees, termites

Pursuit predator: rely on speed to outrun prey, cheetah

Persistence hunting: pursuing prey for several hours until they fatigue, humans living as hunter gatherers

Adaptations of Prey: Chemical

prey may produce chemicals to deter a predator such chemicals taste bad or are toxic, poison dart frogs secrete an alkaloid on their skin that interferes with muscle function, including the heart which can lead to death

Adaptations of Prey: Physical

Camouflage: taking on the appearance of the organism’s surroundings, some octopi can change their colour and skin texture

Aposematism: coloration that warns predators of prey’s danger, poison dart frogs bright colours, non-venomous king snakes look like venomous coral snakes

Adaptations of Prey: Behavioural

fleeing at the sight of a predator

Staying in Large Groups: when attacked by predators elephants form a tight group with smaller elephants in the middle and large elephants on the outer edge

Canopy

most of the crowns (tops) of trees are found. trees position leaves far from ground to gain maximum exposure

Understory

shorter trees

Shrub layer

shortest trees and shrubs

Forest floor

small non-woody plants often has full shade

Harvesting light from: Lianas

• are vines that cannot build trunks large enough to reach the canopy

• use trees to climb and reach canopy

• seedlings are attached to shade and are drawn towards tree for support

• roots in soil

  eg) Kudzu

Harvesting light from: Epiphytes

• use tree for support and access to sun

• roots are not in soil

  eg) orchids

Harvesting light from: Shade-tolerant shrubs

• grow on forest floor

• absorb remaining light after passing through other leaves

• Herbaceous plants (no woody stem) are often shade tolerant

  eg) bananas

population

a group of organisms of the same species living in the same geographical area at the same time and are able to interbred

Systematic Sampling

when a line or grid is set up and measurements or counting are carried out as specific and regular intervals

Random Sampling

Arbitrary chosen areas of the population are selected for sample, removes bias from selecting particular areas

Sampling sessile organisms

• random sampling

• sessile organisms: plants, coral

• quadrant sampling: square of particular dimension maintains consistent surface area for fair comparison

Sampling motile organisms

• CMRR method

• sampling technique allows an estimate of animals in ecosystem

Capture, Mark, Release, Recapture method

1. capture some individuals in a given space

2. mark them

3. release them back into the ecosystem

4. wait a given amount of time

5. capture a second sample

Carrying Capacity = K

maximum number of individuals that a particular habitat can support —> environments can only allow a population to get so large before resources result in established population size

Limiting Factor

Limiting factors are those that prevent a population from getting bigger or reduce a population’s size. density dependent + density independent

Positive feedback systems

Something increasing the population that the system encourages - more of the same

Negative feedback systems

prevents system from going too far in 1 direction leads to carrying capacity

Population growth curves

1. exponential phase: number of individuals increases at a increasingly faster rate

2. transitional phase: growth rate slows down considerably but still increases

3. plateau phase: stationary phase number of individuals stabilises no more growth

Community

a group of populations in an area including plants, animals, fungi and bacteria living and interacting with each other in an area

herbivory

eating plant material

Pathogenicity

ability of microbes such as bacteria and viruses to cause disease in other species

Endemic

a species found only in one location in the world

Invasive

introduced into a new area from a distant origin and their populations grow so well they cause problems for the species already living their

Top-down controls (of Population)

seen when a species can be reduced by other species feeding on it. herbivory for plant populations - the more eaten the smaller the population

Bottom-up controls (of Population)

seen when a species population can be decreased by lack of resources eg) food, sunlight, or minerals

Allelopathy

production of secondary metabolites that influence growth and success of other organisms

primary metabolites

molecules needed for basic functions

secondary metabolites

molecules produced to impede or kill competitors

photoautotrophs

producers that use sunlight as their energy source

chemoautotrophs

producers that use chemosynthesis for their energy source usually found in ecosystems with no light

trophic levels

indicate how many organisms the energy in a system has travelled through — a method of classification of organisms based on its feeding relationship with other organisms

food chains

linear sequence of organisms through which nutrients and energy pass as one organism eats another