Zoology Quiz 1 (Bio 2040)

Biodiversity

variation, which within animals, is hard to grasp and understand. this is made sense by the scientific method

who theorized evolution by natural selection

Wallace and Darwin

E.O Wilson

The first naturalist to use biodiversity

Wallace

• went to the Amazon River to study biodiversity

• had a large collection of unknown bugs and other species, but lost most of them

The wallace line

named to show the drastic change in diversity overseas after Wallace travelled to Indonesia, this was the first of many contributions to biogeography

Darwin

Travelled the world, starting in South America (Galápagos Islands). Despite being sick, he worked on two ideas taken from economics and geology

• How can we explain the species difference between the mainland and the Galapagos Island

• How can we explain the differences among islands

Lyell

The man behind geological gradualism. The formation of mountains follows a gradual/uniform process of change over a long period of time.

malthus

The man behind ideas on economics and human population growth. investigated the idea of why human growth couldn’t be sustained over time.

Darwins proposal of evolution

It was not easy. Society was not ready for this, and the church did not accept this idea at all. The scientific community had the questions:

• The theory didn’t explain the origin of changes

• The theory didn’t explain how changes were passed along generations.

Darwin couldn’t explain these, and the answers wouldn’t come until years later

Mendell

researched chromosome heredity. His findings were only recognized 35 years later

Darwin’s theory of perpetual change

Living organisms are not constant or immutable; they change. Examples through fossil records, the effect of pesticides on insects and disease tolerance. This was widely accepted.

Challange of fossil records

Many are incomplete or biased

Darwins theroy of Common Decent

There is a common ancestor for all living forms. saw life as a branching tree. Introduction of homology and analogy.

Homologies

characters derived from a common ancestor. The differences arise from divergent evolution. ex. limb bones in vertebrates (same bone different use)

Analogies

Not from a common ancestor; independent origin. Similarities arise from convergent evolution. (different bone same use)

Cladograms

a nested hierarchy of groups in a branching diagram. tells when groups are related and how closely.

Gradualism

• change occurs as a continuous cumulative process over a long time.

Issues with the idea of gradualism

• mutations

• gaps in fossil records

  • Some say speciation is “sudden” and occasional

Natural Selection

Survival is differential and favours the fittest; the constant struggle for resources makes only the fittest reproduce and live. (survival of the fittest). Extreme cases can cause “mass extinction”

Pre-Cretaceous

When dinosaurs dominated the earth

Post-Cretaceous

Dinosaurs are gone, and mammals undergo adaptive radiation

Darwins theorys of speciation

• Perpetual Change

• Common Decent

• Multiplication of species

• Gradualism

• Natural Selection

Multiplication of species

When habitats change and allow one species to split into various species, having various derived forms brings the question of diversity in an area. Species are not easy to define.

Adaptive Radiation

The formation of various species from a common ancestral form

Typological Speciation

based on morphological similarity. Individuals who look the same are grouped together; this is the most classic concept.

Limitations of typological speciation

species change as they evolve

Biological Speciation

based on similarity, niche and the ability to interbreed and produce viable offspring. This is the most popular concept and relies on species to attract the best mate.

Limitations to biological speciation

hybrid creatures and species with asexual reproduction

Evolutionary Speciation

based on similarities, niche, ability to interbreed and evidence of ancestry.

Limitations of evolutionary speciation

species without ancestry information

Phylogenetic Speciation

based on similarities, niche, ability to interbreed, ancestry information and recognizable genetic variation from isolation.

Limitations of phylogenetic speciation

“recognizable variation” is hard to judge

Allopatric speciation

by spatial and temporal isolation (seperate/distant areas)

Sympatric Process

by niche specialization (coexistence/in the same area)

Formal recognition of a new species

1) an official name

2) an official description

3) an official type

Animal Characteristics

A set of characteristics that define what we call animals.

4 characteristics that make an animal

1) Eukaryote

2) Have no cell wall

3) Heterotrophic

4) Multicellular

Exemption to being heterotrophs as animals

Some animals live in symbiosis with algae, therefore are not only heterotrophs.

Other animals live associated to chemosynthetic bacteria and therefore don’t need to eat

Exemptions to being multicellular animals

A zygote is a single cell, therefore all animals are single celled at some point in there life

Steps of animal architecture

• how complex

• Which symmetry

• Need for a secondary cavity

• What type of development

Why are unicellular organisms small

There metabolism is based on osmosis and therefore requires a high surface area to volume ratio

Complexity increases…

Cell specialization and intercellular dependency

Complexity decreases….

Average cell size

Tissue

A group of cells carrying on a similar function

Epithelial tissue

The coverage or lining of internal and external surfaces, including skin and organs

Connective Tissue

A tissue that binds, protects and supports and gives structure to other tissues and organs

Muscular

Tissue allowing movement by contraction of cells + fibres. At least 3 types

Types of muscle tissue

• smooth

• Cardiac

• Skeletal

Neural Tissue

Tissue controlling and coordinating other tissues. Reception and conduction of stimuli done by neurons and glias

Porifera

Aquatic filter feeders with a basic morphology. They are diploblastic. Instead of a mesoderm they have a mesoglea or mesophyl

Body shapes of porifera

• ascon

• Sycon

• Leucon

Diversity of Porifera

Includes about 8,500 species, most marine habitats. Play important roles for water quality and habitat

Choanocytes

Collar cells, the main and most unique cells in sponges. It can be distinguished by a flagellum and a collar

Collar in Choanocytes

Retains food particles

Flagellum in choanocytes

moves the water

Amoebocytes

multipurpose accociated cells for digestion

Spicule

form the skeleton

Sclerocyte

Cell that secretes spicules

Porocyte

Waterflow regulation

Archaeocyte

digestion

pinacocyte

T-shaped epithelial cell

Fragmentation Asexual Reproduction

A portion of the sponge detaches and builds a new one

Gemmula’s Asexual Reproduction

“seeds” filled with amoebocytes that are sealed during harsh conditions and released once conditions improve

Sponge Sperm

derived from choanocytes

Sponge Oocytes

derived from archaeocytes

External Sexual Reproduction (Sponges)

Sperm and Oocytes are released into the column

Internal Sexual Reproduction (Sponges)

Sperm released in water are caught by another sponge and moved into the mesoglea, where oocytes are waiting

Parenchyma

the product of the fertilization

Dispersal Stage

Important for genetic exchange in sessile species, after drifting the larva will settle and form a new sponge

Classification of Porifera

Based on shape and minerals forming the spicules

Calcarea

3-ray, calcarean (CaCO3) spicules. Mainly in shallow water

Hexactinellida

Glassy sponge with 6-ray siliceous spicules. All deep-sea

Demospongiae

Various shapes, siliceous and collagen. 80% of all sponges. all Leucon

Spherical Symmetry

in many protozoans (not in animals). Infinite plains to divide by

Radial Symmetry

Mainly Cnidarians and Ctenophores. Round or Tubular that can be divided across 2+ plains

Bilateral Symmetry

most animals, divided across one plain

Cnidarians

Diploblastic organisms have mesoglea instead of mesoderm

Gastrovascular Cavity

where extra-cellular digestion takes place

Endoderm

a layer of cell lining the gastrovascualr cavity

Mesoglea

A matrix with cells and fibres that is prominent in the medusa. Works as a hydrostatic skeleton that provides shape and helps float or drift. In a polyp, it is thin and not important.

Ectoderm

Epidermis with a net of sensory cells (ocelli, statocytes) around the top

Cnidocyte

Unique cells with harpoon-like structures (nematocytes) are used for hunting