B4.1, B4.2,C4.2

Habitat

Place where an organism or group of organisms lives and interacts with their surroundings

Consists of both abiotic and biotic factors

Describing the habitat of a species

Geographical location

Physical location (type of soil, food, other plants and animals)

Ecosystem (biotic and abiotic factors)

Habitats classified into 2 broad categories

Terrestrial- land based

Aquatic- water based

How organisms adapt to abiotic environment of their habitat

Genetic changes that increases organism’s chance of survival and reproduction in a particular environment

Occur though mutations or selective pressures

Abiotic conditions in a habitat; temp, light, moisture

Sand dune habitat and adaptation

Marram grass has

Tolerance to drought; deep root system to access water in drought

Tolerance to salt; ideal to grow in sand

Strong roots to anchor firmly in sand against wind and waves

trap sand particles in roots and stems to stabilise and prevent erosion

Mangrove swamp habitat

Develop when salt water and freshwater is there

When the water fluctuates with the rides

High levels of salinity (salt)

Rhizophora apiculata adaptations

Halophyte- can survive in high levels of salt in the soil

Pneumatophores help provide roots with oxygen even when soil is water logged

Can survive in flooded areas, development of still roots that support the tree above water

Abiotic variables affecting species distributions

Influenced by range of tolerance for abiotic factors

Temperature, humidity, light, water availability

Can also influence interactions between different species in an ecosystem

Species distribution

Geographic location and range of occurence of a species

Abiotic factors affecting plant growth and adaptations

Insufficient light- ferns grow larger thinner leaves for more light absorption

Too much light- cacti have thick waxy skin to retain water and reflect sunlight

Inadequate water supply- Rice plants can reduce water loss by closing stomata

Abiotic factors affecting growth of animals

Temperature too low- penguins thick layer of blubber to insulate from cold

Food supply- Herbivores adapted teeth to extract nutrients from tough plants

Climate patterns- Ground squirrels hibernate in winter to conserve energy and survive in colder temperatures

Range of tolerance as limiting factor

Range of environmental conditions within an organism can survive and function optimally (abiotic factors)

If the environmental cinditions in an area are within their tolerance the species is more likely to occur there

Adaptations of a species give it a range of tolerance

Use of transect lines for sampling

Study correlation between abiotic variables and species distribution

Distribution and abundance of plants in a certain area

Establish a straight line across a habitat and take measurements or samples at regular intervals along the line

Measurements can be plant species richness, plant height, leaf area index, soil moisture, animal abundance

Use sensors to measure physical or chemical properties like temp, pressure, humidity and dataloggers that record data from sensors over time

Coral reef formation , which abiotic factors its influenced by

Marine ecosystem- complex and dynamic

Strongly influenced by abiotic factors (water depth, pH, temp, slainity) which have an effect on survival and growth of marine organisms

Sensitive to abiotic conditions,

Water depth- grow in shallow waters for sunlight to penetrate for algae to grow

pH- thrive in slightly alkaline 8-8.4

Salinity- very salty water

Water clarity- must be clear so sunlight can penetrate for photosynthetic algae to provide coral with food

Temperature- 23-29 degrees

Biome

Large community of plants and animals that occupy a distinct geographical region and are adapted to its climate and other environmental conditions

2 main abiotic factors to determine biome that will exist in a particular region

temperature and rainfall patterns

Interact with each other to make a climate affecting the organisms that can survive in that environment

Temperature affects rate of biological processes

Rainfall affects availability of water

Terresterial biome distribution graph

Areas with high temp and high rainfall are tropical rainforests

Areas with low temp and low rainfall support tundra biomes

for any given temp and rainfall patterns, a biome will be supported

Biomes are groups of ecosystems with similair abiotic conditions which results in

Results in similar communities of plants and animals due to convergent evolution (process where different species evolve to have similar traits in response to environmental pressures)

