Bio Module 1

Lectures 1-7

Evolution

Changes in the heritable traits of a biological population over generational time

Genotype

Information stored in DNA

Gene

A segment of DNA that contains the instructions for building a specific protein or preforming a particular function

Phenotype

All structures, processes, and behaviors of an organism

Trait

Facet of the phenotype

Heritable trait

A trait encoded by genes that is inherited across generations

Population

A group of organisms from the same species, existing at the same time in the same space

Evolution acts on __, individual organisms __ evolve

Populations, do not

Generation

Organisms within a population that consist of a single step in line of descent from an ancestral cohort

Evolution happens __ __ as __/__ generate and accumulate within a population

Over time, variations/changes

Altered DNA sequence (mutation)

A random change in the sequence of an organism’s DNA. The only source of new genes, which only sometimes affects the phenotype.

Gene flow

Migration of random individuals (and their genes) between populations
(ex. no antlers vs antlers)

Genetic drift

Random changes in the gene pool of a population
(ex. bottleneck)

Natural selection

Differential survival of individuals with certain heritable traits, but not others
(ex. eaten/starved)

Sexual selection

Differential reproductive success of individuals with certain heritable traits but not others

Evolution has no goal or conscious intention. T of F

T

What limits evolution?

Trade-offs

Trade-offs

Limitations of energy and materials

What limits evolution?

Genetic lineage

Genetic lineage

Limited to modifying pre existing traits in population

Homologous structures

Structures that share the same evolutionary and developmental history

Analogous structures

Structures that look similar and/or perform similar functions, but have different evolutionary and developmental histories

Is it an organism? Virus

1. Cooperating biological units (proteins/nucleic acids)

2. Cannot grow

3. No metabolism

4. Cannot reproduce w/o host

5. Can evolve

NO

Is it an organism? Bacterium

1. Single cells & Cooperating biological units (proteins,nucleic acids,some organelles)

2. Can grow

3. Has a metabolism

4. Most can reproduce w/o host

5. Can evolve

YES

Is it an organism? Jellyfish

1. Multicellular & cooperating biological units (cells,tissues)

2. Can grow

3. Has a metabolism

4. Can reproduce w/o host

5. Can evolve

YES

Is it an organism? Siphonophore

1. Colony of indv & cooperating biological units (zooids)

2. Can grow

3. Has a metabolism

4. Can reproduce w/o host

5. Can evolve

NO

Zooid

Single, multicellular animal that forms part of a larger colonial organism where multiple indv are physically or physiologically connected

Evolution

Changes in heritable traits of a biological population over generational time

Evolution charcteristics

• Has NO goal or conscious intention

• Happens over time within a population

• Limited by trade-offs and genetic lineage

Phylogenetic tree

Hypothesized evolutionary relationships based on shared derived traits

Derived trait

A new trait that evolved from an old trait

Phylogenetic trees characteristics

• Gives extinct groups same worth as living

• No implied goal

• Can be biased

Operational taxonomic units (OTUs)

A,B,C,D,E,

*purple box

Nodes & branches

Show relationships; trees can rotate around nodes

*Green circle | Blue box

Synapomorphy

A shared derived character; can be mapped onto branches & distinguishes a clade from another organism

*Red line

Monophyletic group

A single common ancestor and all descendants

*Purple shaded box

Sister taxa

The next most closely related group to a monophyletic group

*Blue shaded box

Out group

Most distantly related out of all groups

*Yellow shaded box

Parasomy

Preferred explanation for patterns in data is the simplest explanation

3 domains in the phylogenetic tree: Eukaryota

1. Eukaryotic

2. Varying sizes

3. Some single cells, some colonies, some multicellular

3 domains in the phylogenetic tree: Archaea

1. Prokaryotic

2. Small

3. Single cells, some colonies

3 domains in the phylogenetic tree: Bacteria

1. Prokaryotic

2. Small

3. Single cells, some colonies

Diffusion

Net movement of particles from an area of higher concentration to an area of lower concentration

*Passive, move materials within and in & out of cell

Viscous

Fluid that is thick, sticky, and resists flowing easily

Diffusion depends on 4 key factors:

1. Distance needed to travel between two points

2. Difference in concentration of material

3. Surface area where transport can occur

4. “Diffusion coeff” other affecting factors

Fick’s Law equation

What is x in Fick’s Law

Distance needed to travel between two points

*Larger distance = slower rate of diffusion

What is A in Fick’s Law

Surface area where transport can occur

*More SA = faster rate of diffusion

What is delta concentration in Fick’s Law

Difference in concentration of material

*Bigger difference = faster rate of diffusion

Fick’s Law definition

Regulates the movement of nutrients and waste in both single-celled organisms as well as between cells in multicellular organisms

Prokaryote: Def

Organism composed of cells that lack a membrane bound nucleus and other membrane bound organelles

