KEY CONCEPT Every organism has a habitat and a niche.

KEY CONCEPT Every organism has a habitat and a niche.

Objectives • Differentiate between a habitat and a niche • Differentiate between competitive exclusion and ecological equivalents

A habitat differs from a niche. • A habitat is all aspects of the area in which an organism lives. • biotic factors • abiotic factors • An ecological niche includes all of the factors that a species needs to survive, stay healthy, and reproduce. • food • abiotic conditions • behavior

Resource availability gives structure to a community. • Species can share habitats and resources. • Competition occurs when two species use resources in the same way. • Competitive exclusion keeps two species from occupying the same niche.

One species is better suited to the niche and the other will either be pushed out or become extinct. • The niche will be divided. • The two species will further diverge. • Competitive exclusion has different outcomes.

Madagascar South America • Ecological equivalents are species that occupy similar niches but live in different geographical regions.

What are the 3 parts of an organisms ecological niche? • Food type • Abiotic conditions • Behavior

What does the principle Competitive Exclusion say will happen when 2 species compete for the same resource? • One species will be better suited to the niche, and the other species will either be pushed into another niche or become extinct

If a group of mantella frogs were transported to the ecosystem of the poison dart frogs, what might happen to the 2 species populations? • As ecological equivalents, they share a similar niche. • The population better suited to the niche might deprive the other of resources, causing the other to die off. OR • One population might respond to limitted resources by altering its niche.

A bison and an elk live in the same habitat and feed on the same grasses. Does this mean that the competitive exclusion principle does not apply? Expleain. • The competitive exclusion principle only applies if the 2 species live in the same habitat AND occupy the same niche • A niche includes • Food type • Abiotic conditions • Behavior • These two species use the same food resource but occupy different niches

Considering the competitive exclusion principle, why may it be harmful to transport a species such as a rabbit, to another habitat where it currently does not exist? • If a new species is introduced to an area, it may occupy a similar niche as a native species and be better adapted for the niche to have no natural predators. • This could drive the native species to extinction

14.2 KEY CONCEPT Organisms interact as individuals and as populations.

14.2 Objectives • Compare & Contrast interspecfic and intraspecific competition • Describe the 3 types of symbiosis

14.2 Competition and predation are two important ways inwhich organisms interact. • Competition occurs when two organisms fight for thesame limited resource. • Intraspecificcompetition • Interspecificcompetition

14.2 • Predation occurs when one organism captures and eats another.

14.2 • Mutualism: both organisms benefit • There are three major types of symbiotic relationships.

14.2 Commensalism Human Our eyelashes are home to tiny mites that feast on oil secretions and dead skin. Without harming us, up to 20 mites may be living in one eyelash follicle. Ø Demodicids Eyelash mites find all they need to survive in the tiny follicles of eyelashes. Magnified here 225 times, these creatures measure 0.4 mm in length and can be seen only with a microscope. + Ø + Organism is not affected Organism benefits • There are three major types of symbiotic relationships. • Commensalism: one organism benefits, the other is unharmed

14.2 Braconid wasp Braconid larvae feed on their host and release themselves shortly before reaching the pupae stage of development. 0 Parasitism + _ Hornworm caterpillar The host hornworm will eventually die as its organs are consumed by wasp larvae. _ Organism benefits Organism is not affected 0 • There are three major types of symbiotic relationships. • Parasitism: one organism benefits, the other is harmed

14.2 • There are three major types of symbiotic relationships. • Parasitism meet their needs as ectoparasites (such as leeches) and endopaasites (such as hookworms)

14.2 During the fall spawning of salmon, grizzly bears fight over space on the banks of a river. What type of competition is this? • The bears are fighting amongst themselves so it is considered intraspecific competition

14.2 Describe and give an example of the 3 types of symbiosis • Mutualism +/+ • Commensalism +/0 • Parasitism +/-

14.2 How are predation & parasitism similar? How do they differ? • Predation & parasitism are both relationships in which one organism benefits while the other is harmed. • In predation, the predator needs to kill its prey in order to benefit • In parasitism, the parasite benefits by keeping its host alive

14.2 After a lion has made a kill birds will sometimes arrive to pick at the carcass. The birds would be considered _________(A)_________________ while the lions would be considered _________(B)_____________________ • A) Scavengers • B) Predators

14.3 KEY CONCEPT Each population has a density, a dispersion, and a reproductive strategy.

14.3 Objectives • Consider density and geographic dispersal as characteristics of populations • Describe 3 basic types of survivorship curves in relation to reproductive strategies.

