Lecture 3

BIOL1000A S2015

Food Selection The Driver of Trichromatic Evolution?

HOW DID THIS HAPPEN?

There are three types of opsins: Short Wave Sensitive (SWS) Medium Wave Sensitive (MWS) Long Wave Sensitive (LWS)

An individual possessing only SWS and MWS opsins will have DICHROMATIC vision.

An individual possessing SWS, MWS and LWS opsins will have TRICHROMATIC vision.

Where did the third opsin (LWS) come from?

Random genetic mutation

Selection

What is Selection?

Selection occurs when some force or phenomenon affects the survival of

individual organisms.

Russell et al (2010)

Impacts the population

Levels of ecological scale

Population group of individuals from same species that live in same area & regularly interbreed

Evolution of the camera eye

Fig. 1.15

Simple Complex Eyes

Eye spot e.g., Euglena

Eye cup e.g., Planaria

Pinhole eye e.g.,Nautilus

Primitive lens e.g., Box jellyfish

Evolution of Eyes

Mollusca (e.g. clams, snails, octopus): Share common ancestor Simple to complex eyes found.

Limpet simple layer of photosensitive cells

Slit-shell snail simple layer of photosensitive cells curved in eyecup

Nautilus pinhole-camera eye

Squid advanced camera eye

Cephalopod

How does light impact behaviour?

Refer to Chapter 1 for examples

Circadian Rhythms and Light

Fig. 1.20

What happens when external cues

do not match the circadian rhythm?

Fig. 1.25

Resetting the circadian rhythm

Fig. 1.24

Role of Light in Behaviour and Ecology

Fig. 1.26, 1.27

Signals Mate attraction Pollination (read text)

The Detriments of Light

DNA damage

Thymine dimer formation Change the DNA structure Prevents DNA replication at that point in the DNA

Fig. 1.18

DNA damage

Fig. 1.18

What could happen if DNA is damaged?

Think about all the potential implications.

Can the DNA be repaired and if so how?

What is the other detriment of light outlined in the text?

Pygmy Seahorse

Pygmy Seahorse

Pygmy Seahorse

Taxonomic Organization Taxonomic rank

Domains

Fig. 3.20

See Aplia Course Materials-> Biology Videos, Animations and Figures ->Defining Life and Its Origins-> Figure 3.20.

Bacteria (e.g. E. coli)

prokaryotic cell circular DNA within nucleoid (chromosomal region) lack internal membranes

Fig. 20.3

Archaea

recently determined to be evolutionarily different from bacteria look like bacteria but...... at molecular level are more related to Eukarya

Many archaea live in extreme conditions

Cold-dwelling

Crenarchaeota in

Antarctic Peninsula

Domains

Fig. 3.20

See Aplia Course Materials-> Biology Videos, Animations and Figures ->Defining Life and Its Origins-> Figure 3.20.

Random genetic mutation

Selection

http://evolution.berkeley.edu/evolibrary/article/_0/bergstrom_03

http://www.ottawacitizen.com/business/Super

bugs+thrive+overcrowded+hospital/3471380/

story.html

http://evolution.berkeley.edu/evolibrary/article/_0/bergstrom_03

How do we get a resistant variety?

Artificial Selection

How does selection contribute to evolution?

What is Evolution

A slow and gradual change in the characteristics of

organisms over time

random genetic mutations contributes to evolution selection contributes to change and thus to evolution

Why should we care about evolution?

Evolution Major Unifying Concept of Biology

Generation 1

Some evolutionary

process

e.g., natural

selection

Generation 10

A change in the traits of a population over

time

EVOLUTION

Hypothesis: early stages of an idea or a model

Theory: hypothesis widely accepted by the scientific community via rigorous experimentation and re-testing (replication) with same results.

WHY is my flashlight is not working!

hypothesis is: specific to the question testable and falsifiable based on knowledge

WHY is my flashlight not working?

See Purple Pages F2-F5 for text example

Theory Everyday Use vs Science

IT IS JUST A THEORY! Impliesuntested speculation.

(e.g. In theory, she should do fine in the course)

THEORY in science Broad explanation based on many lines of evidence.

Aids in the generation of many new hypotheses. Has withstood rigorous scientific testing.

(e.g. Natural selection is a method of evolution.)

Two major unifying concepts of Biology

1. Theory of Evolution by Natural Selection

Characteristics of a population change over time. (pattern)

Individuals with certain heritable traits produce more offspring than those without those traits. (mechanism)

2. Cell Theory

Theory of evolution

Explains the unity and diversity of life.

Darwins theory of evolution: Since species are highly fertile, they make more offspring than can grow

to adulthood.

Food resources are limited, but should remain relatively constant as time progresses.

In a species that sexually reproduces, it is likely that no two individuals are identical. A great deal of variation exists.

This variation is inherited so favorable traits are passed on to offspring.