Introduction To Communities

Introduction To Communities

Communities

• It is rare in the environment that a species will exist in a population

• Normally there are other living factors that are in the environment

Communities

• Remember that communities are all of the collective organisms in a given area

• Understanding how these organisms interact with each other can drastically affect the way that each organism survives

Communities

• There are 6 basic interactions between different organisms in a population – Predation– Herbivory– Competition– Mutualism– Commensalism– Parasitism

Name Effect On Species #1

Effect On Species #2

Predation + -

Herbivory + -

Competition - -

Mutualism + +

Commensalism + 0

Parasitism + -

Predation

• Now it is time to explore the relationships between organisms

• One way that a community can interact is through predation and herbivory

• In predation, one species will eat all or some of another species

Predation

• Most people often think that predators are animals that eat other animals

• However, predators can be herbivores

• Herbivores eat other organisms and should therefore be considered predators

Predation

• Any organism that is eaten is considered prey

• Prey organisms often spend a large amount of their life trying to avoid predation

Predator Adaptations

• Predators that happen to be the best suited to find and consume their prey are the ones that survive

• Rattlesnakes are animals that have an excellent set of adaptive advantages that influence prey

Predator Adaptations• Rattlesnakes have an

excellent sense of smell which they use to find their prey

• Rattlesnakes also have a very strong venom that can be injected into prey animals

• The jaw of the rattlesnakes can unhinge in order to eat large prey

Predator Adaptations

• A humming bird is a well adapted predator

• A humming bird consumes the nectar of plants

• It can beat its wings 10 to 15 times a second

• It can also hover in mid air to drink nectar from flowers

Videos

• http://www.youtube.com/watch?v=j3mTPEuFcWk

• https://www.youtube.com/watch?v=FiJln5f1Mus

• http://animal.discovery.com/videos/fooled-by-nature-hammerhead-shark-hunting-methods.html

Adaptations in Animal Prey

• Prey animals may do one of many things when a predator approaches

• There goal is to not be eaten

• They will use what ever natural abilities they have in order to survive

Adaptations in Animal Prey

• Some animals run and hide as fast as they can

• These animals are built for speed and agility

• As long as the prey animal is faster or more agile then the predator they should be able to survive

Adaptations in Animal Prey• Some animals have false

markings or spots that will confuse a predator

• The predator might get confused when there is a large group of an animal and not be able to pick out one

• Sometimes the markings resemble extra eyes or heads so the predator does not know where the animal is facing

Adaptations in Animal Prey

• Some animals hide in plain sight

• These animals often try to resemble an object that is inedible

• They display a form of camouflage that makes them look like their surroundings

Adaptations in Animal Prey

• Some animals have chemical defenses

• These defenses can taste or smell terrible or can be deadly

• These organisms often have distinct markings and bright colors that let predators know they have chemical defenses

Adaptations in Animal Prey• The final strategy is the

mimic a much more deadly animal

• Mimicry is when the prey animal will mimic the look of an animal that can defend itself from predators

• When a predator sees the animal it will not want to attack it

Adaptations in Animal Prey

• http://www.youtube.com/watch?v=sfENSyycPQ4

Adaptations in Plant Prey

• Plant prey organisms have to defend themselves differently

• Plant prey organisms cannot run from their predators so they normally have different defenses

Adaptations in Plant Prey

• Some plants develop physical defenses

• These defenses are normally spines, needles, thorns or sticky leaves

• These prevent animals from eating them or attempting to get too close to them

Adaptations in Plant Prey

• Plants have also developed a variety of chemical defenses

• These can be a poisonous sap, bad taste or irritating rash

• These plants are often avoided by predators because of the side effects of eating them

Adaptations in Plant Prey

• http://www.howcast.com/videos/22122-How-To-Recognize-and-Avoid-Poison-Ivy

• http://www.metacafe.com/watch/3129772/mighty_milkweeds/

Competition

• Competition may be a good thing on a soccer field

• Generally it brings out the best in two organisms that are competing for a starting spot

• However it works quite differently in the wild

Competition

• Interspecific competition is when two different species compete for the same limited resource

• Since resources are limited two different species will compete for the resources

http://www.youtube.com/watch?v=84bBzAxLXFY

Competition

• Lions and Hyenas often will compete for the same prey

• Because there are a limited amount of Wildebeests and Zebras Lions and Hyenas will compete over who gets to eat them

Competitive Exclusion• Competitive exclusion is

when one species uses a limited resource much more effectively than another species

• When this happens, the one species that uses the limited resources more effectively will survive and prosper

• The species that does not use the resource as effectively will have drastically lower numbers and my even die out

Competitive Exclusion• We can see competitive

exclusion If we put two different type of bacteria in a test tube that share the same niche

• After a small amount of time we will see one bacteria have a much higher population