Biome vs ecosystem

biome is more large and broad and influenced by climatic conditions

Ecosytem is smaller and more specific and can exist in a variety of climates

Adaptations to life in hot deserts

Arid regions, little rainfall, hot in day, cold at night

Octilo

Red flowers to attract pollinators for reproduction

Long stems expand to store water during droughts

Green bark, contains chlorphyll, allows it to carry out photosynthesis even with no leaves present

deep root system to access water deep in soil with horizontal root system

Adapatations to life in hot deserts

Slow metabolic rate allowing it to go for long periods with no food or water

skin covered in bumpy scales to help retain moisture

store fat in tail to survive long time with no food

Gila monster

Adaptations to life in tropical rainforests,

high rainfall and warm temperatures

giant amazon water lily

root system to anchor itself to the muddy bottom of the river and extract nutrients from soil

flowers open at night and emit strong fragrance to attract pollinators

leaves covered in waxy coating to repel water and stay afloat

harpy eagle adaptation to tropical rainforest

Binocular vision to judge distances and track fast prey

sharp beak to capture and feed on large prey

strong and sensitive hearing to detect sounds of prey

sharp claws to crush skulls of prey

Ecological niche

the role of a species in an ecosystem, where an organism lives, what it does, its role and impact on the ecosystem

The distribution of species

determined by interactions from the environment’s biotic and abiotic factors

biotic factors- competition for resources, disease, predators, parasites

abiotic factors- temperature, wind, precipitation, sunlight, pH of water, soil

Work together in balance to create an ecosystem where only certain organisms can survive

Not only can the environment impact that distribution of species

But species can have an impact on the environment

Modes of repsiration

obligate anaerobes- Organisms that can only survive in environments lacking oxygen

Facultative anaerobes- Organisms that can survive in environments that contain or lack oxygen

Obligate aerobe- organisms that can only survive in environments that contain oxygen

Autotrophic vs heterotrophic

Autotrophic uses energy from the sun to generate their nutrition (plant, algae some prokaryotes), use photosynthesis making carbon adioxide and water into glucose and oxygen

Heterotrophic organisms need to take their nutrition from external sources (most animals)

Photosynthetic prokaryotes have

infoldings of their plasma membranes where photosynthesis takes place

Holozoic nutrition

Organisms that take in solid or liquid food internally

mostly animals (also protozoa and amoebas)

After food is brought in it is digested and broken down into building blocks, used to build new materials for growth and development

Mixotrophic nutrition

Use a combination of methods of generating their nutrition, neither fully autotrophic or heterotrophic

favours marine environments making up almost all marine plankton

Can take in CO2 like a plant but also nutrition like an animal

they release CO2 when respiring

Euglena is a freshwater protist that is autotrophic and heterotrophic, unicellular, eukaryote, can take in bacterial cells by endocytosis and digest them by digestive enzymes stored in lysosomes, but also have a light sensitive spot and position themselves to have maximum light reach their chloroplasts

Obligate mixotrophs

must utilise both heterotrophic and autotrophic means to grow

Facultative mixotrophs

Can survive using one method of nutrition (heterotrophic or autotrophic) which is supplemented by the other

Saprotrophic nutrition

Method by which the organism secretes digestive enzymes to break down dead organic material, like cellulose (tough part of dead plants) into simpler molecules which the organism absorbs

Fungi and bacteria using this heterotrophic nutrition can be called decomposers

Nutrition in archaea

3 domains of life- Archaea, eukarya, bacteria

The method in which they derive their energy is very diverse and they can use a wide variety of sources (metabolically diverse)

Some use oxidation of inorganic chemicals for their metabolism or oxidation of carbon compounds to provide energy for ATP production

Dentition

Humans are found in hominidae family

teeth are highly mineralised so they are well preserved

examinations of skulls and teeth of our ancestors allows us to make deductions about their diet

Early ancestors ate

fibrous plant material, needed to consume a large volume to get enough energy

Once higher energy meat could be eaten, the digestive system could be reduced, as well as teeth count and jaw size as they needed to do less chewing on plant

Paranthropus Robustus

Existed a long time ago in South Africa, had large teeth with thick enamel and chewed at the back of their jaw, large chewing muscles and large face, herbivores, eat tough grass and sedges

Homofloriensis

Had small skull size but large teeth, omnivores their diet was plant and uncooked meat, markings on their teeth show wear shows they had a tough fibrous diet requiring a lot of chewing

Homo sapiens

Gathered food and hunted, jaws less heavily developed with smaller teeth (omnivores)

