Life science - Semester 1

The 4 spheres

The 4 spheres

• Biosphere

• Lithosphere

• Atmosphere

• hydrosphere

Biosphere

is made up of the parts of the earth where life exists all ecosystems.

Lithosphere

Solid outer part of the earth, is made up of the brittle upper portion of the mantel and the crust.

Atmosphere

Is made up of layers of gases surrounding a planet or other celestial body.

hydrosphere

Total water on the planet, includes ice, all water in the air on the ground, and underground.

Biotic factor

living components within an ecosystem that influence other organisms or the environment.

Abiotic

non-living components of an ecosystem that can influence living organisms and environment

Biosphere: Levels of organisation

biosphere → biome → ecosystem → community → population → species

8 major terrestrial biomes

Tropical rain forests, savannahs, subtropical deserts, chaparral, temperate grasslands, temperate forests, boreal forests, and artic tundra.

+ marine biome and freshwater biome

Food webs/food chains

food webs→ demonstrate across whole ecosystems and shows the biodiversity of an environment

food chains → show flow of energy

Photosythsis + equation

Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar.

(Carbon dioxide + water → glucose + oxygen + water)

Hydrothermal vents and thermal environments

create chemical energy in inorganic chemicals, released by the vents. allows organisms to survive in those ecosystem s

Transfer of energy

every transfer Some energy is lost as heat energy that cannot be used as a source of energy for living. Only 10% of the energy transfers to the next trophic levels for next transfer

Trophic levels

• First Trophic Level: Autotrophs. (the producers),

• Second Trophic Level: Primary Consumers.

• Third Trophic Level: Secondary Consumers.

• Fourth Trophic Level: Tertiary Consumers.

• Fifth Trophic Level: Apex Consumers.

Autotrophs, Consumers, Detritivores, and Decomposers

3 types of ecological pyramids + define purpose

are graphical representations of the relationships between different organisms in an ecosystem.

Numbers - how many producers/consumers are within each trophic level?

Biomass - the biomass (dehydrated mass) present shows relationships between biomass and trophic levels

Energy - shows available energy at each trophic level. (only 10% transfers)

Biodiversity

full range of different living things in a particular area or region; it can be described at various levels.

1. range of different species

2. genetic diversity

3. diversity of ecosystems present in larger area

Crucial for health and resilience of ecosystem, provides a variety of species with unique traits, enabling ecosystems to adapt to environmental changes

What high biodiversity enhances

ecosystem stability, making them resistant to disease, invasive species and climate fluctuations

Species richness

number of species within a given area

Species abundance/evenness

number of individuals within each particular species (also known as species eveness)

SDI

Ecosystem stabliity

closely linked with biodiversity not clear what level of biodiversity is required to guard against ecosystem disfunction.

Species loss

past certain point is likely to be detrimental to the functioning of the ecosystem and its ability to resist change.

Keystone species

significant influence on ecological communities which have a pivotal role in ecosystem function and ecosystem stability

Threats to biodiversity

1. habitat loss

2. climate change

3. pollution

4. over exploitation of species

5. invasive species

Species diversity

takes into account both the number of species present and evenness of each species measured by SDI

what is an ecological relationships + examples

Ecological relationships describe the interactions between and among organisms within their environment

symbiotic relationship

Living together with another organism in close association. mutualism, commensalism , paratism

Intraspecific vs interspecific

Interspecific - between different species

Intraspecific - between members of the same species

autotrophs, heterotrophs, and detrivore carnivores, omnivores

Autotrophs/ producers they are able to make their own food from raw materials and energy

Heterotrophs occupy the second and third levels in a food chain, a sequence of organisms that provide energy and nutrients for other organisms.

Detrivore an animal which feeds on dead organic material, especially plant detritus.

Carnivore is an organism that mostly eats meat, or the flesh of animals.
An omnivore is an organism that eats plants and animals.

Herbivore only eat plants

Competition

is the struggle between organisms for the same environmental resources, eg. food, nesting sites and mates.

role of decomposers in an ecosystem and cycling matter

Decomposers, such as bacteria and fungi, play a critical role in ecosystems by breaking down dead organic matter. This process recycles nutrients back into the soil, making them available for plants, which are the primary producers. thus maintaining flow of energy and the cycling of matter, ensuring ecosystem stability and productivity.

Predation + examples

involves one organism eating another

Commensalisim

one organism is benifited and the other is unharmed

eg. barnacles on a whale

Mutualism

Both organisms benefit from the association. eg. nitrogen fixing bacteria on legume nodules

Parasitism

The parasite benefits at the expense of the host eg. heartworms in dog

Amensalism

but in this association among organisms of two different species, one is destroyed or inhibited, and the other remains unaffected

Abiotic factors in Water

Water pH

Light

Temp

Turbidity

Oxygen levels

Abiotic factors in Soil

Soil texture/ moisture

Soil nutrient

Temp

pH Levels

Atmosphere

and levels

Troposphere

stratosphere

mesosphere

ionosphere

Thermosphere

exosphere

“Todays smalls moments. Tomorrows epic”

Trophosphere

the lowest layer of the earth atmosphere, - were most weather occurs

Stratosphere

Very drak layer of atmosphere, very little waters vapour, therefore few clouds

• ozone layer

Mesosphere

coldest layer

Thermosphere

experience extremely high temps due to the apsorption of solar radiation

Exosphere

outer most layer

Earths climate

the atmosphere play a crucial role roel regulating the earth’s climate, influencing temperature, pressure, and weather patterns.

