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7/29/2019 BIOL1070 Guelph

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Biodiversity 1/9/2013 8:27:00 AM

Introduction

Biodiversity is the variety of genes, species and ecosystems Shaped by billions of years of evolutionary history of interaction

between environments and life forms (natural phenomenon, otherspecies, etc.)

Human activity can have lasting impacts at large scales that aredifficult to predict

Descent with modification from common ancestorsMussels

What factors contribute to the threats to native freshwater musselbiodiversity in the Great Lakes Region?

o MASS PROPAGATION OF MUSSELSo POLLUTIONo HUMAN IMPACTSo INVASIVE SPECIESo POLLUTIONo OVERFISHINGo TEMPERATURE FLUCTUATION


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Bivalves develop in 3 ways (Ontogenic Variation; not all freshwater mussels

develop in the same way)

By passing early development as a parasitic stage on a host(Unionids)

By producing veliger larvae ( in Dreissena polymorpha) By releasing fully developed young mussels (rare) Dioeceous (Male and female; both genders) Production: releases sperm from the exhalant siphon, female takes

in sperm from the inhalant siphon; female now has sperm and egg

in the same area internally; once the egg is fertilized it is an

embryo, the embryo is then held within a little chamber within the

gills called a marsupium; those embryos develop and then release

Glochidia which attach to a fish gills by clamping down onto the

finger-like gill extensions, suck nutrients out of the blood of the

fish; Eventually leave the fish and grow till the become a full sized

adult)

Glochidia

Cannot swim or crawl Attach to host fish gills Sometimes release a few million of these glochidia


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As few as 10 out of a million can attach to a fish gillStrategies for Infection

Using Lures to attract the fish (modified mantle tissue that mimicsfish or invertebrate prey to attract fish host)

Conglutinate : a membranous sac that is released by the mussel,attached by a thread that is filled with glochidia

Host capture: Mussel may physically grip host and pump glochidiaover the gills (snuffbox mussel)

Veliger Larvae

Trocophore (stage at which larvae are released into the watercolumn)

Veliger larvae that can move in the water and are carried a longdistance away and do not require a host to complete their life cycle

Go under metamorphosis after the Pediveliger stage to form ajuvenile

Starts are Embryo, embryo becomes veliger larvae, undergoessome transformations and undergoes complete tissue and structure

metamorphosis into a juvenile settled larvae until it grows into an


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adult (think of a tadpole -> Frog; lungs develop, loses fins and gills,

gains limbs)

Biological Variation

A secondary source of genetic variation is Recombination

Gene Flow: Movement of genes among populations that brings variation into

a population

Genetic Drift: Evolution By chance due to a random event . Random changes

in allele frequencies due to chance.

Can cause the population bottle neck, when a population is severelyreduced in size. Loss of individuals not related to particular traits

(happens at random) usually because of a catastrophe of some

sort.

Founder effect is the loss of genetic variation that occurs when anew smaller population is established.


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Natural Selection

Variations useful to any organic being do occur, assuredlyindividuals thus characterized will have the best chance of being

preserved From the principle of inheritance they tend to produce offspring

similarly characterized this principle of preservation is called Natural

Selection

If useful allele appears it is passed on and with time allelefrequency for this allele increases.

Heritability and Overproduction are key components of naturalselection as well as variation in alleles

Mutations

Mutations are random Good, bad and neutral mutations happen with equal probability Beneficial mutations increase in frequency and deleterious once

decrease in frequency under natural selection (Change in proportion

of mutations is non-random under natural selection)

Mussel Anatomy

Surface area of gills is high, these Mussels have to extract oxygenfrom the water

Water is drawn in through the inhalant siphon and passes over thegills and then water is expelled from exhalent siphon

All molluscs have mantle but within the phylum there is greatdisparity

Mantle: Folding of the body wall that lines shell and secrets shellsubstance (CaCO3) and houses gills

Note: Adaptation is the evolutionary change over thousands of generations,

enhances survival and reproduction through natural selection

Co-option of a functional tissue into a new and additional function.(I.E: Mantle -> Complex lure)

Extirpated: Disappeared from a region, but not extinct yetExtinction


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Failure to adapt to a changing physical environment or find a newsuitable habitat (Not enough variation? No gene flow?)

Failure to keep up with the evolution of a competitor, predator, hostpathogen, etc.

Being driven to extinction by a newly encountered competitor,pathogen, or predator

Losing an essential host , prey, or partner speciesHOW DO THESE RELATE TO MUSSELS?

What matters most for speciation is that there is a barrier to gene flow,

which allows one species to split into two. What kind of Barriers?

New Rivers, mountain building, continental drift, reproductivebiological barrier, behavior

Allopatric speciation (different place) : Species is split due to ageographic barrier or because some individuals move to a separate

place. Through natural selection have evolved and changed, the

animals that are moved away can no longer breed together and are

not compatible. When viable offspring cannot be created, they are

now different species.

Sympatric speciation (same place): Species is split by reproductiveseparation without any geographic barriers. For example Maggots

were only laid on hawthorns, 200 years ago immigration brought inapple trees, now the maggots are laying eggs on apple and

hawthorn trees 2 populations begin to differentiate a lot because of

the different locations that the maggots are born on. Maggots born

on apple trees only like apples, maggots born on hawthorns prefer

laying eggs on hawthorns.

