Ecology - Grade 9 Biology

Intro to Ecology

Terms: 

• An ecosystem- is a geographic area where plants, animals and other organisms, weather and landscapes work together to form a bubble of life. 

• Biotic factors: include plants, animals and other organisms. 

• Tide pools- contain seaweed, a kind of algae that uses photosynthesis to create food.

  • Also, depending on the changing level of the ocean water

• Biomes- are a large section of land, sea or atmosphere

  • Forests, ponds, reefs, tundra

• Canopies- ecosystems at the top of the rainforest

  • Tall, thin trees such as fig grow in search of sunlight 

• Epiphytes- other plants in the canopy ecosystem

• Understory- ecosystem under the canopy ecosystem

• Delicate coral reef- an ecosystem in the south pacific at risk due to rising ocean temps. And decrease sanity 

Interdependence 

• Organisms and their environment are interdependent 

• Every organism relies on other organisms to survive 

• Everything depends on something else 

Levels of organization

• Study of ecology ranges from the study of an individual organism to the study of the entire plant as the following 

  • Individual

  • Population

  • Community

  • Ecosystem

  • Biome

  • Biosphere

Species

• A group of individuals similar to one another that can breed and create fertile offspring

Population

• Organisms of one species that interbreed and live together within a defined area 

  • Examples

  • Herd of sheep

  • Flock of geese 

  • Colony of ants

  • Culture of bacteria 

  • Sleuth of Bears 

  • Brood of chickens 

  • Pack of dogs

Communities

• Groups of populations comprised many species that live together in a defined area

Ecosystem 

• Combination of the communities and the physical (nonliving) environment 

• Is all living and nonliving factors in a particular place 

• Can be large and small

  • Rotting log

  • Koi pond

  • Lake

  • Clump of dirt

  • Field

  • Old maple tree

  • Bog marsh

Biome 

• A large area that has a particular climate 

• Particular species of plants and animals that live there 

  • Tundra 

  • Rainforest

  • Desert

• A large group of many ecosystems 

Biodiversity 

• Variety of organisms 

• Organisms genetic differences 

• Ecosystems in which they occur 

• Ecological diversity 

  • Different ecosystems in a region 

• Species diversity 

  • Different species within certain ecosystems 

• Tropical rainforests have the highest biodiversity of all biomes 

Factors that affect ecosystems 

• Abiotic

  • Nonliving factors 

  • Soil

  • Pollutants

  • Natural disasters

  • Climate

• Biotic factors

  • Living factors 

    • plants and animals

• Biotic and abiotic both determine the survival of growth of individual organisms and ultimately the ecosystems 

Habitat 

• Where particular populations live 

• Include biotic and abiotic factors 

How do ecosystems form? 

• Constantly changing 

• Succession 

  • Progression of species of replacement over time 

  • Ecosystems evolving 

  • Typically slow 

  • Natural disasters or human disturbances can make sudden changes 

Primary succession 

• Occurs when no soil previously existed is called this 

• The first species to populate the are called pioneer species 

Secondary succession 

• Occurs in areas where soil exits 

• But has been damaged or disturbed 

• Forest fire - example 

Nutrient cycles 

Biogeochemical cycles 

• The matter is neither created nor destroyed

• Can be transformed and passed on

• How carbon, nitrogen and phosphorus pass from the physical environment to living organisms 

About them 

• Bio-life  

• Geo-earth 

• Chemical-elements and molecules 

• 3 biogeochemical essential cycles 

  • Water cycle

  • Carbon cycle

  • Nitrogen cycle 

• Materials to recycle they have to changes/transform states 

• Death and decay contribute to the cycles

• Animals and plants die

  • Bacteria other decomposers break them down in raw elements 

  • Can be absorbed by plants and passed on to animals 

Water cycle 

• All living things need water to survive

• Moves between 

  • Ocean 

  • Atmosphere

  • Land

• By cycling from water vapour to liquid water

Evaporation 

• Liquid water returns to the atmosphere (vaporizers)