14.3 Population density is the number of individuals that live in a defined area. • Population density is a measurement of the number of individuals living in a defined space. • Scientists can calculate population density.

14.3 Clumped dispersion Uniform dispersion Random dispersion Geographic dispersion of a population shows how individuals in a population are spaced. • Population dispersion refers to how a population is spread in an area.

14.3 • clumped • There are three types of dispersion.

14.3 • uniform • There are three types of dispersion.

14.3 • random • There are three types of dispersion.

14.3 Survivorship curves help to describe the reproductive strategy of a species. • A survivorship curve is a diagram showing the number of surviving members over time from a measured set of births.

14.3 • Type I—low level of infant mortality and an older population • common to large mammals and humans • Type II—survivorship rate is equal at all stages of life • common to birdsand reptiles • Survivorship curves can be type I, II or III. • Type III—very high birth rate, very high infant mortality • common to invertebrates and plants

14.3 An Organism has 10 offspring. Two of these offspring die each year over a 5 year period. Is this organism more likely to be a bird or insect? Explain. • The organism is a bird because the mortality pattern described is closest to type II. • Insects tend to be type III, with many offspring and high mortality early in life stages

14.4 KEY CONCEPT Populations grow in predictable patterns.

14.4 Objectives • Describe 4 characteristics that affect population size • Compare exponential and logistic population growth • Identify factors that limit population growth

14.4 Changes in a population’s size are determined by immigration, births, emigration, and deaths. • The size of a population is always changing. • Four factors affect the size of a population. • immigration • births • emigration • deaths

14.4 Population growth is based on available resources. • Exponential growth is a rapid population increase due to an abundance of resources.

14.4 • Logistic growth is due to a population facing limited resources.

14.4 • Carrying capacity is the maximum number of individuals in a population that the environment can support. • A population crash is a dramatic decline in the size of a population over a short period of time.

14.4 Ecological factors limit population growth. • A limiting factor is something that keeps the size of a population down. • Density-dependent limiting factors are affected by the number of individuals in a given area.

14.4 • predation • competition • Density-dependent limiting factors are affected by the number of individuals in a given area. • parasitism and disease

14.4 • unusual weather • natural disasters • human activities • Density-independent limiting factors limit a population’s growth regardless of the density.

14.4 What 4 factors determine the growth rate of a population? • Immigration • Births • Deaths • Emigration

14.4 How does carrying capacity affect the size of a population? • Carrying capacity limits the size of a population

14.4 What is the main difference between a density-dependant limiting factor and a density-independent limiting factor? Give an example of each. Density-Dependant Density-Independant A density independent limiting factor is not affected by population size/density These are usually ABIOTIC limiting factors such as Weather Forrest fires Natural disasters Human activities • A density dependant limiting fact is affected by the number of individuals in a given area • These are usually BIOTIC limiting facto=rs such as • Predation • Competition • Disease

14.4 What might cause exponential growth to occur only for a short period when a new species is introduced to a resource filled environment. • Eventually, the growing population will consume all the resources, and the species may experience a population crash.

14.4 Give an example of how a symbiotic relationship could cause a population to crash. • If a parasite or disease spreads in a dense population, it could cause a population to decline dramatically over a short period of time.

14.5 KEY CONCEPT Ecological succession is a process of change in the species that make up a community.

14.5 Objectives • Describe the process of primary succession • Explain the difference between primary and secondary seuccession

14.5 Succession occurs following a disturbance in an ecosystem. • Succession regenerates or creates a community after a disturbance. • a sequence of biotic changes • damaged communities are regenerated • new communities arise in previously uninhabited areas

KEY CONCEPT Every organism has a habitat and a niche.