Adaptations of herbivores, insects, aware of predators, teeth

Insects evolved a strong pair mandibles on each side of their head used to cut, tear, crush and chew their food

In herbivores their front incisors are long and flat and work like scissors to cut plant material, back molars large, flat, where plant material gets chewed sideways to increase SA for enzymes to break it down

Need to be aware of predators, so they have eyes far apart on either side of their head to increase visual field to respond quickly to danger

Adaptations of plants

Some plants make toxic secondary compounds not involved with growth and life of the compound but can be toxic to those who eat it used to prevent herbivory, some animals developed repsonse to this by having enzymes that enable them to metabolise these compounds

some plants evolved non toxic chemicals only becoming toxic after ingestion by animal called phytochemicals

plants can make themselves unpalatable to avoid consumption by having thick rigid leaves that are difficult to chew, some have spiky thorns which are sharp extensions of epidermis to prevent herbivores from eating

or have microscopic thorns to avoid insets

Adaptations of predators physical

Carnivores use speed agility, sharp clas and teeth to hunt and capture prey

Have digestive systems capable of breaking down prey

finely tuned sensory systems (eagles spot prey, owls hear prey, mole can smell prey)

Adaptations of predators chemical

Some predators release certain chemicals that poison or paralyse victims (salts and protein toxins) like venom

Brazilian fire ant bites into its prey with mandibles and its stinger inejcts venom causing a painful sting

Cone snail injects venom into its prey via harpoon including insulin to cause sugar levels to drop and shut the fish down

Behavourial

Dolphins work together in a circular motion by beating their tail fin they createe a ring of mud to catch their prey

Margay is a good mimic and makes calls that sounds like a distress call to the monkey prey as the parent comes to save the offspring, margay catches the prey

Adaptations of prey physical

camoflauge to blend into background using their coats, zebra stripes into grasses

some have bright colors to indicate toxicity to deter predators, poison dart frogs

Quick and agile to escape predators

Adaptations of prey chemical

Chemicals released by prey into surroundings noxious odours or toxins to harm predator (skunk releases odor when frightened)

Adaptations of prey behavourial

prey can work together to look like one larger organism, mackarel use this strategy, school of fish

Adaptations of plants to harvest light

Need light for photosynthesis

climbing plants (lianas) can climb up tall trees to harvest as much light as possible

Epiphyte plants grow entirely on the branches of another plant using the moisture from plant as source of water, strangler fig starts as sticky seeds high up on a tree and grow roots down to encompess the trunk of their host, can eventually kill host (strangler epiphytes)

Trees that reach canopy layer, ex. banana tree, stems reach out to the canopy layer as that is where most sunlight can be absorbed

in the shrub layer the plants are shade tolerant, and have large broad thin leaves to have maximum SA and sunlight

On forest floor herb layer plants have soft stems to tolerate low light conditions

Fundamental niche

The niche of an ecosystem in which an organism can live and reproduce (takes into account environmental and social limitations for organism)

Realised niche

Where the organism is best adapted and is able to live and reproduce, much smaller due to other constraints like presence of other species

Realised niche formed when

species within a fundamental niche have to deal with pressure of coexisting with the other species in the environment, species forced to live in a smaller niche

Competitive exclusion principle

If two species with identical niches compete, one will drive the other to extinction, resulting in elimination of one of the competing species or restriction of both to a part of their fundamental niche

Within an ecosystem

organisms transfer energy and matter among themselves

Matter

Anything that occupies space and has mass (nutrients, gases, substances for functioning of living organisms)

Energy

The ability to perform work or cause change (biological processes like growth, movement, reproduction)

Open system

Both energy and matter can be exchanged with the surroundings (ecosystems like tropical rainforests, continous input and output of energy and matter)

Closed system

Allow for exchange of energy with the surrounding environment but restricts the flow of matter, rare in nature, only in controlled experimental environments

Isolated systems

Neither energy nor matter are exchanged with surroundings, do not naturally occur, ex. universe itself

flow of chemical energy through food chains

Chemical energy passes to a consumer as it feeds on an organism that is the previous stage in a food chain

Primary source of energy sustaining most ecosystems

Sunlight, through photosynthetic organisms, sunlight energy is converted to chemical energy, and used by other organisms to survive

plants are producers

organic energy rich compounds produced by plants are transferred through food chain

within environments with limited light like deep ocean or caves, chemosynthetic organisms extract energy from inorganic compounds like minerals and sulfur