Prokaryote: How do cells divide

Binary fission (asexual)

Prokaryote: Characteristics

• Small

• Unicellular

• No membrane bound organelles

Lateral/Horizontal gene transfer

Transfer of genetic information from one individual to another

Bacteria: Characteristics

1. Cell wall

• contains peptidoglycan

2. Movement

• Flagella

3. Diversity

• Limited morphological diveristy

• High biochemical diveristy

Flagellum

Long, whip-like structure that extends from the cell and propels it

Archaea: characteristics

1. Structures surrounding cell membrane

• Protein surface layer

• Pseudopeptidoglycan

2. Movement

• Archaellum

3. Diversity

• Limited morphological diversity

• High biochemical diversity

Are archaea monophyletic

NO

• Eukaryotes evolved from within archaea

Eukaryote: characteristics

1. Size and organization

• some unicellular, some from colonies, some multicellular

2. Cell structure

• NO peptidoglycan cell wall

• YES membrane-bound organelles

3. Diversity

• LESS biochemically diverse

• HIGH morphological diversity

Endosymbiosis

One cell engulfs another without digesting it (gives rise to a symbiotic relationship)

Eukaryote: Origin

Arose from an endosymbiotic event between archaea and bacteria

Eukaryote: Characteristics

1. Cell walls

• DO NOT contain peptidoglycan

2. Movement

• Cilia or flagella

3. Cell structure

• HAVE membrane bound organelles

4. Diversity

• High morphological diversity

• Low biochemical diversity

Reynolds numbers

Dimensionless number (no units) that describes how an object or organism moves through a fluid

Low reynolds number

• Very small organisms and/or slow movement

• Forces dominated by viscosity

• Flow orderly and reversible

High reynolds number

• Larger organisms and/or fast movement

• Forces dominated by velocity

• Flow disoriented

Rate of diffusion depends on __

Surface area

Surface area (2) and volume(3) __ grow at the same rate

DO NOT

Modifying supply and demand: Increased supply (SA)

Changes overall shape to inc SA : V ratio

*Spheres’s lowest SA/V ratio

Modify supply and demand: Decreased demand (V)

Slow down metabolic processes but, leads to slower growth and reproduction

Bulk flow

Movement of fluid that carries dissolved materials with it, driven by pressure differences

Multicellular organism

• Cells physically and functionally integrated

• Cell-cell connections help cells adhere and communicate

• Cells differentiate into specialized cell types

• Specialized cells organize into tissues

Unicellular colony

• Multiple cells live together but remain independent

• Communication occurs external to cells w/little coordination

• Cells nearly identical

• No true tissues

Aggregation

Previously independent cells come together and become functionally integrated

*Less common

Clonal development

Serial division without separation of cells

*More common

Body plane

General structure of an organism

Life history

Lifetime pattern of growth, reproduction, and survival for an average indv

Cytoskeleton

Network of protein fibers that gives a cell its shape and support and helps move the cell and materials within it

Photoautrophic

Obtain energy from sunlight

*Requires chloroplasts and derivitices

Heterotrophic

Obtain energy and nutrients from preformed, external source

What happens if a single cell gets larger

Volume increases faster than surface area

How to overcome the problem of cell size?

Multicellularity: Subdivide volume into smaller volumes

*Using spheres

__ eukaryotes have mitochondria

ALL

Unicellular eukaryotes ex

Some protists, algae, fungi

Multicellular eukaryotes ex

Plants & animals

Some protists, algae, fungi

Protists

Diverse group of eukaryotes that are not animals, fungi, or land plants

*MOST unicellular

Animal cell characteristics

• NO cell wall

• Contain mitochondria

Plant cells characteristics

• Independently derived cell wall containing cellulose

• Contain mitochondria

• Cells contain chloroplasts

Fungi cells characteristics

• Have independently derived cell walls containing chitin

• Contain mitochondria

Mitosis

Cell division in eukaryotes that results in 2 genetically identical daughter cells

Cell-cell co-operation: Animals

Tight junctions, adherens junctions and desmosomes, gap junctions

Tight junctions in animal cells

Seal between cells, restrict movement of water between cells

Adherens junctions & desmosomes in animal cells

Anchor cells connect via cytoskeleton

Gap junctions in animal cells

Channels between cells, allow cell-cell communication and movement of small molecules

Cell-cell co-operation: Animals

Apoplast, symplast

Apoplast in plant cells

Space between cell wall and middle lamella between adjacent cells

Symplast in plant cells

Cytoplasm inside cells connected through plasmodesmata

Cell-cell co-operation: Fungi

Some cells separated by septa

Septa in fungi

Divide fungal hyphae (filaments) into individual, compartmentalized cells

Tissues in animals

Epithelial, contractile, nervous, connective

Epithelial tissues in animals

Body surfaces; protection/exchange with environment