Transpiration 

• Evaporation of water from plants 

• Both occur during the daytime when the sun heats up the atmosphere

    Condensation 

• Atmosphere cools

• Water vapour in the air condenses to form clouds 

    Precipitation 

• Water droplets that form clouds 

• Become large enough 

• Droplets fall to the earth 

• Informs of 

  • Rain 

  • Sleet

  • Snow

    Percolation 

• When water returns to earth some is absorbed by plants through their roots 

• Other seeps into the soil to become groundwater

    Runoff

• Surface water found on land 

• That eventually carries back to a lake or ocean 

Water cycle diagram 

Carbon cycle 

Carbon 

• Is an essential element for all living things 

• Is found in 

  • Living tissues 

  • Rocks

  • Atmosphere

  • Ocean

• Less than 1 % is found on earth is in the carbon cycle 

Carbon dioxide 

• Which is in the air is or dissolved in water is used by photosynthesizing 

  • Plants 

  • Algae 

  • Bacteria 

•  As raw materials to build organic molecules such as glucose 

Ways (3) carbon can return to air or water 

Respiration 

• All living organisms undergo cellular respiration

• Use oxygen to break down food 

• CO2 is a byproduct of the reaction (exhaled)

Erosion 

• Marine organisms use it to make sheets 

  • calcium carbonate

• When they die the calcium carbonate breaks down 

• CO forms and returns to the atmosphere 

Combustion 

• When carbon returns to the atmosphere through combustion or burning fossil fuels

• Carbon is locked beneath the earth 

• Dead organisms sediment may gradually transform by heat

• And pressure into fossil fuels 

• This process of fossil fuels releases CO2 

  • Creates greenhouse gases

Nitrogen cycle 

• Makes up 78% of the atmosphere 

• Most organisms are unable to use it in this form

• Bacteria in the soil is very important 

  • Can use atmospheric nitrogen

  • Fix into compounds usable by other living things 

  • Organisms need nitrogen to build proteins and nucleic acids

Nitrogen fixation 

• Bacteria combine nitrogen from the atmosphere with hydrogen 

  • To make ammonia (NH3) in the soil 

Ammonification 

• Production of ammonia by bacteria during the decay of organic matter

Nitrification 

• Production of nitrates and nitrites from ammonia (NO3)

• Bacteria are responsible for nitrification 

• Plants can use nitrites and nitrates to make proteins 

Assimilation 

• Absorption of nitrogen into organic compounds by plants 

  • Absorbed through roots 

Denitrification 

• Conversion of nitrate to nitrogen gas 

  • Which is released back into the atmosphere

Phosphorus cycle 

• Is necessary to build DNA molecules 

  • Also RNA

• Not very common in the biosphere and does not enter the atmosphere 

• Locked into the land or water 

• Is found in rocks and minerals in the soil 

• Rock gradually wear down phosphorus is released into soil or water 

• When organisms die 

  • Decomposers in the soil or water break them down into raw elements 

  • Including phosphorus which can then be reused 

  • When plants absorb phosphate from soil 

    • Can be passed along from plants/producers to other trophic levels

Nutrient limitation 

• The amount that is available directly affects the primary productivity of an ecosystem

• Primary productivity 

  • The rate at which producers produce energy 

Limited nutrient 

• Sometimes ecosystems are limited by a single nutrient that is very scarce or cycles slowly 

Fertilizers 

• Are so popular 

• They contain 3 important nutrients 

  • Nitrogen 

  • Phosphorus 

  • Potassium 

• By using this farmers can ensure that there are enough nutrients

• Their corps grow to their fullest potential

Earth’s sphere 

• Any time matter can occupy one of the four spheres that make up the earth

  • Lithosphere - solid earth 

  • Atmosphere - gases (the air)