Bacteria convert inorganic molecules to organic compounds in chemosynthesis, foundation of food web in this environment

food chains and food webs represent feeding relationships

in a community, arrows indicate the direction of energy transfer and biomass

Decomposers

Break down dead organisms, and organic matter (dead parts of an organims, faeces, dead whole organism)

Bacteria, fungi, invertebrates extract energy and nutrients from decaying matter

secrete enzymes which break down complex carbon compounds into simpler organic molecules

they obtain energy while releasing nutrients back into environment

Autotrophs

Primary producers capable of syntehiszing carbon compound from inorganic ones using external energy source

Serves as a source of energy and nutrients for other organisms in the community

anabolic chemical reactions like carbon fixation and processes to build macromolecules require energy input from sunlight

photoautotrophs

use light as an external source of energy to synthesize carbon compounds from inorganic molecules , plants algae, bacteria (some)

most derive energy through photosynthesis, convert sunlight water into glucose and other compounds

chemoautotrophs

obtain energy through oxidation of inorganic compounds like iron, sulfur, magnesium, releases energy utilised for carbon fixation and synthesis of macromolecules

Iron oxidising bacteria found in iron rich environments, by oxidising iron they convert released energy into a usable form for synthesizing organic compounds

Heterotrophs

Cannot produce their own organic molecules and rely on consuming other organisms or organic matter to obtain energy and nutrients

Consumers, herbivores, carnivores, omnivores, decomposers

Break down complex organic compounds from autotrophs or other heterotrophs using internal or external digestion to break down proteins and nucleic acids

Then use the nutrients obtained as building blocks to construct carbon compounds used to support metabolic activites and provide energy for biological function

Release of energy by cell respiration

Done by autotrophs and heterotrophs

Oxidation of carbon compounds in cell respiration, organisms extract energy from organic molecules and convert it into a useful form, ATP, some lost to heat

Producers

Use an external energy source and convert inorganic molecules into carbon compounds

base of food chain

provide nutrients for all following trophic levels

plants, algae

Primary consumers

Herbivores or omnivores

Consuming producers directly to obtain energy

Birds, some insects

Transfer energy from producers to higher level consumers

Secondary consumers

Feed on primary consumers as main energy source

Larger mammals, some reptiles

Tertiary consumers

Feed on other organisms, top level predators, eat primary and secondary consumers

Lions, killer whales

Some species can occupy

can occupy more than one trophic level in different food chains

omnivores can be both primary or secondary consumers, dietary flexibility, adapt based on food availability

Biomass

Total dry mass of a group of organisms in a specific area or volume, units of mass/unit area

Biomass includes energy

Tissues of organisms composed of organic compounds which contain energy

organisms have to be dehydrated

Measuring biomass in a food chain over time allows

the estimation of energy availability at each trophic level (test efficiency of energy transfers)

use energy pyramid, each trophic level is a bar which represents amount of energy units per area per time

Most energy is not efficiently transferred from one trophic level to the next

Law of conservation of energy

Cannot be created or destroyed but only converted from one form to another

Only 10% energy transferred stored in biomass from one trophic level to the next

Energy losses between trophic levels can occur due to

incomplete consumption- Organisms sometimes don’t consume all parts of the organisms they feed on, uneaten biomass

Inefficient digestion- Unable to absorb all the energy contained in the consumed food during digestion, biomass released as faeces waste

Inefficient energy conversion- Not all energy obtained is efficiently converted and stored in the organism’s tissues

Used in metabolic processes- Use energy for respiration, movement, growth

Heat dissipation- Energy dissipates as heat as a consequence of cellular respiration and other metabolic reactions

Decomposers and detritus feeders

not included in food chains, play a role in energy transformations in ecosystems

obtain energy from breakdown of complex organic matter derived from dead organisms

Release simple inorganic compounds back into environment making available for other organisms like producers

Heat loss

Energy transformed from one form to another, never 100 % efficient

-In cell respiration, organisms use chemical energy stored in chemical compounds and convert it to ATP