• The other bacteria will have a much lower population and will possibly be extinct

Niche Size

• A niche is an organisms role in its environment

• Many different types of organisms can fill different roles in the environment basted on what they do, where they live and when they are active

Niche Size

• An organism’s niche can be broken up into more manageable chunks

• A fundamental niche is the complete range of environments that an organism can live in

• A realized niche is the part of the niche that the species generally use

Character Displacement

• It is better for predators to be different from one another

• If they share too much of the same niche, the predators have a chance of being out competed through competitive exclusion

Character Displacement

• The finches that live on the Galapagos Islands are an excellent example

• They are all Finches but they all have different beaks they help them do different things

• They do not share the same realized niche

Character Displacement

• The less similarities among a community, the less chance that a species will die out

• The process of predators changing over a period of time is called character displacement

Resource Partitioning• Some predators are in the

same area and competing for the same food

• When they compete for the same food, it is important to consider where the resources are being used

• The differences in location between where predators hunt for a similar resources is called resource partitioning

Resource Partitioning

• The actual separation of the species makes a more defined realized niche

• All of these species are eating a particular type of bug out of a particular tree

• However, they are hunting in a different area

Symbiosis

• When groupings of organisms are in a close proximity for a long time they can develop relationships

• Symbiosis is a long term relationship between two different species

Symbiosis

• There are three different types of symbiosis

• There are– Parasitism– Mutualism– Commensalism

• These three describe what happens when organisms are develop a close relationship

Symbiosis

• Remember that all three of these share some basic qualities, however they all affect different species in different ways

• These different interactions can be good or bad for the species involved

Parasitism• Not all relationships are

beneficial to all parties involved

• Sometimes there are two organisms in a relationship where only one gains a benefit and one is harmed

• Parasitism is when one organism (host) is harmed and one organism (parasite) gains a benefit without immediately killing the host

Parasitism

• Parasites can attack a host in a variety of ways

• When parasites attempt to harm another organism from the outside of the body they are called ectoparasites

• Good examples of this are fleas, leeches, aphids and ticks

Parasitism• Parasites that live inside

of the host are called endoparasites

• These parasites live inside of their host in the various organs of the body

• Examples of this are heartworms, disease causing protists and tapeworms

Videos

• https://www.youtube.com/watch?v=iy0RuWApYO0

Mutualism

• Not all close relationships are negative

• When both organisms gain some sort of benefit out of a relationship it is called mutualism

• This beneficial relationship is seen many places in nature

Mutualism• Probably the most

important mutualistic relationship on Earth is between bees and flowers

• Flowers provide food for bees in the form of nectar or pollen

• Bees carry the reproductive materials for the flower from plant to plant

• This allows them to reproduce

Video

• https://www.youtube.com/watch?v=Xm2qdxVVRm4

Commensalism• Sometimes some organisms

have an affect on another organism without a benefit to themselves

• Commensalism is when one organism benefits and one organism has not affected

• Scavengers are good examples of organisms that have commensalism relationships

Commensalism• A good example of this is

water buffalo and cattle egrets

• When water buffalo move around as a herd they often scare many bugs, small mammals and small lizards

• The cattle egrets follow the buffalo and eat the small animals they scare

Video

• https://www.youtube.com/watch?v=IrE05fvMx_o

Types of Organisms• Most plants create glucose

from the sun in a process called photosynthesis

• Photosynthesis makes up the largest part of the food web because there are many more producers than consumers in any food web

• There are rare food webs where photosynthesis does not make up the production level of the food web

Types of Organisms

• There are a very wide variety of organisms that are consumers

• As small as a bacteria and as large as a whale

• All consumers are heterotrophs

• Less predominant than producers

Types of Organisms

• Dead plant material, fecal wastes and dead animal bodies make up a large amount of energy

• That energy can be used by Detritus Feeders

Types of Organisms

• Decomposers are a particularly important group of detritus feeders

• Decomposers are animals that “rot” dead organic matter– Bacteria and fungi make

up this group

Trophic Relationships

• All food levels on the trophic levels are interconnected

• The different levels in the food web are called trophic levels

• Trophic refers to food or feeding

Trophic Relationships• In a food web there are

normally no more than three or four levels

• This is because there are different levels in biomass

• Biomass is a measurement of the weight of all the organisms at a particular step in the food web

Trophic Relationships• The amount of biomass can

often be represented by a trophic pyramid

• This is a visual representation of the amount of biomass in a system

• Only ~10% of the biomass (or energy) in a level of the biomass pyramid is transferred to the next level

Trophic Relationships

• This is because much of the energy consumed from an organism cannot be absorbed

• Out of the energy that is absorbed, around two thirds of it is used in cellular respiration

• The remaining energy is used for growth, reproduction and production

Trophic Pyramid