  • Hydrosphere - all water 

  • Biosphere - all life 

Biosphere 

• The lithosphere, hydrosphere, atmosphere are abiotic spheres 

• Are found on other planets including earth 

• Earth has fourth called the biosphere

• No other planet in the solar system is known to have this 

• The biosphere is the living surface of the earth 

• Is not separate from abiotic spheres 

• Many life forms are found 

• Underground

• Water 

• Atmosphere 

Energy transfer in the biosphere

• All living things in here need 

  • Space 

  • Water 

  • Nutrients 

• To survive 

• Nutrients are stored as energy 

• Energy is continuously cycled by mean of the food chain 

• A food chain shows how each living thing gets food 

• How energy is transferred from one organism to another 

A diagram to show what it looks like

Food chains vs food webs

• A food chain is a linear flow of energy through an ecosystem

• A food web shows multiple food chains interconnected in an ecosystem 

• Multiple energy paths 

• Food chains and food webs represent the transfer of energy in a community 

Trophic levels 

• In ecology, this level is a position that an organism occupies in a food chain 

• Energy moves through food webs from one trophic level to the next 

First Trophic Level:  Producers 

• organisms that make their own food through photosynthesis (plant, algae, cyanobacteria)

Second Trophic Level: Primary Consumers

• animals cannot make their own food → they eat producers

• called herbivores (plant-eaters)

Third Trophic Level: Secondary Consumers 

• animals that eat primary consumers

• called carnivores (meat-eaters) and omnivores (eat both animals and plants)

Fourth Trophic Level: Tertiary Consumers 

• animals at the top level of the food chain

• called top carnivores but can be omnivores as well

The end of the food chain 

Decomposers

• Organisms that break down dead plants and animals

• Puts nutrients back into the soil → energy for producers

• Examples:  bacteria, fungi (mushrooms)

Detritivores

• a type of decomposer

• decomposers like bacteria and fungi don't eat their food, they break it down.

• detritivores eat large amounts of decaying material and excrete nutrients.

• Examples: millipedes, dung beetles, earthworms, slugs, snails

Grassland food web

Toxins in food chains 

• Each time an organism eats another organism, it gains that organism's energy and nutrients.  Unfortunately, it also gains any toxins that might be stored in that organism's cells.

Bioaccumulation 

• the increase in the concentration of a toxin, such as a pesticide, in an individual organism.

Biomagnification- the increase in the concentration of a toxin in a food chain. 

• toxins accumulate in living things at the top of the food chain when they eat infected organisms lower in the food chain.

Ecological pyramids 

The sun and ecosystems 

• The fuel for an ecosystem is energy from the sun.

• Light energy is used by green plants in the process of photosynthesis to make chemical energy.

• Chemical energy is passed up the trophic levels in a food chain. 

Energy transfer in food chains 

• The greatest amount of energy is found at the 1st trophic level. They are the first organisms to use the energy of the sun.

• As one organism eats another, some energy is used for survival and some energy is lost as heat to the environment.

• Energy Flows In as Sunlight and Out as Heat

Ecological pyramids 

• An ecological pyramid helps us visualize the transfer of energy between the trophic levels in a food chain.

• There are 3 major types of ecological pyramids:

Pyramids of numbers 

• A pyramid of numbers shows the relative number of organisms at each stage of a food chain

Pyramids of numbers 

• A pyramid of numbers can have various shapes. The width of each block should represent the number of organisms.

Pyramid of biomass 

• A pyramid of biomass shows the total mass of organisms at each stage of a food chain.

Pyramid of energy 

• This pyramid compares the amount of energy trapped at each stage of the food chain.

Pyramid of energy - 10%

• As one organism eats another, 10% of energy passes from one trophic level to the next up the food chain. 

• Since there is less energy moving up the food chain, the population size of organisms at higher trophic levels decreases.

