Biodiversity

The wide, weird, world of life on Earth!

Mr. JewettACS Biology 10

March 2010

Unity & Diversity

• Reproduction

• Homeostasis & feedback

• Movement

• Obtaining & using energy & nutrients

• Structure function

DNA Double Helix: Wikipedia Commons

3 Domains of Life• 1.8 million named species• Likely 10-100 million species total

• Domain Domain Archaea – Archaea – weirdweird bacteria bacteria• Domain Domain Bacteria – “regular” bacteriaBacteria – “regular” bacteria• Domain Domain Eukarya – everything else!Eukarya – everything else!

1.4 BILLION YEARS BY THEMSELVES!

Tree of Life – one view

• Life begins ~3.6 BYAReading the tree:

•Where is the common ancestor of all life?

•How old is it?

•When did invertebrates and vertebrates last share a common ancestor?

•Which of the following are most closely related to humans?

•A. Opuntia

•B. Hagfish

•C. Yeast

Phylogeny and the Tree of Life

• CR Figure 1.14

Cladogram•CR Figure 1.22 Finches – adaptive radiation

Terms to know…

• Why Classify? How should we classify?• Phylogeny – “evolutionary history for a group of

species” (CR p536)• Taxonomy – how organisms are named and classified • Binomial nomenclature – Genus species• Hierarchical classification – DKPCOFGS• Clade, taxon• Cladistics – uses common ancestry to classify• Derived characteristics• Classification slideshow (Stephen Taylor)

Animals

• Heterotrophs• Eukaryotes• Multicellular• (usually) ingest food, break down (digest)

inside bodies• No cell walls – instead use structural

proteins like collagen• Muscle (movement) & nerve cells unique

to animals

History of animal life

• 99% extinct!~550 million years old (maybe more?)

* sponges, cnidarians• Cambrian Explosion (570-535 MYA)

– ½ of all extant animal phyla http://evolution.berkeley.edu/evolibrary/article/_0_0/cambrian_06

– WHY? • Rise in O2, predator-prey relations, developmental flexibility

(new Hox genes)

• Vertebrates common 400 MYA (fish)• land vertebrates 360 MYA (amphibians)

Symmetry

• Fig 32.7 (pg 659)http://www.biologycorner.com/bio1/notes-chap26_animalkingdom.html

Essential Functions of Animals

• Reproduction

• Gas Exchange with Environment (O2/CO2)

• Feeding

• Excretion

• Response: Coordination & Control

• Movement (most animals)

Reproduction

• Usually sexual increases genetic diversity – (respond to environmental

changes)

• Many invertebrates can also reproduce asexually (faster)

Grisha Strundzhev © 2006 Goeasteurope.com

Exchange with Environment

• Circulatory and gas exchange (respiratory) systems

• How do you get food and O2 in, waste and CO2 out?

Coordination & Control• “If I only had a brain…”• Multicellular, need to have someone in charge! • Nerve cells communicate, hormones are

chemical messengers• Only cells with right receptors respond to

hormone signaling

http://ghr.nlm.nih.gov/handbook/illustrations/gh.jpg

Feedback Loops & Homeostasis

• Homeostasis = “steady state”, internal balance

• Negative feedback loop – increase decrease, decrease increase– Ex. Thermoregulation

• Positive feedback loop = increase BIGGER increase – Ex. Hormone signalling, blood clotting

Thermoregulation

• endotherm (warm-blooded)

• ectotherm (cold-blooded)

• Torpor & hibernation

• Important for rates of reactions

Feeding

• Fig 41.6, p881

• Filter / Suspension feeders (baleen whales, sponges)

• Substrate feeders (some caterpillars)

• Fluid feeders (mosquitoes)

• Bulk feeders (snakes, humans)