Hypothesis Definition

Hypothesis: A proposed explanation for a fairly narrow set ofphenomena, usually based on prior experience, scientific

background knowledge, preliminary observations, and logic.

A testable statement about the natural world that can be used tobuild more complex inferences and explanations.


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Measuring Ecosystem Diversity

Identify the species in the area with a dichotomous key Ecosystem diversity includes the variety and relative abundance of

species

To measure we must define what organisms are sample, the spatialarea sampled and when/how long we sampled (time)

Abundance is a higher amount of individuals Seasonality is also an important figure, depending on what time of

year you go out (I.E: you wont find very many butterflies in the

winter)

How long you spend in the environment and how much effort youput in

The number of species per specified collection/sample area ORspecified number of individuals

D is the correct answer.

Evenness: Relative abundance of species in an area (Shannons Index)

(2 pine: 2 Spruce: 2 Oak = High Evenness) ; (3 Pine; 5 spruce; 1 palm =

Low Evenness)

Woodlot

A forest in a city (urban forest) Remnant forest in a farmers field Start off with a canopy and a dominant canopy that sticks over all

the others (a Supercanopy).


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Sub canopy: which could be shrubs Open area : forest floor Process: Not a lot of organic layer left in the forest floor Nutrient fallout comes through the leaves; lichens and mosses add

nutrients to the ground

Ecosystem

A system formed by the interaction of a community of organismswith their physical environment

Ecosystems can be large (Canadian boreal forest ) or small (apond)

Temperature Deciduous Forest Biome

Seasonal variation in mean temperature (5-20 degrees Celcius) Precipitation is even among the season (80-120cm/yr) Deciduous trees dominate Dominate because they outcompete conifers in summer because

large leaves = greater photosynthetic capacity

Why do deciduous trees lose their leaves in the fallo

Why dont coniferous trees dominate wherever this is a winterseason?

o Time for growing season (In spring, deciduous have to regrowtheir leaves and it takes time to photosynthesize, in the

spring, in the northern part of Ontario conifers can starts

producing energy right away, once the deciduous trees have

dropped their leaves theres no more chances to capture

energy whereas Conifers can turn on the machinery at any

time.

What kind of Trees are found in tropical regions?Old Field Woods Majestic Pine

Woods

Maple Ridge

Woods

Forest Age 20 80 250

Soil/water table Shallow soil with Deep organic soil Shallow organic


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mineral soil of

sand and clay.

Shallow water

with sandy

mineral soil.

Medium Water

layer with sandy

mineral soil.

Deep water

Woody Plant

Diversity

Very High Medium low

Birds High Medium low

Physiognomy Shrub dominated Trees Trees

Invasive Species Giant Hogweed

Nuisance Species Raccoons/ Skunk

Endangered

Soecues

Population One species Number of individuals (abundance) Geographic distribution = area in which individuals occur Growth (increase or decrease in abundance over time)

Community

A community is composed of multiple species within an area Number of species (diversity) Trophic structure (plants, herbivores, carnivores) Composition (Abundance, evenness, dominance [one species

dominating over others])


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D is the answer. B is talking about POPULATION not COMMUNITY.

What Ecological Factors place limits on a species geographic range?

Dispersal (Nuts falling from a tree, spores from fungi) Biological Interactions (Dependence on animals around them e.g.

parasites, symbiotic relationships, host-dependence)

Habitat selection (Particular environments during life cycles thatmay limit where they are going to be, where birds decide to nest,

etc.)

Abiotic Factorso Climate (temperature, moisture)o Geology (rock type, land formations)


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o Soil minerals, texture (silt, sand, clay), acidityo Light (sun, shade)o Nutrients (Nitrogen, Phosphorus , Potassium)o Pollutantso And otherso Interconnectedness between abiotic factors (Soil influences

nutrients, geology influences soil, moisture influences

nutrients, etc.)

How do Abiotic Factors influence the distribution of Plants and Animals?

Restrict access to resourceso Food/Nutrientso Habitat

Limit Physical Toleranceso Hot/coldo Chemistry (toxins; heavy metals in soils [some plants can

take them and sequester them away and survive])

Physical barrierso Rivers, Mountains, lakes, oceans

How would you determine which abiotic factor is limiting the distribution of a

species? Field observation of actual range distribution Determine ecological tolerances Experiments (field transplant, controlled environment)

o Transplanting trees into ranges until you get into a pointwhere you can no longer transplant them

Correlation between environmental gradients and a speciesoptimum range (Birds dont go past a line)

Transplanting


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Light Water % Survival

A Low Low 90

B High High 44

C High low 19

Light is the key factor

Niche


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Niche is the set of biotic and abiotic conditions in which a species isable to persist and maintain stable population sizes

Or A niche consists of all the factors necessary for a speciesexistence in terms of time, space and required resources

Fundamental Nicheo All the possible dimensions in which a species can survive in

principle

Realized Nicheo The dimensions in which a species actually survives after the

effects of biotic interactions

Niche Differentiationo (In terms of Finches) Natural selection for bigger and

smaller beak sizes due to competition for food

Community Assemblageo Development of ecological niche in a forest along a gradient

of time (or Succession)

Symbioses

Commensalismo One organism benefits the other organism is unaffected

Mutualismo Both Organisms benefit

Parasitism / Predationo One organism gains nutrients and energy the other organism

is injured or killed


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