Interactions in ecosystems

• Biotic factors in an ecosystem include all living things 

• And the interactions among those living things 

• Interactions define the ecological niche of species 

  • What it feeds on 

  • What it eats 

  • How it behaves 

• Examples of interactions among living things 

  • Symbiosis 

  • Predation

  • Competition 

Interactions - symbiosis 

• Is the interaction between two different organisms living in a close physical relationship

• Example - sea anemones and hermit crabs 

  • Sea anemones hitchhike on the back of hermit crabs

  • Scoring a ride across the seabed and extending their tentacles to est the crab’s leftovers 

  • In return, the anemones fend off hungry octopuses 

  • The other predators use their barbed tentacles 

Types of symbiosis 

Mutualism

• A relationship where both species benefit from the interaction

• Example - sea anemones and hermit crabs, 

• Insects and flowers (pollination)

Parasitism 

• A relationship where one species benefits(the parasite)

• The other is harmed (the host) by the interaction 

• For example - mosquitos (the parasite) sucks the blood of humans (the host)

Commensalism 

• A relationship where one species benefits

• The other is unaffected (no benefit or harm) by the interaction

• Example- egrets (benefits) and the cattle (unaffected)

• Remora (benefits) and sharks (unaffected) 

Interactions 

Predation 

• Occurs when one organism consumes another organism for food 

• The organism eaten is called prey

• Organism consuming prey is called predator 

Carnivorous plants - venus fly trap 

• Affects insects with its flowerlike reddish colour and ripe fruity smell 

• Insects seek the nectar 

  • It will inevitably touch the highly sensitive hairs on the leaves causing the trap to snap shut at lightning speed 

Competition 

• Occurs when two or more organisms complete for the same resource such as 

  • Food 

  • Water

  • Mates

  • Shelter

• Example - sarcastic fringehead 

  • Lives in a small area on the ocean floor where resources for food and space are scarce

  • When an intruder invades that space, 

  • the fringehead attacks fearlessly and aggressively

Photosynthesis and cellular respiration

Energy flow in ecosystems

• 2 processes that drive energy flow in ecosystems

  • Photosynthesis

    • Converts light energy into chemical energy and stores it as food

  • Cellular respiration 

    • Release stored chemical energy as food

    • The reverse process of photosynthesis

Photosynthesis 

• Occurs in green plants

  • Algae 

  • Some bacteria 

• Green plants have an organelle called a chloroplast

  • It contains chlorophyll which traps light energy from the sun 

• Carbon dioxide enters in through small openings called stomata 

• Carbon dioxide, water and light react to make a sugar called glucose 

• Some glucose is used to feed that plant and some are stored for later use 

• During chemical reaction, oxygen is released into the air through stomata 

Photosynthesis equations 

Cellular respiration 

• Occurs in all organisms 

• Cells break down stored energy (glucose) and release useable forms of energy for body movement 

  • Body heat 

  • Reproduction 

  • Etc. 

• Chemical reactions occur in the mitochondria of cells 

• Stored sugar is converted into carbon dioxide 

  • Water 

  • Chemical energy (ATP)

  • Carbon dioxide is put back into the atmosphere to be used again 

Photosynthesis vs Respiration

• Products (ending materials) of one process are the reactants (starting materials) of the other 

Population Limits 

Population and habitats 

Population 

• All individuals of one species that are in a specific area at a certain time

Habitat 

• In an environment in which a population lives and gets its need met 

  • Food

  • Shelter

  • Reproduction

  • Etc.

What influences population size?

Abiotic factors 

• Influence where species can live

• Are determined by 

  • Temp.

  • Soil

  • Light

  • Salinity 

  • Etc

Biotic factors 

• Influence a species success 

• Are determined by competition for resources

  • Food

  • Water

  • Mates

Intraspecific 

• With members of their own species 

Interspecific 

• Also with other species 

Competition in populations 

• Is the demand for resources 

  • Food 

  • Mates 

  • Water 

  • Etc

Intraspecific is competition for mates in different species 

Interspecific is competition for food in the same species 

Limiting factors 

• Population can’t keep growing forever

• Once the population is too big for its environment 

  • The limiting factors regulate its size 

Examples 

• Food and water supply 

• Mates

• Predation/competition 

• Disease 

• Sunlight

• Space (to live and hide)