Cliamte change

Climate change refers to long-term shifts in temperatures and weather patterns.

Sporadic evens leading to climate change and why

Volcanic eruption -

cooling - ash and sulfare aerosols

warming - large volumes co2, increase greenhouse warming

Plate tectonics and climate change

-alter ocean currents

-more glaciers over land

-also move plates to create more volcanic activity.

what is Nitrogen cycle

a nutrient that cells need to make proteins, amino acids and DNA important for plant growth and chlorophyll which helps absorbs sunlight

Stages of nitrogen cycle

Fixation -coverts nitrogen in the air to ammonium, which is biologically available

Nitrification - bacteria change ammonium to nitrates to be absorbed by plants

Assimilation: - Plant absorb nitrates by the roots

Ammonification - decomposers change nitrogen into ammonium to re-enter the cycle

denitrification - nitrogen in the soil gets back into the air

link earths spheres and carbon and nitrogen cycle

Earth's spheres are interconnected in the carbon and nitrogen cycles. The atmosphere exchanges CO2 and nitrogen with living organisms. The biosphere involves plants and animals that cycle these elements through photosynthesis, respiration, and decomposition. The lithosphere stores carbon and nitrogen in rocks and soils, releasing them through natural processes and human activities. The hydrosphere absorbs CO2 and cycles nitrogen through marine ecosystems. These interactions sustain life and regulate environmental processes.

Impact of excess nitrogen

due to human activity

-burning fossil fuels

-clearing forestlands and greenland’s

-fertilizer

• not all fertilizer is absorbed by plant some stay

• and get carried into aquatic systems via rain

• nitrogen on waterways lead to over growth in algae

• which blocks sunlight-reaching organisms

What is Carbon cycle + Three types

the biogeochemical cycle by which carbon is exchanged among the spheres

• atmospheric carbon cycle

• terrestrial carbon cycle

• oceanic carbon cycle

Binomial nomenclature

scientific name 2 words

Genus name and Species name

Stages carbon cycle

• Co2 gas moves from the atmosphere to the body through photosynthetic and cellular respiration

• CO2 moves back from to the atmosphere when the organims die and decompose

• carbon enters the geosphere when the remains of the organism are trapped under the sediment layers

• carbon can also enter the atmosphere through bushfires and volcanic activity

Amospherical carbon cycle

• CO2 leavess atmosphere- photosynthies

• CO2 dissolves into bodies of water - forming carbonic acid

• carbonic acid absorbed into rocks

Terrestrial carbon cylcle

• Included organic carbon in all organisms+ in soil

• included in organic carbon

• autotrophs extract CO2 from air covert into organic carbon

• heterotrophs receive carbon

• return to air through respiration

Oceanic carbon cycle

• dissolved CO2 converted to carbonate

• converted by organisms into organic carbon - photosynthesis

• exchanged through food chain

• surface layer dissolved organic carbon - exchanges rapidly with atmosphere

• deep layer holds dissolved inorganic carbon

carbon sequestration

CO2 captured from atmosphere and stored in nature helps mitigate climate change by reducing amount of CO2 available

Charateristics of a living thing

MRS GREN C

Movement

Respiration

Sensitivity

Growth

Reproduction

Excretion

Nutrition

Cells

living organisms can exist only if there is:

• Energy

• liquid water

• the chemical buildings blocks required for life

• stable environmental conditions

Prokaryotes

• Prokaryotes are organisms whose cells lack a nucleus and other organelles.

• have no true nucleus,

• their genetic material is found a region called the nuclear area

• UNIcelluar organisms

• like bacteria

Eukaryotes

• having their genetic material contained within nuclear membrane

• more complex celluar organism and have internal membranes - called organelles

• eg. fungi, protistans, animal and plant cells

Fungal cell vs plant cells

plants are autotrophic (make own energy) and fungi is heterotopic (must take in energy)

• both are eukaryotic

• both have cell walls are stationary and typically multinuclear

Protists

• unicellular organisms

• classified under kingdom of Protista as eukaryotes

• some contain cell wall

• can be autotrophic, heterotrophic, parasitotic or saprotrophic

• exhibits sexual and asexual reproduction

Cell size

Classification

placing living things in groups based on their internal structure and functional characteristics

order the hierarchy

Domain → kingdom → phylum → class → order → family → Genus → species

taxonomy

the science of grouping living things based on like characteristics

Types of kingdoms

Monera, Protista, Fungi, plantae, animalia

rocky shores

species closer to high tide mark are often best at being exposed to air and sunlight without drying out but worst at avoiding predation and worst at spending time under water for long periods of time

these physical and ecological pressures led to distinct zones in the community

Adaptaion + name the 3 types

A biological mechanism by which an organism adjusts to new environments to changes in current eviroment

Structural adaptation, physiological adaptation, behavioural adaptation

Structural adaptation

features on an organism body that helps it survive or reporduce

Physiological adaptation

an internal body processes to maintain homeostasis for an organism to survive in the environment which it exists

Behavioural adaptation

Something an animal does usually i response to some type of external stimulus in order to survive

Phyla’s

Abiotic factors and intertidal zones.+

effect on organisms