Not all energy fully captured or converted to ATP

some energy lost as heat when ATP is produced in cell respiration and when it is used in cells

dissapates into surroundings

Length of food chains, why restriced number of trophic levels

Energy loss between trophic levels cause a great decrease in amount of energy stored as biomass at each trophic level

As energy moves up the trophic levels, amount of energy available becomes insuffiecient to sustain another trophic level, restricting the number of trophic levels

At each stage in the food chain, less or smaller organisms

As total biomass decreases

Energy content per unit mass stays the same, because energy content total decreases because of a decrease in biomass, but per unit area its the same

Primary production

Rate at which producers accumulate carbon compound in their biomass, biomass grows as organisms grow/reproduce

measured in units mass/area/time

Higher producer biomass supports greater number and diversity of consumers in an ecosystem

rate at which primary producers accumulate biomass varies by region and season (biome), more sunlight, more photosynthesis, more primary production

Secondary production, why its lost, and why its lower than primary

Secondary production refers to rate at which consumers accumulate carbon compounds as part of their own biomass

Get carbon compounds by ingesting other organisms

carbon then lost as its converted to CO2+H2O in cell respiration

Always lower than primary because loss of biomass and energy in each trophic level

Carbon cycle

Allows carbon atoms to be exchanged between earths systems

Carbon stored in reservoirs known as carbon sinks

Any environment that absorbs more CO2 from atmosphere than it releases

Forests, ocean, soil

Carbon sources

Locations or processes that release more carbon into the atmosphere than they absorb

Increasing levels of CO2 (greenhouse gas) increasing climate

burning fossil fuels to obtain energy, releasing CO2 stored in earth’s crust, cellular respiration

Fluxes

Carbon atoms moving between atmosphere, lithosphere, hydrosphere, biosphere

Carbon in plants moves to

animals that eat them or the animal that eats that animal

Ecosystems can be carbon sinks or sources

dependent on the balance between photosynthesis and cellular respiration

photosynthesis captures CO2 from atmosphere and incorporates into carbon compounds

Cell respiration releases CO2 back into atmosphere, they break down organic compounds to obtain energy

If photosynthesis rate is higher than respiration rate, uptake of CO2 then it is a carbon sink

If cell respiration rate is higher and there is a net release of CO2 then ecosystem is a carbon source like decaying organic matter

Human impact on CO2 cycle

The combustion of carbon rich reservoirs such as biomass, peat, coal, oil, natural gas releases CO2 emmisions into atmosphere resulting in modifications to the carbon cycle

Producers absorb CO2 to regulate levels in atmosphere but combustion of fossil fuels releases CO2 stored for millions years, enhancing greenhouse effect (traps more heat), alters equilbirum of sources and sinks, now more CO2 released than absorbed

Carbon sinks vary in dates of formation

Natural combustion

Combustion following lightning strikes is a natural phenomenon contributing to release of CO2

Ignites wildfire, leading to burning of vegetation and organic matter, releasing the CO2 stored in them

Human activities like burning of fossil fuels and combustion of biomass have a greater influence on modifications of carbon cycle, influencing climate change and global warming

Keeling curve

shows concentration of CO2 in atmosphere over time

Annual fluctuations reflect seasonal patterns of respiration and photosynthesis, during growing season, plants undergo photosynthesis recuding CO2 conc, dip in curve, during dormant season, photosynthesis is lower, respiration continues, CO2 levels increase, upwards trend in curve

Consistent increase in CO2 level over years, impact of human activity like combustion fossil fuels

Link between photosynthesis and respiration

Aerobic respiration requires O2 provided by photosynthesis and it produces CO2 released into atmosphere essential for photosynthesis to occur

Reciprocal relationship forms essential interaction between autotroph and heterotroph

The fluxes of O2 and CO2 per year are huge, major interaction between autotroph and heterotroph

Other cycles of matter

All chemical elements required by living organisms are recycled in ecosystems

ensures the continual availability of essential elements for maintaining life

Decomposers recycle matter by breaking down organic compounds and returning nutrients back into environment

Community

a group of populations living and interacting in a given habitat, only biotic factors

Ecosystem

A group of populations living and interacting in a shared habitat, abiotic and biotic factors

Population

A group of organisms of the same species living and interacting in a given area which can interbreed

Decomposers excrete

inorganic nutrients