• Temperature 

• Natural disasters 

Population density 

• Is to measure the number of organisms that make p populations in a defined area 

Density-dependent factors 

• Population becomes too large for its environment 

  • High density 

• Certain factors will reduce the numbers to bring it back to carrying capacity

• Examples- predation,  competition, disease, etc

Density-independent factors 

• Factors that limit population size regardless of the density 

• Affects all populations in a similar way 

• Examples- the destruction of habitat, forest fires, droughts, etc

Top downregulation 

Top-down limiting factors 

• Interactions between top predators and their prey influence population sizes at lower trophic levels 

Increase in top predators

• Population decreases in lower levels

Decrease in top predators

• The population varies in lower levels 

Bottom-up regulations 

Bottom-up limiting factors 

• Limits the availability of resources to lower trophic levels (producers)

• Lack of resources at the bottom of the food chain decreases population in all the higher trophic levels 

Population growth 

Exponential growth 

• No limiting factors 

• J shaped graph

Logistic growth

• Limiting factors are in place 

• S-shaped graph 

Carrying capacity 

• Limiting factors determine the carrying capacity for a population 

Definition 

• The maximum number of organisms an environment can support

Exponential 

• When resources are readily available population grow rapidly 

• Once resources become limited 

• The growth rate slows down and reaches a maximum populations size for the environment 

Northern fur seal

• In the 1800s, the fur trade led to a drastic reduction in the northern fur seal population.  

• This decline prompted the first international treaty to conserve wildlife

• The fur seal population underwent exponential growth following protection

  • but eventually levelled out at the ecosystem’s carrying capacity

Equilibrium 

• When the population is maintained at its carrying capacity 

• The population size is at equilibrium (balance) - logistic growth 

Predator-prey relationships 

Predation

• is a biological interaction where one organism, the predator, kills and eats another organism, its prey

• Because the predator relies on the prey as a food source, their population levels are dependent on each other

• If the prey population drops, predator numbers will decrease due to competition

• If the prey population rises, predator numbers will increase due to an over-abundance of a food source

Arctic fox VS snowshoe hare 

Species at risk 

Species at risk 

Biodiversity 

• The variety of life on earth 

• The greatest threat to biodiversity species becoming extinct

Extinct species 

• is one that has died out 

• No longer exists anywhere on earth 

Extinction can result from 

• Natural disasters 

• Overhunting 

• Habitat loss

• Climate changes 

• Poor reproductivity 

Sea mink 

• Lived around rocky coasts of New England 

• Also southernmost Maritime Provinces 

• Until hunted to extinction in the late 19th or 20th century 

Risk categories 

• Committee on the status of endangered wildlife in Canada (COSEWIC)

  • Monitors the status of species  

  • Uses data on extinction species to separate species at risk into four categories

    • Extirpated 

    • Endangered 

    • Threatened 

    • Special concern 

Extirpated 

• Species that no longer exists in a specific area but does appear elsewhere

• Example

  • Paddlefish extirpated in Canada 

  • Grizzly bears extirpated in the prairie provinces 

Endangered 

• Species in immediate danger of becoming extirpated or extinct 

•  Example

  • Caribou

  • North Atlantic right whale 

Threatened 

• Species likely to become endangered if no action is taken 

• Examples 

  • Barn owl

  • Eastern hognose snake 

Special concern 

• Species that may become threatened or endangered because of various factors 

• Examples 

  • Polar bear 

  • Great blue heron 

Invasive species 

• The intro to non-native species to ecosystems by humans is a major cause of species loss 

• Most native species die out because they can’t tolerate an entirely new environment 

• Some species survive because there are few predators or diseases to limit their growth 

An invasive species 

• Is non-native species that have a negative impact on the natural environment 

• Can be accidentally or purposefully introduced 

• Competes with native species for resources 

Niche 

a comfortable or suitable position in life or employment