Types of Natural selection - PowerPoint Presentation

Slide1

Types of Natural selectionSlide2

Wednesday 1/22/14

Grab a book and a new

bellringer

so you are not TARDYLT: I can identify types of selectionBR: What is natural selection?** if you finish bellringer begin & finish vocab for day 2. We will begin class 10 min after bell rings. Day 2 is due on Tuesday

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Friday 1/24/14

Study day 2 vocab for quiz on Monday

Continue day 3 vocab

Finish worksheet for lab yesterdaySlide4

natural selection

is the process by which individuals that are better adapted to their environment

survive

and reproduceWhat have we been studying in class so far how does it connect

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Evolution by Natural Selection

Steps:

Individuals vary in some traits.

2. Some of the differences in traits are passed along to offspring.

This requires a genetic basis to the trait

The trait is thus

heritable

(more…)

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Evolution by Natural Selection

3. Different individuals produce different numbers of surviving offspring.

Produce different numbers,

orDifferent numbers survive.

4. The particular value of a trait is connected to the number of offspring produced.

Traits that allow for more offspring to be produced are said to be “naturally selected.”

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evolution

Evidence of evolution

Natural selection

Genes

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Types of Natural Selection

Directional

– The most extreme form of a trait is favored and becomes more common

Disruptive- 2 extreme forms of a trait are selected forStabilizing-The average form of a trait is favored and becomes more common

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Example 1

The tall man virus has taken over the country. It only infects men over the height of 6 feet. Scientists are scrambling to find a cure. This is an example of what type of selection. Draw the appropriate graph that goes with it.

Directional because it selects for one extreme of the population. Thus the allele for short men will continue on while the allele for tall men are being selected againstSlide10

Example 2

Clutch Size in

Birds:

Females that lay intermediate numbers of eggs have the highest reproductive success. Too many eggs, and the offspring all starve. Too few eggs, and the mother could have laid more. Called the Lack optimum, it applies to many birds.Stabilizing because individuals with the average trait have the highest fitness. Slide11

Example 3

A population of rabbits consist of black, white and gray fur color.

If

this population of

rabbits

were put into an

area

that had very dark

black

rocks

as well as very

white

colored

stone

, the

rabbits

with

black

fur

would be able to

hide

from

predators

amongst the

black

rocks

and the

white

furred

rabbits

would be able to

hide

in the

white

rocks

, but the

gray

furred

rabbits

would

stand

out in both of the

habitats

and thus would not survive

.

What type of selection is this? Draw the appropriate graph that goes with it.

Disruptive because it is selecting for the individuals with either extreme of the trait. Slide12

Example 4

Infants with average birth weight are more likely to survive than a baby that is too small or too large. The bell curve peaks at a birth weight that has the minimum death rate

.

What type of selection is this? Draw the appropriate graph that goes with it. Stabilizing because individuals with the average trait have the highest fitness. Slide13

Example 5

Salmon migrate to the rivers they were reproduce at approximately the same time every year. Fisherman know this and fish for salmon at this time. However a population of fish arrive earlier than the other salmon. This earlier population has been growing larger every year while the later population has been growing smaller. What type of selection is this? Draw

the appropriate graph that goes with it.

Directional because it selects for one extreme of the population. Thus salmon that mate at an earlier time of the year are being selected for. Slide14

Example 6

The giraffe population at one time was made up of giraffes with different neck sizes, short, medium, long. However, tree heights only got taller and taller until there were no short trees to eat from. Over time the short neck giraffes died and only long neck giraffes survived. What type of selection is this?

Draw the appropriate graph that goes with it.

Directional because it selects for one extreme of the population. Thus the allele for short necks will not continue on while the allele for tall necks are being selected

forSlide15

Example 7

imagine a plant of extremely variable height that is pollinated by three different pollinators, one that was attracted to short plants, another that preferred plants of medium height and a third that visited only the tallest plants. If the pollinator that preferred plants of medium height disappeared from an area, medium height plants would be selected against and the population would tend toward both short and tall, but not medium height

plants. What

type of selection is this? Draw the appropriate graph that goes with it. Disruptive because it is selecting for the individuals with either extreme of the trait. Slide16

Example 8

The desert population of spiny cacti are under attack. Peccaries are eating those plants with

low-spine-numbe

r. A second predator, a parasitic insect, arrives in the study area. Preferring densely spined cacti, these egg-laying parasites more often destroy varieties of plants with larger numbers of spines. The only cacti left are those with a moderate amount of spines. What type of selection is this? Draw the appropriate graph that goes with it.

Stabilizing because individuals with the average trait have the highest fitness. Slide17

Example 9

A population of birds with small medium and large beaks exists. The birds with small beaks can only eat small seeds, the medium beak birds can only eat medium seeds and the large beak birds can only eat large seeds. The plants that provide medium seeds dies out and thus the medium beak bird population dies off. What type of selection is this and draw the graph that goes with it.

Disruptive because it is selecting for the individuals with either extreme of the trait. Slide18

anatomy

study of structure of body: the branch of science that studies the physical structure of animals, plants, and other organismsSlide19

embryology

The scientific study of embryos and their developmentSlide20

BIOGEOGRAPHY

The study of geographical distribution of living thingsSlide21

Wednesday 1/22/14

LT:

I can

Analyze data from an activity and explain how it supports the theory of natural selection citing evidence from the data. BR: List the three types of selection and give examples of each.

** Quiz Thursday

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Thursday 1/23/14

LT:

I can

Analyze data from an activity and explain how it supports the theory of natural selection citing evidence from the data. BR: Does natural selection create the perfect organism? Explain your choiceDay 2 vocab quiz tomorrow Slide23

Peppered moth simulation

A few changes to the lab

Number of moths

will be 15 for the starting populationTime to pick up moths will be 20 secondsDon’t sigh or your moths will fly away!! Watch your sleeves because the moths will escape with your clothing!!!

This will be graded! Do your best as you always do!Slide24

Monday January 27, 2014

LT: I can design a species and relate it’s adaptations to it’s overall FITNESS

BR: what does FITNESS mean?

** vocab quiz get a chrome book and study!!Slide25

Tuesday 1/28/14

LT: I can

research

a species and relate it’s adaptations to it’s overall FITNESSBR: what is the weirdest animal you have ever seen or heard of?